an assessment of the risk associated ... - secure egg supply

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United States Department of Agriculture Animal and Plant Health Inspection Service Veterinary Services Centers for Epidemiology and Animal Health Center for Animal Disease Information and Analysis 2150 Centre Avenue Building B, Mail Stop 2W4 Fort Collins, CO 80526

Safeguarding Animal Health

An Assessment of the Risk Associated with the Movement of Nest Run Eggs Into, Within, and Outside of a Control Area

During a Highly Pathogenic Avian Influenza Outbreak

June 24, 2010

Collaboration between the Egg Sector Working Group, the University of Minnesota’s Center for Animal Health

and Food Safety, and USDA:APHIS:VS:CEAH.

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Table of Contents TABLE OF CONTENTS ................................................................................................................................... 1 1. ABBREVIATIONS AND DEFINITIONS............................................................................................. 5 2. EXECUTIVE SUMMARY ...................................................................................................................... 8 3. INTRODUCTION ................................................................................................................................... 10 4. SCOPE ...................................................................................................................................................... 12

4.1 FACILITIES COVERED UNDER THIS RISK ASSESSMENT .............................................................................12 4.2 TYPES OF MOVEMENTS ADDRESSED UNDER THIS RISK ASSESSMENT .....................................................12 4.3 PREVENTIVE MEASURES CONSIDERED IN THIS RISK ASSESSMENT ..........................................................12 4.4 SCOPE JUSTIFICATION .................................................................................................................................13

5. SIGNIFICANT ASSUMPTIONS USED IN THE RISK ASSESSMENT...................................... 14 6. BACKGROUND INFORMATION ON NEST RUN EGG OPERATIONS.................................. 15

6.1 DEFINITION OF NEST RUN EGGS AND NEST RUN EGG FARMS..................................................................15 6.2 OVERVIEW OF NEST RUN EGG OPERATIONS IN THE UNITED STATES.......................................................15

6.2.1 Industry Structure..............................................................................................................................15 6.2.2 Nest Run Egg Distribution and Logistics.........................................................................................16

6.2.2.1 Nest Run Egg Supply Chain Members ..................................................................................................... 16 6.2.2.2 Egg Packing Materials .............................................................................................................................. 17 6.2.2.3 Movement of Eggs and Egg Packing Materials....................................................................................... 17

6.3 MAJOR STEPS IN THE PROCESSING OF NEST RUN EGGS ............................................................................18 6.4 ANALYSIS OF RISK OF HPAI VIRUS SPREAD THROUGH MOVEMENT OF NEST RUN EGGS......................19

7. THE RISK THAT HPAI VIRUS CONTAMINATED NEST RUN EGGS ARE MOVED FROM AN INFECTED BUT UNDETECTED PREMISES........................................................................................... 21

7.1 BACKGROUND INFORMATION .....................................................................................................................21 7.2 SUMMARY OF KEY DISEASE TRANSMISSION MODEL PARAMETER ESTIMATES AND RESULTS ...............22 7.3 CONCLUSION................................................................................................................................................24

8. LIKELIHOOD OF EGG PACKING MATERIALS MOVED FROM AN INFECTED BUT UNDETECTED BELT GATHERED PREMISES BEING CONTAMINATED WITH HPAI VIRUS26

8.1 OVERVIEW ...................................................................................................................................................26 8.2 EVALUATION OF RISK .................................................................................................................................27

8.2.1 The Likelihood and Degree of Contamination of Egg Packing Materials from an Infected but Undetected Farm by Contact with Contaminated Egg Surfaces....................................................................27 8.2.2 The Likelihood and Degree of Contamination of Egg Packing Materials from an Infected but Undetected Farm due to Leakage of Contaminated Egg Contents ................................................................28 8.2.3 The Likelihood and Degree of Contamination of Egg Packing Materials via Personnel or Environment.......................................................................................................................................................29

8.2.3.1 Cross-contamination via Personnel ......................................................................................................... 29 8.2.3.2 Cross-contamination via Environment..................................................................................................... 29

8.3 CONCLUSION................................................................................................................................................32 9. LIKELIHOOD OF HPAI VIRUS ON EGG PACKING MATERIALS AFTER CLEANING AND DISINFECTION................................................................................................................................................ 34

9.1 OVERVIEW ...................................................................................................................................................34 9.2 PREVENTIVE MEASURES .............................................................................................................................35

9.2.1 Current Preventive Measures ............................................................................................................35 9.2.2 Preventive Measures in the Event of an HPAI Outbreak.................................................................35

9.2.2.1 Procedures for Mechanical Washing and Disinfection of Nonporous Materials .................................. 35 9.2.2.2 Procedures for Manual Cleaning and Disinfection of Wood Based (Porous) Egg Packing Materials35

9.3 EVALUATION OF RISK .................................................................................................................................36

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9.3.1 The Risk of HPAI Virus Being Present on Egg Packing Materials after Washing ........................36 9.3.2 The Risk of HPAI Being Present on Egg Packing Materials after Disinfection ............................37

9.3.2.1 Degree of HPAI Virus Inactivation on Plastic Egg Packing Materials with Sanitization/Disinfection. 37 9.3.2.2 Degree of HPAI Virus Inactivation on Wood Egg Packing Materials with Sanitization/Disinfection . 38

9.3.3 Overall Impact of Washing and Disinfection of Egg Packing Materials .......................................38 9.3.3.1 Nonporous Egg Packing Materials ...................................................................................................... 38 9.3.3.2 Porous Egg Packing Materials................................................................................................................ 39

9.4 CONCLUSION................................................................................................................................................40 10. RISK OF EGG PACKING MATERIALS LEAVING THE PROCESSING CENTER RESULTING IN HPAI SPREAD TO OTHER POULTRY PREMISES.......................................................................... 41

10.1 INTRODUCTION ........................................................................................................................................41 10.2 EVALUATION OF RISK .............................................................................................................................42

10.2.1 Likelihood that Egg Packing Materials Contaminated Prior to Cleaning and Disinfection are Returned to the Nest Run Farm Before HPAI Infection is Detected ..............................................................42 10.2.2 Risk that Contaminated Egg Packing Materials Leaving the Off-line Processing Center Result in HPAI Spread to Susceptible Poultry ................................................................................................................44

10.2.2.1 Risk for Plastic Egg Packing Materials ........................................................................................................ 44 10.2.2.2 Risk for Porous Egg Packing Materials ....................................................................................................... 44

10.3 NOTE ON MATERIAL IDENTIFICATION FOR RETURN OF EGG PACKING MATERIALS TO THE PREMISES OF ORIGIN .....................................................................................................................................................................45 10.4 CONCLUSION............................................................................................................................................46

11. RISK OF HPAI SPREAD TO OTHER POULTRY PREMISES VIA VEHICLE OR DRIVER LEAVING THE PROCESSING CENTER................................................................................................... 48

11.1 BACKGROUND INFORMATION .................................................................................................................48 11.2 PREVENTIVE MEASURES .........................................................................................................................49

11.2.1 Current Preventive Measures.......................................................................................................49 11.2.2 Preventive Measures during an Outbreak...................................................................................49

11.3 EVALUATION OF RISK .............................................................................................................................50 11.3.1 Risk that Susceptible Poultry are Exposed to HPAI Virus via Vehicle Transporting Egg Packing Materials from the Processing Center .............................................................................................................50

11.3.1.1 Risk that Susceptible Poultry are Exposed to HPAI Virus via Interior of the Vehicle Transporting Egg Packing Materials from the Processing Center ............................................................................................................ 50 11.3.1.2 Risk of Cleaning and Disinfection not Inactivating HPAI Virus on the Vehicle Exterior ........................... 52

11.3.2 Risk of the Driver of the Vehicle Transporting Cleaned and Disinfected Packing Materials being Contaminated with HPAI Virus ........................................................................................................................52

11.4 CONCLUSION............................................................................................................................................53 12. RISK EVALUATION FOR NEST RUN PREMISES THAT HAND GATHER EGGS............. 54

12.1 BACKGROUND INFORMATION .................................................................................................................54 12.2 EVALUATION OF RISK .............................................................................................................................55

12.2.1 Risk that Movement of Nest Run Eggs from an Infected but Undetected Premises that Hand Gathers Eggs Results in HPAI Spread to Susceptible Poultry .......................................................................55 12.2.2 Risk that Movement of Cleaned and Disinfected Egg Packing Materials to a Hand Gathering Premises Results in HPAI Spread to Susceptible Poultry...............................................................................56

12.3 CONCLUSION............................................................................................................................................56 13. OVERALL CONCLUSIONS ................................................................................................................ 58 REFERENCES .................................................................................................................................................. 60 ACKNOWLEDGEMENTS ............................................................................................................................. 65 APPENDIX 1. SELECTED SECTIONS OF EGG MOVEMENT CONTROL RESPONSE PLAN FROM THE DRAFT USDA-APHIS-VS SECURE EGG SUPPLY PLAN ........................................................... 66

4.1 RESPONSE ZONES AND PREMISE DESIGNATIONS FOR THE EMC RESPONSE PLAN...................................68

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4.1.1 Flocks That Are Determined to Be Infected Premises By Epidemiological Investigation and/or Diagnostic Testing.............................................................................................................................................68 4.1.2 Flocks That Are Determined to Be Contact Premises By Epidemiological Investigation.............69 4.1.3 Flocks That Are Determined to Be Suspect Premises By Epidemiological Investigation..................70 4.1.4 Flocks That Are Designated as At-Risk Premises Prior to Epidemiological Investigation ..........72 4.1.5 Flocks That Are Determined to Be Monitored Premises By Epidemiological Investigation ........72 4.1.6 Flocks That Are Determined to Be Free Premises By Epidemiological Investigation ..................74

FIGURE 4.8 PREMISES DESIGNATIONS ................................................................................................................75 4.2 DETERMINATION OF NON-INFECTED LAYER INDUSTRY FLOCKS IN THE CONTROL AREA .....................75 4.3 MOVEMENT OF EGG INDUSTRY PRODUCTS................................................................................................76

4.3.1 USDA FSIS Inspected Pasteurized Egg Products, or Precooked Egg Products ..............................76 4.3.2 Non-pasteurized Liquid Egg Products ..................................................................................................76 4.3.3 Washed and sanitized Shell Eggs.....................................................................................................77 4.3.4 Nest Run Shell Eggs ..........................................................................................................................78 4.3.5 Hatching Eggs....................................................................................................................................78 4.3.6 Day-Old Chicks ..................................................................................................................................79 4.3.7 Broken Egg Shells .............................................................................................................................80 4.3.8 Inedible Egg .......................................................................................................................................80

4.4 DETERMINATION OF RELEASE OF MOVEMENT RESTRICTIONS..................................................................81 4.5 REFERENCES ................................................................................................................................................81

APPENDIX 2. SELECTED SECTIONS OF MODEL CLEANING AND DISINFECTION GUIDELINES FROM THE DRAFT USDA-APHIS-VS SECURE EGG SUPPLY PLAN .................. 83 APPENDIX 3. EXAMPLE INDUSTRY DESCRIPTION OF ORGANIZATION AND TRACKING OF NEST RUN SHIPMENTS................................................................................................................................ 90 APPENDIX 4. REGISTERED ANTIMICROBIAL PRODUCTS WITH LABEL CLAIMS FOR AVIAN (BIRD) FLU DISINFECTANTS..................................................................................................................... 92 APPENDIX 5. EFFICACY DATA REQUIREMENTS FOR VIRUCIDES........................................... 96 APPENDIX 6. VIRUCIDE TEST RESULTS.............................................................................................. 98 APPENDIX 7. EXPERT OPINION ON THE INACTIVATION OF AVIAN INFLUENZA ........... 100 APPENDIX 8. QUANTITATIVE RESULTS ON CONTAMINATION OF EGG PACKING MATERIALS AT NEST RUN FARMS ...................................................................................................... 109 APPENDIX 9. QUANTITATIVE RESULTS ON THE IMPACT OF CLEANING AND DISINFECTION ON POROUS PACKING MATERIALS ..................................................................... 111 APPENDIX 10. 9CFR590 SECTION CONTENTS AND ELECTRONIC CFR WEB ADDRESS.. 115 APPENDIX 11. DIAGRAM OF EGG PROCESSING PLANT ............................................................. 120 APPENDIX 12. ESTIMATION OF VIRAL TITERS ON SURFACES CONTAMINATED FROM FLOORS OF NEST RUN PREMISES ........................................................................................................ 120 APPENDIX 13. THE USE OF “NEGLIGIBLE RISK” IN THIS ASSESSMENT ............................. 126 APPENDIX 14. THE USE OF “LOW RISK” IN THIS ASSESSMENT............................................... 128

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1. Abbreviations and Definitions AHPA U.S. Animal Health Protection Act

APHIS Animal and Plant Health Inspection Service (USDA) AI Avian influenza

CEAH Centers for Epidemiology and Animal Health (USDA: APHIS: VS) CFR U.S. Code of Federal Regulations

EPA U.S. Environmental Protection Agency GMP Good Manufacturing Practice

FSIS Food Safety Inspection Service (USDA) HA Hemagglutinin

HACCP Hazard Analysis and Critical Control Point HPAI Highly pathogenic avian influenza

HPNAI Highly pathogenic notifiable avian influenza LPAI Low pathogenic avian influenza

NA Neuraminidase NAHEMS National Animal Health Emergency Management System (USDA) OIE World Organization for Animal Health (formerly Office International des

Epizooties) PLE Pasteurized liquid egg

P.I. Probability Interval PPE Personnel protective equipment

RRT-PCR Real-time Reverse Transcription Polymerase Chain Reaction U.S. United States of America

USDA United States Department of Agriculture VS Veterinary Services (USDA: APHIS) Buffer zone

The zone immediately surrounding the infected zone. The buffer zone and the infected zone comprise the control area.

Check Check means an egg that has a broken shell or crack in the shell but has its shell membranes intact and contents not leaking.

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Contract farms Farms that produce nest run eggs for another company through contractual agreements.

Control area

A control area, consisting of an infected zone and a buffer surveillance zone, will be established to ensure the rapid and effective containment of the disease. Initially, the entire State, Commonwealth, Tribal Nation or territory may be declared a control area and subject to movement restrictions until appropriate surveillance and epidemiological evidence has been evaluated and the extent of the outbreak is known. All susceptible bird and other livestock movement will be stopped for a period long enough to determine the scope of the disease outbreak. The potential modes of transmission of HPAI will be considered when determining the minimum size and shape of a control area. Movement control through the use of permits should be maintained until the disease is eradicated.

Dirty egg Dirty egg or Dirties means an egg(s) that has an unbroken shell with adhering dirt or foreign material.

Egg

The shell egg of the domesticated chicken. Shell eggs of turkeys, ducks, geese, and guineas are outside the scope of this assessment.

Egg Movement Control (EMC) Response plan

The EMC Response plan identifies specific surveillance, biosecurity, cleaning and disinfecting practices for moving different types of eggs, egg products and day-old chicks within, out of and into a HPAI Control Area. The EMC Response plan is part of the USDA-APHIS_VS Draft Secure Egg Supply plan.

Egg packing materials

Packing materials used in the transport of nest run eggs such as plastic flats, pallets, nest run carts, divider boards etc.

Infected zone

In an outbreak of HPAI, an infected zone will encompass the perimeter of all presumptive or confirmed positive premises (“infected premises”) and include as many “contact premises” as the situation requires logistically or epidemiologically. Activities in an infected zone include:

• Preventing products from birds and other susceptible animals from leaving the zone unless a risk assessment determines that such movement can be permitted.

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• Preventing movement of vehicles, equipment, and nonsusceptible animals out of the zone unless appropriate biosecurity procedures (as determined by a risk assessment) are followed.

• Active surveillance for HPAI, including monitoring of flocks for clinical signs such as changes in feed and water intake, a drop in egg production, an increase in daily mortality above an established threshold, and submission of swabs from the daily mortality for real-time reverse transcription polymerase chain reaction (RRT-PCR) testing each day.

In-line processing centers

Egg processing facilities that source eggs from poultry flocks that are present on the premises.

Movement permit

A VS Form 1-27, a State-issued permit, or a letter—customized to the applicant’s situation—generated by the Permit Team and issued at the discretion of Incident Command to allow the movement of nest run eggs from a premises or a geographic area described in a quarantine order.

Nest run egg

Eggs that have been packed as they come from the production facilities without having been washed, sized, and/or candled for quality, with the exception that some checks, dirties or obvious under-grades may have been removed.

Nest run farms (Off-line)

Farms producing nest run eggs as their final product and transporting them to further processing off-site.

Off-line processing centers Egg processing facilities that do not have poultry on the premises and source eggs from nest run farms.

Restricted egg Restricted egg means any check, dirty egg, incubator reject, inedible, leaker, or loss.

Shell egg For this assessment, we define shell eggs as washed eggs.

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2. Executive Summary This document assesses the risk that the movement of nest run eggs and associated materials during a highly pathogenic avian influenza (HPAI) outbreak in the poultry egg industry in the United States will result in HPAI infection on other poultry premises. This assessment evaluates risks of HPAI spread associated with: 1) movement of nest run eggs to processing centers that do not have poultry on the premises, and 2) movement of cleaned and disinfected egg packing materials to the premises that shipped the eggs. This assessment is applicable to egg layer farms and processing centers that follow the Egg Movement Control (EMC) Response Plan described in the USDA APHIS Veterinary Services Secure Egg Supply plan (USDA-APHIS-VS Secure Egg Supply plan) and implement the specified active surveillance protocol and Model Cleaning and Disinfection Guidelines. The active surveillance protocol requires monitoring of flocks for clinical signs such as changes in feed and water intake, a drop in egg production, an increase in daily mortality above an established threshold, and submission of swabs from the daily mortality for real-time reverse transcription polymerase chain reaction (RRT-PCR) testing each day. This risk assessment is a joint effort between the Egg Products Industry working group, the University of Minnesota’s Center for Animal Health and Food Safety, and the United States Department of Agriculture (USDA)a to support permits for moving nest run eggs and associated materials safely and in a timely fashion during an outbreak. This risk assessment is intended to identify pathways of HPAI transmission associated with the movement of nest run eggs, and assess their corresponding likelihoods of carrying the virus off of an infected premises and causing infection on another poultry premises despite implementation of all standard preventive measures as well as outbreak-specific measures. This risk assessment will ultimately provide the framework necessary for decision makers to:

a) Quickly assess the effectiveness of preventive measures as they pertain specifically to the movement of nest run eggs and associated egg packing materials.

b) Implement a permit system to allow uninfected premises to move nest run eggs into, within, and outside of the control area during an HPAI outbreak.

To address these objectives, we first estimated the number of contaminated eggs that might be moved from an infected but undetected flock based on simulation models of HPAI transmission and active surveillance. Next, we evaluated the likelihood and degree of HPAI virus contamination of egg packing materials from an infected but undetected premises. We then estimated the degree of HPAI virus inactivation on various types of egg packing materials with cleaning and disinfection. Finally, we evaluated the risks associated with post-cleaning and disinfection handling and transportation of egg packing materials. In particular, this document assesses:

a) Likelihood of nest run eggs moved from an infected but undetected premises being contaminated with HPAI virus.

a Specifically, the Animal and Plant Health Inspection Service (APHIS) Veterinary Services (VS) Centers for Epidemiology and Animal Health (CEAH) within the USDA.

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b) Likelihood of egg packing materials moved from an infected but undetected premises being contaminated with HPAI virus.

c) Likelihood of HPAI virus remaining on egg packing materials after cleaning and disinfection at the processing center.

d) Risk of egg packing materials leaving the processing center resulting in HPAI spread to other poultry premises.

e) Risk of HPAI spread to other poultry premises via vehicle or driver leaving the processing center.

This document is an evolving product-specific risk assessment that will be reviewed and updated as necessary before and during an outbreak to incorporate the latest scientific information and preventive measures. If the Incident Command System is activated in response to an HPAI outbreak, APHIS (and Incident Command staff) will review this risk assessment with respect to the situation in order to assess industry requests for movement of nest run eggs.

Overall Finding and Conclusion

The risk that movement of nest run eggs into, within, and outside of a control area during an HPAI outbreak results in the infection of another poultry production

premises is low provided that applicable preventive measures from the Egg Movement Control Response plan and the Model Cleaning and Disinfection Guidelines included

in the USDA-APHIS-VS Secure Egg Supply Plan are strictly followed.

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3. Introduction In the event of a highly pathogenic avian influenza (HPAI) outbreak in the U.S. poultry industry, local, State and Federal authorities will implement a foreign animal disease emergency response. This response consists of a control and eradication strategy that will utilize depopulation, quarantine and movement control measures to prevent further spread of HPAI virus. In addition to compliance with such measures, State and/or Federal authorities will also issue official permits to allow movement of birds and their products from premises identified in a quarantine order during an outbreak. A request for a movement permit must be supported by a risk assessment (or some scientifically-based logical argument) to demonstrate that the risk of HPAI spread associated with the movement of the product in question is acceptable.b Completing these types of risk assessments in a timely manner during an outbreak can be challenging. Risk assessments can take more time to conduct than the shelf-life of some of the perishable ingredients or products that need to be moved. In addition, the available storage capacity might be inadequate for holding the product while the risk assessment is being completed and may result in disposal of product. For these products, the risk may be evaluated before an outbreak occurs. Nest run eggs are one such product. The purpose of this document is to determine the risk of disease spread due to the movement of nest run eggs produced from an undetected, notifiable, HPAI-positive flock in a control area. If HPAI infection has been detected, it is assumed that movement of eggs would not be allowed, and any associated laying facilities would be depopulated. Hence, nest run eggs from a known (i.e., detected) positive flock are not considered in this assessment. This document assesses the risk associated with the movement of nest run eggs into, within, and outside of a control area during an HPAI outbreak. The movement of washed and sanitized shell eggs and liquid egg products that are produced by the processing of nest run eggs have been addressed in previous risk assessments. The facilities covered in this document are only layer farms that move nest run eggs to off-line processing centers that do not have poultry on the premises. It is assumed that the layer farms and processing centers are participants in the Egg Movement Control (EMC) Response Plan described in the USDA APHIS Veterinary Services Secure Egg Supply plan (USDA-APHIS-VS Secure Egg Supply plan) (Appendix 1), follow the specified Model Cleaning and Disinfection Guidelines within this plan (pertinent guidelines for this risk assessment are included as Appendix 2), and participate in the active surveillance protocol to be implemented by industry in conjunction with APHIS during an outbreak. The risk evaluations take into consideration all applicable regulations including preventive measures already in place as well as additional preventive measures that will be implemented during an outbreak.c b During an outbreak, APHIS conducts numerous product-specific risk assessments, taking into consideration all permit requirements and preventive measures currently in place. c Normal day-to-day operations and preventive measures are in place via Good Manufacturing Practices (GMP), State regulations and Federal regulations as required by FSIS, FDA, and APHIS.

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This risk assessment does not guarantee that movement will be permitted during an HPAI outbreak. However, this document provides the framework necessary for decision makers to quickly assess the effectiveness of the preventive measures as they pertain specifically to transport of nest run eggs and associated egg packing materials. This risk assessment will also allow decision makers to consider implementation of additional control measures which would allow nest run egg movement for further processing into, within and outside of the control area during an HPAI outbreak.

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4. Scope

This section describes the scope of the assessment with respect to the types of movements addressed, the facilities covered, and the key preventive measures considered.

4.1 Facilities Covered Under this Risk Assessment

This risk assessment is applicable to egg layer premises that produce and move nest run eggs to further processing and abide by the following protocols in the event of an HPAI outbreak:

• The Egg Movement Control (EMC) Response plan described in the USDA-APHIS -VS Secure Egg Supply plan (Appendix 1).

• The Model Cleaning and Disinfection Guidelines included in the USDA-APHIS -VS Secure Egg Supply plan (Appendix 2).d

4.2 Types of Movements Addressed Under this Risk Assessment

This risk assessment addresses the following types of movements into, within and outside of the control area during an HPAI outbreak:

• Movement of nest run eggs to an off-line processing center that does not have poultry on the premises.

• Movement of new or cleaned and disinfected egg packing materials from an off-line processing center to the premises of origin of the materials.

4.3 Preventive Measures Considered in this Risk Assessment

Key preventive measures from the EMC Response plan and Model Cleaning and Disinfection Guidelines (Appendices 1 and 2) that are evaluated in this assessment are as follows:

• Active surveillance protocol: Monitoring of flocks for clinical signs of illness, changes in feed and water intake, drop in egg production, an increase in daily mortality above an established threshold, and submission of a pooled sample of swabs for RRT-PCR testing from 5 randomly chosen birds among the daily mortality each day.

• Use of disposable materials, or cleaning and disinfection of egg packing materials in accordance with the Model Cleaning and Disinfection Guidelines.

• Return of cleaned and disinfected egg packing materials to the premises of origin after at least 24 hours have passed, allowing for confirmation of negative RRT-PCR test results from the two most recently submitted samples for all flocks on the premises.

d The EMC Response plan is included as Appendix 1 of this risk assessment. The EMC Response plan contains specific guidelines for cleaning and disinfection procedures to be implemented during an HPAI outbreak. For ease of access, we included the portions of these guidelines that are relevant to cleaning and disinfections of egg packing materials as Appendix 2 of this risk assessment.

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• Cleaning and disinfection of the vehicle interior and exterior and biosecurity measures for the driver.

• Cleaning and disinfection of the shipping dock, receiving storage areas, and connecting passages at the processing center after receiving eggs from the control area during an HPAI outbreak.

4.4 Scope Justification

The current egg industry biosecurity and sanitary measures for the movement of nest run eggs and materials include Good Manufacturing Practices (GMPs) such as cleaning and disinfection of egg flats, and returning racks or pallets to the premises of origin. As these practices are not regulated, there may be considerable variability in their design and implementation. The EMC Response plan identifies product specific biosecurity protocols and cleaning and disinfection guidelines for the movement of various types of eggs, egg products and egg packing materials during an HPAI outbreak. The plan also specifies an active surveillance protocol to be implemented by industry in conjunction with APHIS during an outbreak. Given that the current egg industry product specific biosecurity and cleaning and disinfection procedures associated with the movement of nest run eggs are not standardized or regulated, we chose to focus on the preventive measures to be implemented during an outbreak for our risk evaluation.

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5. Significant Assumptions Used in the Risk Assessment This assessment is proactive in nature and cannot address the specific circumstances surrounding an outbreak in detail. Therefore, we are making some assumptions to establish context and applicability. These assumptions are:

a) That a HPAI outbreak has been detected, APHIS is implementing the HPAI Response Plan, and some degree of planning has taken place at other levels. The APHIS HPAI Response Plan is intended to complement regional, State, and industry plans and APHIS recommends their continued development.

b) Nest run egg production facilities may have HPAI infection in their laying flocks but it has not yet been detected. If there was absolute certainty that HPAI infection was absent there would be no risk. On the other hand, if HPAI infection has been detected, it is assumed that Incident Command would shut down the production premises, movement of eggs and materials would not be allowed, and any associated laying facilities would be depopulated. This situation also does not pose a risk associated with movement of nest run eggs as the premises would cease production and would then be quarantined, depopulated, cleaned and disinfected before resuming production.

c) The assessment is applicable to most (but not all) of the situations that may arise during an outbreak. As discussed in the movement section, permits to move nest run eggs may be issued for movement to processing at an off-line (without the presence of hens) facility or for movement under conditions described on a movement permit. These conditions depend on the circumstances and cannot be known in advance. Therefore, the risk will depend on the circumstances and this assessment can only provide information and not generate recommendations.

d) That all relevant preventive measures from the EMC Response plan and associated Model Cleaning and Disinfection Guidelines are strictly followed. The assessment does not evaluate the risk that the preventive measures in the EMC Response plan are incorrectly implemented either intentionally or unintentionally.

e) The assessment focuses on the risk that movement of nest run eggs will result in HPAI spread to other susceptible poultry. Although the risks to humans or wildlife associated with the production or movement of nest run eggs are critical concerns that should be addressed, they are outside the scope of this assessment. The draft National Highly Pathogenic Avian Influenza Response Plan has personnel safety measures designed to mitigate the risk to humans.

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6. Background Information on Nest Run Egg Operations

6.1 Definition of Nest Run Eggs and Nest Run Egg Farms 7CFR57.1 defines nest run eggs as follows:

Nest run egg means eggs that have been packed as they come from the production facilities without having been washed, sized and/or candled for quality, with the exception that some checks, dirties, or other obvious under grades may have been removed. For the purpose of this risk assessment, nest run farms are those which produce nest run eggs as their final product and transport them off the farm for further processing.

6.2 Overview of Nest Run Egg Operations in the United States 6.2.1 Industry Structure According to the USDA APHIS Layer 1999 survey covering 15 states and over 75 percent of table egg layers in the U.S., nest run farms account for over 80 percent of farm sites in the U.S.1 Many of these farms produce eggs for another company, and are thus considered “contract farms.” Contractual agreements determine the details of transportation of eggs and egg packing materials to processing centers, as well as return of reusable materials to the nest run farms. Nest run farms vary in size, from “small” or niche market farms to “large,” production oriented farms. Niche market farms Niche market farms include small and large cage free, free range, organic and nutraceutical, and such farms may have as few as several hundred to several thousand hens. Although farms smaller than 20,000 birds account for less than 10 percent of the egg production, they account for a majority of farm sites in the U.S. The USDA National Animal Health Monitoring System study of small enterprise chicken farms in 2007 found the biosecurity and farm management practices in these farms to be highly variable.2 Furthermore, smaller niche market farms (<10,000) are likely to hand gather the eggs, but larger farms depend on mechanical gathering using belts. Large, production oriented farms Large, production oriented nest run egg farms, together with in-line farms, account for the majority of egg production in the U.S. Nest run egg farms currently range from about 75,000 to 500,000 hens and are typically mechanically gathered using belts. Some large farms in the western U.S. were still practicing hand gathering as of 1999.1 The specific biosecurity practices associated with egg handling and transportation for niche market farms may be significantly different from the practices in large production oriented farms. Given these differences, our evaluation focuses on the more standardized practices of large production oriented nest run farms. This risk assessment is thus only applicable to nest run farms that handle and transport eggs and egg packing materials in a manner comparable to large, production oriented nest run farms.

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6.2.2 Nest Run Egg Distribution and Logistics 6.2.2.1 Nest Run Egg Supply Chain Members The supply chain members relevant to nest run egg production and processing are diagrammed in Figure 1. These include nest run farms, distribution centers, off-line processing centers and mixed processing centers (defined below). Figure 1 represents the flow of eggs and materials in a non-outbreak situation. Figure 2 shows how eggs and materials would be moved in an outbreak situation. Nest run farms: Farms producing nest run eggs as their final product and transporting them to further processing off-site.

Hen house

Off-line Processing CenterWashing Grading or

Breaking

Nest Run Farm(Off-line)

Egg packing location

Eggs delivered to off-line processing center (no hens on premises)

Movement of eggs/materialsCirculation of materials

Nest run eggs moved off -farm along with associated materials

HenhouseHen house

Off-line Processing CenterWashing Grading or

Breaking

Nest Run Farm(Off-line)


Eggs delivered to off-line processing center (no hens on premises)


Nest run eggs moved off -farm along with associated materials

Henhouse

Figure 2. Movement of nest run eggs and packaging materials in an outbreak situation.

Henhouse

Distribution Center

Off -line Processing Center

Washing Grading or Breaking

Mixed Operation Processing CenterWashing Grading or

Breaking

Henhouse

Henhouse


A Truck carrying eggs from Farm X stops to pick up eggs at Farm Y

B Eggs delivered to distribution center

Farm XNest Run Farm

(Off -line)

Nest Run Farm (Off -line)

Farm Y

A

B

D SIDE LOADING: Eggs integrated into mixed operation for processing

C

Nest run eggs moved off-farm along with associated materials

D

B

C Eggs delivered to off -line processing center


Farm Z


Henhouse

Distribution Center

Off -line Processing Center

Washing Grading or Breaking

Mixed Operation Processing CenterWashing Grading or

Breaking

Henhouse

Henhouse


A Truck carrying eggs from Farm X stops to pick up eggs at Farm Y

B Eggs delivered to distribution center

Farm XNest Run Farm

(Off -line)

Nest Run Farm (Off -line)

Farm Y

A

B

D SIDE LOADING: Eggs integrated into mixed operation for processing

C

Nest run eggs moved off-farm along with associated materials

D

B

C Eggs delivered to off -line processing center


Farm Z


Figure 1. Overview of movement of nest run eggs and packaging materials in a non-outbreak situation.

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Distribution centers: Facilities that combine eggs from several nest run farms and organize transport to processing facilities. Off-line processing centers: Egg processing facilities that receive all of their eggs from nest run farms and do not have poultry on the premises. Mixed processing centers: Egg processing facilities that receive eggs from layer flocks on-site as well as off-site nest run farms. The eggs from the nest run farms are thus “side loaded” into the mixed processing center.

6.2.2.2 Egg Packing Materials Nest run eggs are placed on paper, cardboard or plastic flats (Figure 3) that are stacked on racks, pallets or carts (Figure 4) for movement to processing facilities. Stacks of flats may be separated with divider boards made of cardboard, plastic or wood; the divider boards are typically placed between groups of 6 flats. Wood or cardboard “tic-tacs” may also be used in egg packing to vertically support stacks of egg flats. The racks or pallets used in the egg industry are made of either plastic or wood.

Niche market farms normally pack eggs on paper or cardboard flats and stack the flats on wood pallets. Divider boards used in these situations are typically made of cardboard. Some exceptions may occur in each of these situations.

6.2.2.3 Movement of Eggs and Egg Packing Materials During normal operations without an HPAI outbreak, nest run eggs may be transported to distribution facilities, off-line processing facilities or mixed processing facilities as shown in Figure 1. In the event of an HPAI outbreak, the EMC Response plan (Appendix 2) requires nest run eggs to be shipped directly and only to an off-line processing facility, thereby negating the practice of side-loading eggs into a mixed processing center (Figure 2).

Figure 4. Nest run eggs stacked in flats and placed on carts in a pre-processing cooler.

Figure 3. Empty egg flats stacked on a cart.

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Nest run eggs are typically stored in refrigerated coolers at the farm until they are transported to processing. FDA regulation 21CFR118.4 requires eggs to be held at or below 45°F beginning 36 hours after time of lay.e The USDA APHIS Layer 1999 survey indicates that eggs are picked up every 1-2 days in 48.5 percent of the farms and every 3-5 days in 45 percent of the farms.1 As mentioned previously, most nest run eggs are marketed through contractual agreements with individual companies.3 Typically, these agreements incorporate the exchange of used egg packing materials from the processing center after delivering a shipment of eggs. Given these arrangements, it is possible for egg packing materials from various farms to be comingled at the processing center and circulated among different nest run farms. Some agreements specify the return of reusable egg packing materials to the farm that shipped them, forming a closed loop system for the movement of egg packing materials between the nest run farm and the processing center. In this case, the plastic flats, divider boards, and pallets may be cleaned and disinfected before being returned to the producer. The vehicles used to transport egg packing materials back to the egg production facility are often the same vehicles used to transport nest run eggs to egg processing plants.

6.3 Major Steps in the Processing of Nest Run Eggs

The major steps in the processing of nest run eggs in non-outbreak situations are as follows: 1. Egg collection and removal of malformed or leaking eggs 2. Transportation 3. Washing of egg packing materials and return to farm 1. Egg collection and removal of cracked or leaking eggs (at nest run farm) Nest run eggs are collected in henhouses either by hand or by automated conveyor belt and moved to the egg packing room. By definition, nest run eggs are unwashed. Prior to introduction to a processing operation, however, workers may remove cracked or leaking eggs (also referred to as “checks”). The remaining eggs are placed in egg flats and stacked onto pallets or carts. If processing does not occur for at least 36 hours, the palletized eggs are refrigerated until they are transported to processing. The refrigeration time typically ranges from 1 to 6 days. 2. Transportation Eggs are transported from farms by truck to either distribution centers or processing centers. About 85 percent of these trucks are refrigerated.3 Truck drivers are generally responsible for off-loading empty egg packing materials at the farm and loading the nest run eggs. At the processing center, the truck driver generally unloads the eggs and loads new or cleaned egg packing materials for delivery back to the farm. 3. Washing of egg packing materials and return to farm (at off-line processing center)

e This requirement will be effective from July 2010 for producers with more than 3000 layers.

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Reusable plastic flats are generally washed and disinfected using mechanical washers with detergent (USDA APHIS Layer 1999 survey).1 Washed egg flats are stacked and stored until they are returned to the farm. Paper or cardboard egg packing materials are discarded. Large materials such as racks, pallets or carts may be sprayed off; however, these items are not routinely washed.

6.4 Analysis of Risk of HPAI Virus Spread through Movement of Nest Run Eggs The EMC Response plan requires nest run eggs to be shipped directly and only to an off-line processing facility in the event of an HPAI outbreak (Figure 2). At the processing center, the nest run eggs are washed and sanitized. After this step, the eggs are either reclassified as shell eggs or broken and reclassified as liquid egg.f The primary pathway for the risk of HPAI spread associated with the movement of nest run eggs is through the movement of reusable egg packing materials from the off-line processing center back to nest run farms. Specifically, the movement of reusable egg packing materials to nest run farms provides an opportunity for the spread of HPAI infection to susceptible poultry through a contaminated vehicle, driver or egg packing materials. Such contamination could be directly from another nest run farm that is infected but undetected, or from cross-contamination of materials occurring at the processing center. We evaluated the risk of virus spread through the movement of nest run eggs in three parts:

1. The risk that egg packing materials, vehicles or personnel entering the processing center are contaminated with HPAI virus.

2. The risk of cross-contamination of egg packing materials, vehicles or personnel occurring at the processing center.

3. The risk that HPAI virus contaminated egg packing materials, vehicles or personnel leave the processing center and transmit HPAI to susceptible poultry.

The pathways by which nest run eggs and egg packing materials may become contaminated with HPAI virus prior to leaving an infected but undetected premises are as follows: Nest run eggs

• Internal contamination when laid by an infected hen • Cross-contamination from the environment or personnel

Egg flats • Contact with contaminated egg surfaces • Leakage of contaminated eggs • Cross-contamination from the environment or personnel

Supporting materials • Leakage of internally contaminated eggs • Cross-contamination from the environment or personnel

f Risks associated with the movement of shell eggs and liquid eggs are addressed in separate risk assessments.

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The first step in our risk evaluation was to estimate the number of HPAI virus contaminated nest run eggs moved from an infected but undetected flock under the active surveillance protocol. This estimate is dependent on the HPAI spread characteristics within the flock as well as the time to detection of HPAI virus given the surveillance protocol. Simulation models of HPAI transmission within a flock and the impact of the active surveillance model were developed as part of a previous risk assessment for the movement of washed and sanitized eggs. In chapter 7, we summarize the relevant parameter estimates, results, and conclusions for the disease transmission and surveillance models from the washed and sanitized shell eggs risk assessment.4 In chapter 8, we evaluate the likelihood of egg packing materials moved from an infected but undetected nest run farm being contaminated with HPAI virus. Specifically, we evaluate potential pathways for contamination of materials through contaminated eggs, environment or personnel. We also estimate the viral titers on egg packing materials contaminated through these pathways. In chapter 9, we estimate the degree of HPAI virus inactivation on different types of egg packing materials from washing and disinfection procedures at the processing center. Next, in chapter 10 we evaluate the overall risk of egg packing materials leaving the processing center resulting in HPAI spread to other poultry premises. The impact of a waiting period of at least 24 hours before returning materials to the premises of origin as well as the cleaning and disinfection was considered in the risk evaluation. An evaluation of the risk of HPAI spreading to other poultry premises via the vehicle or driver leaving the processing center is presented in chapter 11. Finally, in chapter 12 we evaluate the risks for nest run farms that hand gather eggs.

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7. The Risk that HPAI Virus Contaminated Nest Run Eggs are Moved from an Infected but Undetected Premises

This section of the risk assessment describes the risk that nest run eggs leaving an infected but undetected premises are internally or externally contaminated with HPAI virus.

7.1 Background Information

In order to evaluate the risk of HPAI spread associated with movement of nest run eggs and associated egg packing materials, we first need to estimate the proportion of eggs moved from an infected but undetected flock that would be contaminated. Natural outbreak and experimental studies have found HPAI H5N2 virus in eggs laid by infected chickens.5-7 Although HPAI H5N1 was never found in eggs laid by infected chickens, we conservatively assumed that the virus could be present in such eggs in our evaluation. The proportion of contaminated eggs from an infected but undetected flock depends on the HPAI prevalence at various time periods before infection is detected. A characteristic feature of HPAI infection in a flock is the exponential increase in prevalence and mortality over time. Consequently, the proportion of contaminated eggs expected from an infected but undetected farm during an outbreak would depend on the time it takes to detect infection given the surveillance protocol followed during the outbreak. The Egg Movement Control Response plan for use in an HPAI outbreak specifies an active surveillance protocol based on RRT-PCR testing (Appendix 1).

Risk that HPAI Virus Contaminated Nest Run Eggs are Moved from an Infected

but Undetected Premises

• Risk Factors: Internal egg contents contaminated with HPAI virus; egg surface contaminated with HPAI virus; late detection of HPAI infection in a flock.

• Current Preventive Measures: none

• Additional Preventive Measures (to be implemented by industry in conjunction

with APHIS during an outbreak): Active surveillance of flocks for clinical signs of illness, changes in feed and water intake, drop in egg production, an increase in daily mortality above an established threshold, and submission of a pooled sample of swabs from 5 randomly chosen birds among the daily mortality for RRT-PCR testing taken daily during the outbreak; the EMC Response plan.

• Conclusions: The expected number of internally and externally contaminated

eggs moved per day from an infected but undetected 100,000 bird layer house is 11 (90 percent P.I. 0-44).

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Simulation models of disease transmission and the active surveillance protocol were developed as part of a previous proactive assessment for the risk of HPAI spread associated with the movement of washed and sanitized shell eggs.4 The transmission model simulates HPAI spread within the flock over time. The active surveillance protocol model then uses transmission model output to estimate the number of internally contaminated eggs that might be moved before infection is detected in the flock. The simulation model results from the washed and sanitized shell eggs risk assessment concerning the likelihood of moving contaminated eggs before infection is detected are also applicable for the movement nest run eggs. In this section, we summarize the relevant parameter estimates, results and conclusions from the disease transmission and surveillance models as described in the washed and sanitized shell eggs risk assessment.

7.2 Summary of Key Disease Transmission Model Parameter Estimates and Results

Table 1 summarizes the key parameters used in the disease transmission and active surveillance models. Details concerning the development of these parameters are fully described in the risk assessment for movement of washed and sanitized shell eggs. In brief, flock size, contact rate, mortality, egg production rate, and the sensitivity of surveillance tests were all considered in these models. The maximum daily number of internally contaminated eggs is primarily dependent on the duration of infection of the flock, and is predicted using the disease transmission and active surveillance models. The maximum daily number of externally contaminated eggs is more difficult to predict as contamination may occur from the oviduct when laying or from the environment. Given the multiple pathways for external contamination of eggs, we expected that the number of externally contaminated eggs would exceed the number of internally contaminated eggs. However, published data from flocks naturally or experimentally infected with avian influenza viruses indicate that the frequency of contamination of the eggshell is similar to or less than the frequency of internal content contamination:

• In a laboratory study, eggs from HPAI H5N2 infected hens exhibited a frequency of contamination of the eggshell similar to the frequency of internal content contamination.6

• In a natural outbreak study, eggs collected from HPAI H5N2 infected commercial layer hens had virus isolated from the albumen of 11/24 eggs, while virus was isolated from the shell surface of 2/22 eggs.5 Assuming that these data were obtained through random sampling, there is a 99 percent chance that the true proportion of externally contaminated eggs in this flock was less than the true proportion of internally contaminated eggs.g

• On LPAI H7N2 infected broiler breeder farms, virus was not found on 120 eggshell swabs, although virus could be isolated from 90 percent of chicken (tracheal or cloacal swabs) and 50 percent of dust and manure swabs.8

Given these observations, we assumed that the proportion of internally contaminated eggs is greater than the proportion of externally contaminated eggs. The model results on the number g The uncertainty associated with the true proportion of internally contaminated eggs was modeled as a Beta (12, 14) distribution. The uncertainty associated with the true proportion of externally contaminated eggs for this flock was modeled as Beta (3, 21) distribution.

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of internally contaminated eggs were used as a conservative estimate of the number of externally contaminated eggs, regardless of the source of external contamination. The disease transmission and active surveillance simulation model results are summarized in Table 2.

Table 1. Key parameter estimates for the HPAI transmission and surveillance models from washed and sanitized shell eggs risk assessment.9

Parameter Name Parameter Description Value

Effective contact rate (transmission parameter)

The number of birds an infectious hen comes into contact with that is sufficient to transmit infection per unit time

2 hens/6-hours

Expected latent period

The duration an HPAI infected bird is not infectious to susceptible birds

13.8 hours

Expected infectious period

The duration an HPAI infected bird is infectious to susceptible birds

29.58 hours

Expected time to death

Sum of the expected latent and infectious periods

43.38 hours

Basic Reproductive number (Ro)

The expected number of secondary infections caused by an infected hen in its lifetime

9.9

Normal egg production rate

Average egg production rate in layer hens that are not infected with HPAI virus

0.7 eggs/hen/day

Infected HPAI egg production rate

Estimated egg production rate during the period in which HPAI infected hens may lay contaminated eggs

0.49 eggs/hen/day

Flock size An estimate of the number of birds per henhouse currently in the industry

100,000 hens

Normal daily mortality per 100,000 chickens

Estimated normal mortality independent of HPAI infection

Empirical distribution Mean 28 birds/day; Std. Dev. 33 birds/day

Sensitivity of the RRT-PCR test

The probability that the RRT-PCR detects HPAI when a pooled sample with HPAI virus is tested

86.5 percent

Mortality threshold HPAI infection would be suspected regardless of RRT-PCR testing if the daily mortality exceeds this threshold percent of the flock

0.5 percent

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Table 2. Key results for the HPAI transmission and surveillance models from washed and sanitized shell eggs risk assessment. 9

Parameter Description Value

Maximum daily number of internally contaminated eggs that may be moved from an infected but undetected premises

11 (90 percent P.I. 0-44) eggs/dayh

Maximum daily number of externally contaminated eggs that may be moved from an infected but undetected premises

11 (90 percent P.I. 0-44) eggs/day

HPAI viral titer in the contents of contaminated eggs 104.5 EID50/mli

HPAI viral titer on the shell surface of contaminated eggs 103.6 EID50/eggshell

Number of days the flock is infected before HPAI infection is detected

3.23 (90 percent P.I. 2-5 days)

7.3 Conclusion

In this chapter, we utilized a probabilistic disease transmission model to estimate the number of HPAI virus contaminated nest run eggs from an infected but undetected layer flock following the active surveillance protocol described in the Egg Movement Control Response plan (Appendix 1). The key conclusions from this chapter are as follows.

a) Given an infected but undetected flock of 100,000 layers following the active surveillance protocol, • The expected number of internally contaminated eggs that may be moved per day

is 11 (90 percent probability interval 0-44). • The proportion of externally contaminated eggs with HPAI virus was assumed to

be similar to the proportion of internally contaminated eggs based upon data from naturally or experimentally infected hens. Given this assumption, the expected number of externally contaminated eggs moved per day is 11 (90 percent probability interval 0-44).

b) The viral titer in the internal contents of an egg laid by an infected hen was estimated to be 104.5 EID50/ml.

c) The viral titer on a contaminated eggshell was estimated to be 103.6 EID50/eggshell. In our analysis, RRT-PCR was considered as the sole means for detecting infection. However, in practice, clinical signs such as increased mortality, decreased egg production and supplemental PCR testing may lead to earlier detection. It is important to note that in an h A 90 percent probability interval (a,b) for a parameter X implies a 90 percent chance that the parameter value is within this interval i.e., P(a<X<b)=0.9. There is a 95 percent chance that the parameter value is less than b. i EID50 refers to the 50 percent chicken embryo infectious dose. On average, 50 percent of embryonating chicken eggs would become infected when exposed to a dose of 1 EID50.

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outbreak situation, deviation from modeling results is to be expected. This is likely because of the characteristics of the specific HPAI strain causing the outbreak (i.e. length of latently infected and infectious periods), variations in affected flock sizes, layer management practices, and other variables that cannot be captured or measured via modeling.

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8. Likelihood of Egg Packing Materials Moved from an Infected but Undetected Belt Gathered Premises Being Contaminated with HPAI Virus This section describes the likelihood of egg packing materials leaving an infected but undetected premises being contaminated with HPAI virus.

8.1 Overview In this chapter, we estimate the likelihood and number of HPAI-virus contaminated egg packing materials moved from an infected but undetected nest run farm through various pathways associated with contaminated eggs, personnel or environment. In addition, we estimate the degree of contamination of the materials through each of these pathways. The egg packing materials associated with nest run eggs include egg flats for holding the eggs, and supporting materials for stacks of egg flats such as pallets, nest run carts, racks, divider boards and tic-tacs. The potential pathways by which egg packing materials from an HPAI infected but undetected nest run farm may become contaminated are as follows:

Likelihood of Egg Packing Materials Moved from an Infected but Undetected

Belt Gathered Premises Being Contaminated with HPAI Virus

• Risk Factors: Egg surface contaminated with HPAI virus; internal egg contents contaminated with HPAI virus; leakage of egg contents onto packing materials; egg packing/storage area floors contaminated via personnel and equipment traffic from henhouse.

• Current Preventive Measures: Industry good manufacturing practices (GMPs).

• Additional Preventive (to be implemented by industry in conjunction with

APHIS during an outbreak): Active surveillance protocol for all flocks on the premises as specified in the EMC Response plan.

• Conclusion: We have the following conclusions regarding the likelihood of

contamination of egg packing materials through various pathways. o The maximum daily number of egg flats contaminated from egg surfaces and moved prior

to detection of infection is 11 (90 percent P.I. 0-44) o The maximum daily number of egg flats contaminated from egg contents and moved prior

to detection of infection is 0.18 (95 percent P.I. 0-1) o A small number of egg flats may be cross-contaminated from personnel or the

environment. o A small number of egg pallets or carts may be cross-contaminated from the floor of the

egg packing room or storage areas.

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Egg flats • Contact with contaminated egg surfaces • Leakage of contaminated egg contents

Cross-contamination from the environment or personnel Supporting materials (racks, pallets, divider boards, tic-tacs, nest run carts, etc.)

• Leakage of contaminated egg contents Cross-contamination from the environment or personnel

8.2 Evaluation of Risk

We performed the risk evaluation in three parts:

a) The likelihood and degree of contamination of egg packing materials from an infected but undetected farm through contact with contaminated egg surfaces.

b) The likelihood and degree of contamination of egg packing materials from an infected but undetected farm due to leakage of contaminated egg contents.

c) The likelihood and degree of contamination of egg packing materials via personnel or environment.

8.2.1 The Likelihood and Degree of Contamination of Egg Packing Materials from an Infected but Undetected Farm by Contact with Contaminated Egg Surfaces Egg flats are the only packing materials that contact the nest run eggs directly. The number of egg flats contaminated through this pathway would largely depend on the number of contaminated eggs produced. Although contaminated eggs could all originate from the same region of the henhouse, they may be packed onto different flats due to mixing in the handling system. We conservatively assumed that each contaminated egg is packed onto a different flat. Given this assumption, the number of contaminated egg flats is equal to the number of externally contaminated eggs. Based on results from chapter 7, the expected value of the maximum number of flats contaminated through direct contact with egg surfaces from an infected but undetected flock is 11 (90 percent P.I., 0-44) contaminated flats/day. Data that directly estimates the amount of HPAI virus transferred from a contaminated eggshell to a flat is not available. In a viral cross-contamination study with feline calicivirus, Bidawid et al. found viral transfer rates in the range of 6 to 46 percent between contaminated finger-pads and materials such as steel, ham and lettuce.10 Bean et al. reported less than 10 percent transfer of influenza A virus from a contaminated stainless steel counter top to hands.11 Other studies on viral transfer rates between finger pads and other surfaces found similar transfer rates (details are provided in Appendix 12). Assuming that 6-46 percent of the virus on an egg is transferred to an egg flat on which it is placed, we estimated that103.0

(102.7 -103.3) EID50 of HPAI virus might be transferred onto the flat. There is considerable uncertainty in this estimate given the lack of direct data on the HPAI virus transfer rate between eggshells and flats.

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8.2.2 The Likelihood and Degree of Contamination of Egg Packing Materials from an Infected but Undetected Farm due to Leakage of Contaminated Egg Contents The number of flats contaminated from egg contents primarily depends on the number of internally contaminated eggs leaking during packing or transportation. Direct data on the percent of “leakers” (eggs with missing or damaged shell and ruptured shell membrane) in normal, virus-free nest run eggs in the time interval during which they are packed on egg flats is not available. Industry experts indicated 0.25 to 1 percent of eggs might be leakers when they are collected at nest run farms depending on the age of the flock.j However, by this stage most leakers would have been removed after visual inspection of the eggs before being packed on to flats. We conservatively assume that only half of leakers are removed as inedible eggs before being packed onto flats, resulting in a 0.13-0.5 percent of leakers. Lederer et al. found that an additional 0.18 percent of eggs became leakers during transportation to the market.12 Based upon Lederer et al., we assumed that an additional 0.16-0.22 (Appendix 8.1) percent of the eggs would become leakers during transportation. Overall, we estimated that 0.5 (90 percent P.I., 0.33-0.67) percent of normal virus-free nest run eggs received at an off-line processing center would be leakers.

HPAI virus contaminated eggs are more likely to be defective and thus may have a higher fraction of leakers compared to normal eggs. Based on an expert opinion panelk, we estimated that HPAI virus contaminated eggs with no visual defects are 3.7 (90 percent P.I. 2.2-7) times more likely to leak than virus-free eggs. We estimated that 1.8 (90 percent P.I. 0.8-3.7) percent of HPAI virus contaminated nest run eggs received at an off-line processing center would be leakers (Appendix 8.1). We calculated the number of HPAI virus contaminated leaking eggs from an infected but undetected flock through a simulation model that combines the estimated number of HPAI contaminated eggs (from chapter 7) with the estimated proportion of HPAI contaminated eggs that leak from above. Six thousand iterations of this model were run using @RISK13. The expected number of HPAI virus internally contaminated leaking eggs from the simulation results was 0.18 (95 percent P.I. 0-1) (details are provided in Appendix 8). The simulation results also show none of the contaminated eggs moved from an infected but undetected flock would leak in the majority of cases (90 percent of the iterations). In rare instances, contaminated egg contents may also leak onto supporting egg packing materials (divider boards, tic-tacs, pallets and carts). From chapter 7, the estimated HPAI viral titer in the egg contents is approximately 104.5 EID50/ml.

j Estimates from industry representatives (Pat Stonger, Daybreak Foods) and personal communication (Dr. David Halvorson, University of Minnesota), 2009. k Details included as Appendix 7.

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8.2.3 The Likelihood and Degree of Contamination of Egg Packing Materials via Personnel or Environment

8.2.3.1 Cross-contamination via Personnel Egg packing materials may become contaminated when they are handled by personnel who have contacted contaminated eggs earlier in the day. For instance, personnel removing cracked, leaking or other defective eggs (“checks”) could also stack egg flats onto a pallet. In normal operations, 2-5 percent of the eggs may be checks.14 HPAI virus contaminated eggs are more likely to be defective. Beard et al. reported that 3 out of 15 HPAI virus contaminated eggs laid by experimentally inoculated hens were soft-shelled.7 We estimated that 2.5 (90 percent P.I. 0-9) eggs from an infected but undetected flock of 100,000 layers might be soft-shelled based on Beard et al., data (see Appendix 8.2 for details). Therefore, a small number of egg flats or pallets could become contaminated via hands of personnel who have previously contacted defective contaminated eggs as they remove them from the packing line. The viral titer on materials contaminated through this pathway would be lower when hands of personnel are contaminated through contact with egg surfaces rather than egg contents. Studies of influenza A virus and feline calicivirus showed less than 15 percent of virus was transferred from surfaces such as steel, lettuce and ham to fingers pressed onto them.10,11 In the reverse direction, Bidawid et al. found up to 46 percent virus transfer from finger pad to ham.10 Assuming the above cross-contamination rates, the amount of virus transferred from a contaminated eggshell (estimated viral titer 103.6 EID50/egg shell) through hands to a flat is 102.4 EID50. In the few instances where egg packing materials may become contaminated through personnel who have contacted contaminated egg contents, we assumed that the viral titer on the materials is similar to that in contaminated egg contents.

8.2.3.2 Cross-contamination via Environment Egg packing materials could potentially be cross-contaminated through packing or cooler room floors, or from henhouse aerosols.

(i) Likelihood of contamination of egg packing materials through packing or cooler room floors.

Egg processing plant studies indicate that floors can serve as reservoirs for microbial contamination, particularly in areas with frequent personnel movements.15,16 Pearson et al, reported that several samples from the egg belt, egg room floor, and egg flats were positive for HPAI virus during the 1983 HPAI H5N2 outbreak in the U.S.17 Therefore, it is possible for the egg packing room floors of infected premises to become contaminated through personnel movements from the henhouse. According to egg industry experts, larger farms would have a greater division of duties with most personnel dedicated to either henhouse related duties or egg packing operations. In this case, packing or cooler room floors would be less likely to become contaminated due to personnel traffic from the henhouse. In general, the likelihood that egg packing materials are contaminated through this pathway at an

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infected but undetected premises would be minimized when the active surveillance protocol is followed. Simulation results of the disease transmission model indicate that HPAI virus would be detected before 0.5 (90 percent P.I. 0.016-2.6) percent of the flock transitions to an infectious state.

(ii) Degree of contamination of egg packing materials through packing or cooler room floors.

To estimate HPAI viral titer on egg packing materials contaminated through this pathway, we first estimated the HPAI viral titer in the henhouse floor dust. We then estimated the amount of HPAI virus contaminated dust transmitted into egg packing or storage area floors via movements of personnel and subsequently transferred onto egg packing materials.

We estimated the HPAI viral titer in dried dust settled on the henhouse floor using two alternate approaches as follows. Approach 1: Air sampling studies during the 2004 HPAI H7N7 outbreak in Canada found a viral titer of approximately 103.4 EID50/m3

in the air inside a severely infected caged layer type henhouse.18 The airborne particle concentration in a layer house is typically less than 2 mg/m3.19-22 Assuming that the airborne particle concentration in the layer barns sampled during the Canadian outbreak was 2 mg/m3, and assuming that the viral titer/g of airborne particles is the same as the viral titer in dust settled on the henhouse floor, the viral titer in the dust accumulated on a henhouse floor would be 103.4 EID50/m3

/(2×10-3 g/m3) = 106.1 EID50/g. Approach 2: The HPAI viral titer in fresh chicken manure may range from 103.5 -107 EID50/g depending on the strain of the virus.23 In a typical caged layer house, most of the manure is transferred to a manure pit through a handling system. The dust that settles on the layer house floor likely originates from multiple sources such as feed, feathers, skin squames and manure. Hartung and Saleh reported that 80-90 percent of particle dust in broiler operations is from feed.24 Assuming a similar proportion of feed in the dust particles in a layer house and conservatively assuming that the remainder of the particles (10-20 percent) have a viral titer similar to that in moist chicken manure, the HPAI viral titer in the dust accumulated on the henhouse floor would be 0.7-1 log EID50 lower than the viral titer in the manure. Hence, based on this approach, an approximate range for the viral titer in the dust accumulated on the henhouse floor is 102.5-106.3 EID50/g. In summary, an approximate range for the HPAI viral titer in dried dust settled on the henhouse floor based on the above approaches is 102.5-106.3 EID50/g. Impact of drying: In caged layer houses, the floor areas which personnel might walk through are more likely to have dried dust and/or fecal material rather than fresh wet feces. HPAI viruses are fairly sensitive to drying depending on the temperature, with more than a 4 log reduction (10,000 fold) in the viral titer occurring with one day of drying at 25°C.7,25 However, the virus may survive in dried feces for more than 9 days at 4°C.26,27 Lu et al. found that 50 percent of environmental dust swabs (from fans, heater or walls) from LPAI

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H7N2 infected henhouses were contaminated.8 This study indicates that influenza viruses may persist at some low viral titers even in dried environmental dust from henhouses.l The next steps in our evaluation were to estimate the amount of HPAI virus contaminated dust transferred to the egg packing or storage area floors and then subsequently transferred onto egg packing materials. Direct data on the quantity of dust adhering to personnel shoes in a henhouse or viral transfer rates between relevant surfaces (shoes to floor, floor to packing materials, etc.) are not available. We evaluated this pathway through scenario analysis using experimental data on the adherence of soil to shoes,28 the transfer rates of various viruses between inanimate surfaces and finger pads, and expert opinion regarding the viral transfer rates between relevant surfaces encountered in the poultry environment. Experimental viral transfer rates between various inanimate surfaces and finger pads ranged from 6 to 46 percent.11 Virology experts stated that 40 percent is a conservative value for the viral transfer rates between surfaces such as shoes to concrete floor and floor to wooden pallets (SA Sattar, pers. comm. March 2010). Soil track in experiments indicated that less than 2 grams of dried soil may adhere to the shoe of a person standing on a dusty surface.10,28,29 Given the high degree of uncertainty, we evaluated this pathway using scenario analysis. We considered a baseline scenario and a conservative scenario in our analysis (details are provided in Appendix 12). In the baseline scenario, we estimated a viral titer of 100.6 EID50/cm2 on contaminated egg packing materials given the two transfer steps in this pathway (shoes to floor and floor to packing materials). This virus titer is fairly low and can be effectively inactivated with cleaning and disinfection. In the conservative scenario, the estimated viral titer on egg packing materials contaminated was 102.9 EID50/cm2

. The viral titers estimated in the scenarios mentioned above are only indicative of an approximate range given the lack of direct data on viral transfer rates on surfaces encountered in the poultry environment. In summary, it is possible for egg packing materials to be contaminated from the packing room or cooler room floor, which becomes contaminated from personnel traffic from the henhouse. The viral titer in the dust accumulated on the henhouse floor is expected to be lower than that in contaminated manure due to mixing with virus-free material such as feed. In addition, since only a fraction of virus present on a surface is transferred to surfaces that are in direct contact with it, the surface viral titer on egg packing materials contaminated through this pathway is expected to be lower than that of the shoes of personnel who have walked across contaminated areas of the henhouse. There is considerable uncertainty regarding this pathway. Scenario analysis suggests the viral titer on egg packing materials contaminated through this pathway may range between 100.6 -102.9 EID50/cm2. (iii) Likelihood and degree of contamination of egg packing materials via HPAI virus contaminated henhouse aerosols.

l There are two approaches to interpreting the results from this study. If the viral titers in different dust samples are similar, the results indicate a low viral titer of 1 EID50/swab that is unlikely to be infectious to a chicken. As an alternate explanation, the environmental samples could be from different regions with very high or very low viral titer.

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In mechanically ventilated henhouses, the henhouse is maintained at a negative air pressure relative to the egg packing or storage rooms. In this case, there is limited opportunity for packing materials in the egg storage area to become contaminated via aerosols from the henhouse. A 1999 survey found that more than 70 percent of henhouses are mechanically ventilated.30 In naturally ventilated henhouses without positive air pressure into the packing room, there is a possibility that aerosols from the henhouse could access the egg packing room and contaminate egg packing materials. To evaluate the likelihood and degree of contamination of egg packing materials via aerosols from naturally ventilated henhouses, we considered the following factors:

• It is unlikely that there is significant airflow from henhouses into egg packing and storage areas even in naturally ventilated henhouses. This is because henhouse doors are usually kept closed when not in use. In addition, openings for egg conveyer belt are typically designed to closely match the belt dimensions so that airflow from the henhouse is minimized. Given the relatively minor quantity of airflow into the egg packing room from the henhouse, the HPAI viral titer in the egg packing rooms would be substantially diluted compared to the viral titer in henhouse air.

• When the active surveillance protocol is followed, HPAI infection in the flock is

likely detected before a significant portion of the flock is infected. Simulation results of the disease transmission model indicate that HPAI virus would be detected before 0.5 (90 percent P.I. 0.016-2.6) percent of the flock transitions to an infectious state. Given the small fraction of infected hens in the flock, the HPAI virus concentration in the air flowing into the egg packing room would be diluted relative to the HPAI concentration in the air near infected cages.

• A study by Maghirang et al. found 97 percent of particles in henhouse to be less then

5 µm in size.31 These particle sizes would settle at a slow rate (a settling time of 20 minutes or more per 1 meter fall), minimizing the amount of particles deposited onto egg packing materials as they move through the packing room to the storage or cooler rooms.

Based on the above, we conclude that the likelihood of egg packing materials in an infected but undetected premises being contaminated via aerosols from the henhouse is negligible when the henhouses are mechanically ventilated. We conclude that the likelihood of egg packing materials being contaminated via aerosols from an infected but undetected flock is low for premises with natural ventilation. The degree of contamination of egg packing materials via aerosols is likely low considering the small fraction of infectious hens before HPAI is detected and the dilution of viral titer due to mixing of henhouse air and the egg packing room air.

8.3 Conclusion

In this chapter, we evaluated the likelihood and degree of contamination of egg packaging materials from an infected but undetected premises through pathways associated with HPAI

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contaminated eggs, personnel or the environment. The key conclusions from this chapter are as follows:

a) Regarding direct contamination of egg packing materials from egg surfaces or contents:

• The expected maximum number of egg flats per day that are contaminated with HPAI virus from the surface of eggs packed in them and moved before infection is detected in the flock is 11 (90 percent P.I. 0-44). The amount of HPAI virus transferred to the flat through contact with a contaminated egg surface was estimated to range from 102.7 to 103.3 EID50.

• The expected value of the maximum number of egg packing materials per day that are contaminated with HPAI virus from the contents of leaking eggs and moved before infection is detected is 0.18 (95 percent P.I. 0-1). The HPAI viral titer of the egg contents on the flats is expected to be similar to the titer in contaminated egg contents of 104.5 EID50/ml.

b) Regarding contamination of egg packing materials through personnel: • A small number of egg packaging materials may become contaminated when

they are handled by personnel who have contacted contaminated eggs earlier in the day. An approximate estimate of the amount of HPAI virus transferred onto an egg packaging material through this pathway is 102.4 EID50.

• In rare instances, egg packaging materials may become contaminated from personnel who have contacted contaminated leakers. The titer on the materials contaminated through this pathway is expected to be the same as that in contaminated egg contents.

c) Regarding cross contamination of egg packing materials from the environment:

• A small number of egg packing materials may become contaminated from the floor of the packing or cooler rooms which became contaminated from movements of henhouse personnel. Scenario analysis indicates that the viral titer on egg packing materials contaminated through this pathway may range between 100.6 -102.9 EID50/cm2.

• The likelihood of egg packing materials being contaminated via aerosols from the henhouse is negligible for premises with mechanical ventilation. For premises with natural ventilation, the likelihood of likelihood of egg packing materials being contaminated via aerosols from the henhouse is low.

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9. Likelihood of HPAI Virus on Egg Packing Materials after Cleaning and Disinfection This section addresses the risk that HPAI virus on contaminated egg packing materials is not inactivated by the cleaning and disinfection procedures at the off-line processing center.

9.1 Overview

Avian influenza viruses have been shown to survive for multiple days on common egg packing materials such as plastic and wood.11,32,33 However, due to their lipid envelope, these viruses show marked sensitivity to disinfection agents and lipid solvents such as detergents.34,35 The ability of disinfectants to inactivate avian influenza viruses in part depends on the target surfaces: hard, nonporous surfaces such as plastic provide ideal exposure of virus to disinfectant and virus inactivation is relatively efficient. For porous substances, it is relatively harder to experimentally demonstrate virus inactivation with a disinfectant due to inconsistent virus recovery from the pores. In this chapter, we describe the current cleaning and disinfection procedures practiced in the industry as well as the model cleaning and disinfection procedures for egg packing materials that would be implemented in an HPAI outbreak. Due to the more standardized nature of the planned cleaning and disinfection protocols that will be implemented during an outbreak as specified in the Egg Movement Control (EMC) Response plan, our risk evaluation focuses on these measures.

Likelihood of HPAI Virus on Egg Packing Materials after

Cleaning and Disinfection

• Risk Factors: High HPAI viral titer on contaminated egg packing materials. • Current Preventive Measures: Cleaning and disinfection of egg flats practiced

by some egg processing operations.

• Additional Preventive Measures (to be implemented by industry in conjunction with APHIS during an outbreak): Use of disposable materials, or cleaning and disinfection of egg packing materials as specified in the EMC Response plan and the Model Cleaning and Disinfection Guidelines.

• Conclusion: The likelihood of viable HPAI virus remaining on hard nonporous

egg packing materials after cleaning and disinfection is negligible. The likelihood of viable HPAI virus remaining on porous egg packing materials after cleaning and disinfection is low.

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9.2 Preventive Measures

9.2.1 Current Preventive Measures Current preventive measures are aimed at preventing bacterial contamination of packing materials. The USDA APHIS Layer 1999 survey found that the majority (71 percent) of nest run farms used plastic flats that were cleaned and disinfected between uses.1 A smaller fraction of the operations washed or disinfected other supporting materials such as divider boards and pallets. Approximately 29 percent of the operations also returned the pallets, divider boards and nest run carts to the farm of origin.1 The specific implementation of these preventive measures varies among different operations.

9.2.2 Preventive Measures in the Event of an HPAI Outbreak The future preventive measures evaluated in this assessment are those specified in the EMC Response plan to be implemented in the event of an HPAI outbreak. In this plan, egg packing materials must either be disposed of at the destination off-line processing center or cleaned and disinfected and returned to the farm of origin. The EMC Response plan contains cleaning and disinfection procedures for vehicles, equipment and materials employed in the movement of eggs and egg products. The portions of the cleaning and disinfection procedures pertaining to egg handling materials utilized in the movement of nest run eggs are included in Appendix 2. In the following, we summarize the procedures for cleaning and disinfection of egg packing materials.

9.2.2.1 Procedures for Mechanical Washing and Disinfection of Nonporous Materials �• Washable flats, pallets and dividers are introduced into the washing system after

performing preoperational checks. • EPA registered disinfectants with label claims against avian influenza are recommended.

The disinfectant should be mixed according to the manufacturer’s directions and applied for the recommended contact time.

• The temperature of wash and rinse waters, detergent and disinfectant concentrations, and condition of wash water for excessive foaming and build-up of egg must be recorded in an operating log.

• The wash water temperature must be at least 90°F. • Cleaned and disinfected materials are visually inspected. The cleaning and

disinfection cycle must be repeated if there is adhering egg or organic soil. • Wash water tank must be drained and cleaned at mid-shift.

9.2.2.2 Procedures for Manual Cleaning and Disinfection of Wood Based (Porous) Egg Packing Materials �

• The temperature of wash and rinse waters, detergent and disinfectant concentrations must be recorded in an operating log.

• Accumulated organic matter and soil must be dry cleaned by brushing or scraping. • The materials must be washed with a detergent solution using brushes or a high-

pressure washer and rinsed with clean water. • The material must be inspected for cleanliness and rewashed if not clean. • The sanitizing solution must be applied to the material and allowed to dry.

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We evaluated the risk of HPAI virus being present on nest run egg packing materials after cleaning and disinfection in two parts.

a) Risk of HPAI virus being present on egg packing materials after washing.

b) Risk of HPAI virus being present on egg packing materials after disinfection.

9.3.1 The Risk of HPAI Virus Being Present on Egg Packing Materials after Washing The purpose of the wash step is to remove organic material from the egg packing materials so that disinfectant can be effectively applied. Avian influenza viruses are very sensitive to detergents due to surfactant action on the lipid envelope.36,37 The effectiveness of the detergent in inactivating virus depends on the operational conditions such as temperature, organic load and contact time. We evaluate the degree of HPAI virus inactivation following the washing procedures described in the Model Cleaning and Disinfection Guidelines based upon published literature and expert opinion. Table 3 summarizes relevant studies concerning the inactivation of influenza A viruses with soap or detergent. These data indicate that soap or laundry detergent solutions can inactivate influenza virus on hard nonporous substances by 3 logs (1000 factor reduction in the viral titer) with contact times varying between one to ten minutes. Data on the inactivation of influenza viruses on porous substances is limited given the experimental difficulties associated with virus recovery from these substances. Data from Lombardi et al. suggests that laundry detergent with peroxide causes a 0 to 2 log inactivation of LPAI virus on wood.38 A panel of experts on the physical and chemical inactivation of HPAI virus indicated that washing with a detergent at a temperature greater than 90°F would likely result in 1.5 to 4 log reduction of HPAI viral titer on plastic materials and 0 to 2 log reduction on wooden materials (Appendix 7). The degree of HPAI virus inactivation with washing procedures described in the EMC Response plan depends on specific operational parameters. The Model Cleaning and Disinfection Guidelines require the wash water temperature to be higher than 90°F. The requirement to replace wash water mid-shift is intended to control the organic load. Other parameters such as contact time may vary among operations. Overall, we estimated that there will be a 1 to 3 log inactivation of avian influenza virus on plastic egg packing materials and a 0 to 2 log inactivation on wooden egg packing materials with the washing procedures described in the Model Cleaning and Disinfection Guidelines.

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Table 3. Summary of studies of detergent action on avian influenza viruses.

Study, virus and substrate

Detergent formulation

Experimental conditions Log reduction in viral titer

Alphin et al 2009; LPAI H7N7 on steel coupons39

2-6 g/L of laundry detergent without bleach

Contact time 10 minutes; Hard water solution of 400mg calcium carbonate/L

3-4

Shahid, et al. 2009 HPAI H5N1 suspension of 4 HAm units40

0.1 percent soap; 0.1 laundry detergent solution

Contact time 5 minutes 3 with both soap and laundry detergent

Grayson et al. 2009; H1N1 104 TCID/ml on volunteer’s hands41

Non medicated hand soap

Washing with soap and tap water for 40 seconds.

3

Lombardi et al. 2009; LPAIV H7N2 on wood and plastic coupons38

2-6 g/L of laundry detergent with peroxide

Contact time 10 minutes; Hard water solution of 400mg calcium carbonate/L

Plastic: 2.5-5 Wood: 0-2

9.3.2 The Risk of HPAI Being Present on Egg Packing Materials after Disinfection

9.3.2.1 Degree of HPAI Virus Inactivation on Plastic Egg Packing Materials with Sanitization/Disinfection. As described previously, the Model Cleaning and Disinfection Guidelines require following manufacturer label directions for the disinfectant with preoperational checks and monitoring of disinfectant concentration, temperature and contact time. In addition, the Model Cleaning and Disinfection Guidelines recommend using an EPA registered disinfectant with label claims against AI virus. The EPA maintains a list of registered disinfectants with label claims against avian influenza virus (Appendix 4) 42. The label claims must be supported by efficacy data that demonstrate a 3 log reduction on applicable surfaces. Additionally, the data must be generated in GLP (Good Laboratory Practicesn) certified laboratories, utilizing agency-accepted protocols. Details concerning the nature of the various EPA registered virucides, registration requirements, efficacy testing and samples of virucide testing tables are included as Appendices 4-6. Most EPA registered disinfectants require a contact time of ten minutes for AI virucidal uses. Experimental studies show that several categories of disinfectants such as organic acids,

m Hemagglutination Units n 40CFR160

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alkalis, detergents and phenols can obtain a 3 log inactivation of HPAI virus on hard nonporous substances with a contact time of 10 minutes.38,39,43,44 Avian influenza virus experts indicated that using an EPA registered AI virucidal disinfectant according to the label directions would likely result in 3.5 (90 percent P.I. 2-5) log inactivation of HPAI viral titer on hard nonporous substances (Appendix 7). In summary, given EPA efficacy data requirements, experimental data from the literature, and expert opinion, we conclude that using an EPA registered disinfectant according to manufacturer label directions for AI virucidal uses would result in a 3-log reduction of avian influenza virus on hard nonporous substances.o

9.3.2.2 Degree of HPAI Virus Inactivation on Wood Egg Packing Materials with Sanitization/Disinfection Given the challenges associated with inconsistent virus recovery from porous surfaces, to date there are no EPA registered disinfectants with label claims against avian influenza virus for these surfaces. Experimental data on the chemical inactivation of viruses on porous surfaces is limited. A recent study, Lombardi et al. found a 3 log inactivation of LPAI H7N2 virus on wood with citric acid and iodine/acid disinfectants.38 In this study, a 2 log inactivation of virus was reported for other agents such as calcium hydroxide and acetic acid. There is some ambiguity on whether the lack of virus recovery was due to disinfectant action, as no virus was recovered from three of the nine positive controls. Concurring with this study, an expert on inactivation of viruses also stated that organic acid disinfectants might be effective for enveloped viruses on porous surfaces (VS Springthorpe, pers. comm. March 2010).

A panel of avian influenza virus experts indicated that wooden surfaces disinfected with an EPA registered disinfectant against AI viruses would likely result in a 2 (90 percent P.I. 1 to 3.5) log inactivation of the virus (Appendix 7). Overall, considering the results from Lombardi et al. and the expert opinion, we conclude that using an EPA registered disinfectant for avian influenza virus on porous (e.g., wood) egg packing materials would result in a 2 (90 percent P.I., 1 to 3) log inactivation of HPAI virus.

9.3.3 Overall Impact of Washing and Disinfection of Egg Packing Materials

9.3.3.1 Nonporous Egg Packing Materials As discussed in chapter 8, contamination of egg flats mostly occurs through direct or indirect contact with HPAI virus present on the egg surfaces. A conservative estimate of the viral titer on egg flats contaminated in this way is 103.3 EID50/egg flat (chapter 8). On plastic materials, this viral titer would be effectively inactivated with washing (1 to 3 log reduction with detergent action) followed by a 3 log reduction obtained via disinfection with an appropriate EPA registered disinfectant against avian influenza.

o Some of the egg packaging materials such as egg flats are considered to be food contact materials (Julie Mayer, personal communication). Therefore, the disinfectants for egg flats must be used in accordance with applicable FDA regulations

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In the few cases where egg contents leak onto flats or supportive materials, the viral titer of the adhering egg would be approximately 104.5 EID50/ml. However, any visible egg or organic soil on the materials would be removed in the course of the washing and visual inspection processes as specified in the Model Cleaning and Disinfection Guidelines. To our knowledge, data on the residual amount of egg on materials after washing is not available. Based on a pilot experiment, an expert indicated that the thickness of a potential layer of egg remaining on the material would at most be 1 mm. Assuming that the viral titer in a layer of egg remaining on the material is the same as that in contaminated egg contents, the surface viral titer on the material (without considering the inactivation due to detergent) would be approximately 103.5 EID50/cm2. This viral titer would be inactivated with the more than 4 log inactivation on nonporous materials due to cleaning and disinfection as specified in the Model Cleaning and Disinfection Guidelines.

In summary, we conclude that HPAI virus on contaminated hard nonporous egg packing materials would be effectively inactivated by washing and disinfection with an EPA registered disinfectant for avian influenza as recommended by the Model Cleaning and Disinfection Guidelines.

9.3.3.2 Porous Egg Packing Materials For porous egg packing materials (i.e. wood), we estimated a 1 log EID50 (90 percent P.I. 0-2) inactivation of HPAI viral titer with the washing process and a 2 log EID50 (90 percent P.I. 1-3) inactivation with the use of an EPA registered AI disinfectant. Overall, with washing and disinfection combined, we estimated a 57 percent chance of more than 3 log inactivation of HPAI virus on wood (Appendix 9). However, we estimated a 13 percent chance of less than 2 log EID50 inactivation of HPAI virus on wood. Given these estimates, any indirect contamination of wood egg packing materials from HPAI virus on the egg surfaces (estimated viral titer of 101.76 EID50/cm2) p is expected to be effectively inactivated.

In the few instances where egg contents leak onto wooden materials, as described in section 9.3.3.1, we estimated the surface viral titer due to a residual layer of egg on the material to be 103.5 EID50/cm2. We expect this viral titer to be effectively inactivated (to less than 0.1 EID50/cm2) in the majority of the cases. However, for wooden packing materials contaminated with HPAI virus from egg contents, given the uncertainties associated with disinfecting porous materials, it is possible that a low level of residual contamination remains on some of the materials. Assuming that contents from one contaminated leaking egg contaminates one wooden packing material (a pallet, divider board or shelf of nest run cart) and the expert opinion regarding viral inactivation with cleaning and disinfection, the expected number of porous packing materials from an infected but undetected farm that are contaminated with HPAI virus from egg contents and inadequately disinfected (viral titer higher than 0.5 EID50/cm2) is 0.081(90 percent P.I 0-1). Details concerning the preceding estimate are provided in Appendix 9.

As discussed in chapter 8, a small number of wooden pallets may also become contaminated from the floor of the egg packing or storage room. Scenario analysis from chapter 8 indicated p Viral titer on contaminated egg surfaces was estimated to be 103.6 EID50/egg shell in chapter 7. Assuming an egg shell surface area of 68cm2 from Paganelli et al., 1974, the viral titer per cm2 of egg surface is 101.76 EID50.

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that the viral titer on egg packing materials contaminated through this pathway may range between 100.6 -102.9 EID50/cm2. We estimated a 95 percent chance that cleaning and disinfection would effectively inactivate (viral titer lower than 0.5 log EID50/cm2) HPAI virus on porous egg packing materials contaminated in this manner (Appendix 9.3).We conclude that HPAI virus on wooden egg packing materials contaminated from the egg packing or storage room floors is likely inactivated via cleaning and disinfection.

9.4 Conclusion In this chapter, we estimated the degree of HPAI virus inactivation obtained by washing and disinfecting egg packing materials following the recommendations of the Model Cleaning and Disinfection Guidelines included in the EMC Response plan. The key results from this chapter are as follows:

• The HPAI virus on contaminated hard nonporous egg packing materials such as

plastic would be effectively inactivated by washing with a detergent, and disinfecting with an EPA registered disinfectant for avian influenza as recommended in the Model Cleaning and Disinfection Guidelines.

• There is considerable uncertainty associated with the effectiveness of disinfectants against avian influenza viruses on porous substances due to the experimental difficulties associated with virus recovery from them.

• For porous egg handling materials such as wood:

o The washing and disinfection process as specified in the Model Cleaning and Disinfection Guidelines would result in a 3 log (1000 factor) inactivation of HPAI viral titer on the materials in the majority of the cases. However, based on expert opinion, we estimated a 13 percent chance of less than 2 log (100 factor) inactivation of HPAI virus.

o Indirect contamination of wooden egg packing materials from HPAI virus on

egg surfaces is expected to be effectively inactivated.

o In the few cases where egg contents might leak onto wooden materials, the HPAI virus is expected to be effectively inactivated in most cases. A low level of residual contamination may remain on the materials after disinfection in a small fraction of cases. The expected number of porous packing materials from an infected but undetected farm that are contaminated with HPAI virus from egg contents and inadequately disinfected (viral titer higher than 0.5 EID50/cm2) is 0.081(90 percent P.I 0-1).

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10. Risk of Egg Packing Materials Leaving the Processing Center Resulting in HPAI Spread to Other Poultry Premises This portion of the risk assessment describes the risk that HPAI virus contaminated egg packing materials moved from an off-line processing center to a belt-gathered nest run premises would result in HPAI spread to susceptible poultry. The risk evaluation for hand gathered nest run premises is presented in chapter 12.

10.1 Introduction As discussed in chapter 9, the washing and disinfection of egg packing materials according to the Model Cleaning and Disinfection Guidelines (included in the EMC Response plan) is expected to effectively inactivate any HPAI virus on contaminated egg flats and other nonporous materials. Even for wooden materials, the washing and disinfection procedures are expected to effectively inactivate HPAI virus in the majority of cases. The Movement Control Model plan contains further preventive measures designed to reduce the risk of HPAI spread to other poultry premises via contaminated egg packing materials. Specifically, the movement control plan requires the materials to be returned to the premises of origin after at least 24 hours have passed. This allows enough time for the confirmation of negative RRT-PCR tests results from the two most recently submitted samples for all the flocks on the premises. Furthermore, the cleaned and disinfected materials are not allowed to contact materials going to other premises. The Model Cleaning and Disinfection Guidelines require the cleaning and disinfection of the loading dock, storage areas, and the connecting passages after unloading nest run eggs from an HPAI control areaq. This helps prevent cross- q Poultry premises outside of the HPAI control area without clinical signs of infection and epidemiological links with infected premises are unlikely to be infected. The formal definitions for various responses zones within the control area and the designation of premises are provided in the EMC Response plan (Appendix1).

Risk of Egg Packing Materials Leaving the Processing Center Resulting in HPAI Spread to Other Poultry Premises

• Risk Factors: HPAI virus on egg packing materials not completely inactivated

with cleaning and disinfection procedures; Contaminated egg packing materials cross-contaminate new or cleaned and disinfected materials; Egg packing materials inadvertently returned to a premises other than the premises of origin.

• Current Preventive Measures: Industry good manufacturing practices (GMPs).

• Additional Preventive Measures (to be implemented by industry in conjunction

with APHIS during an outbreak): Egg packing materials must be returned to the premises of origin after at least 24 hours have passed to allow time for including the 2 most recent negative RRT-PCR tests for all flocks on the premises. Materials must not contact materials going to other premises.

• Overall Risk: low

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contamination of cleaned and disinfected materials from the floor of the egg packing or storage areas.

We note that there is a possibility that the above measures will not be implemented correctly due to procedural errors. For instance, egg packing materials may inadvertently be sent to premises other than the premises of origin because of errors in the material tracking processes. As mentioned previously, evaluation of the risk of the preventive measures not being correctly implemented is beyond the scope of this risk assessment. In the following, we evaluate the risk of HPAI spread to other poultry premises via contaminated egg packing materials when preventive measures outlined in the EMC Response plan are strictly followed. In addition, we briefly discuss the maintenance of egg packing material identity from an implementation standpoint.


We evaluated the risk of HPAI spread to other poultry premises via contaminated egg packing materials in two parts: a) Likelihood that egg packing materials contaminated prior to cleaning and disinfection are returned to the nest run farm before HPAI infection is detected. b) Risk that contaminated egg packing materials leaving the off-line processing center result in HPAI spread to susceptible poultry.

10.2.1 Likelihood that Egg Packing Materials Contaminated Prior to Cleaning and Disinfection are Returned to the Nest Run Farm Before HPAI Infection is Detected

The EMC Response plan requires that materials not be returned to the premises of origin until at least 24 hours have passed, allowing for confirmation of negative RRT-PCR tests results from the two most recently submitted samples for all flocks on the premises. This 24 hour time lapse results in an increased likelihood that active surveillance will detect HPAI infection at the premises of origin before materials are moved from the processing center. If HPAI infection is detected, we assume that the materials from the infected premises will be disposed of and thus not pose additional risks due to their movement.45 This preventive measure acts as additional mitigation in the event of a failure in material tracking resulting in the movement of egg packing materials to a nest run farm other than the farm of origin. To quantify the impact of the 24 hour time lapse before the return of packing materials, we first estimated the number of contaminated egg packing materials that would be transported from the processing center to nest run farms. For this purpose, we modified the simulation model of the active surveillance protocol from washed and sanitized shell egg risk assessment to include two RRT-PCR test results9. For comparison, we also performed a simulation including one RRT-PCR test result. Inactivation of virus due to cleaning and disinfection was not considered in these simulations.

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We performed 6,000 iterations of simulation with @RISK® (version 4.5.3) and Excel. For egg packing materials directly contaminated with HPAI virus from contact with contaminated egg surfaces (egg flats), the simulation results show a significant reduction in the expected number of contaminated egg flats that would be returned to nest run farms before HPAI infection is detected when two negative RRT-PCR test results are obtained before their movement (Table 4).

Table 4: Estimated number, variability, and maximum of HPAI virus contaminated egg flats moved per day from the processing center, under two RRT-PCR testing schemes.

For egg packing materials contaminated with HPAI virus from leaked egg contents, in conjunction with the 24 hour waiting period for results of two RRT PCR tests, there is a 98 percent chance of detecting HPAI infection at the premises of origin before the contaminated egg packing materials would be returned to nest run farms. The expected number of egg packing materials that were contaminated with leaking eggs prior to cleaning and disinfection and are returned to the nest run farms before HPAI infection is detected is 0.025.r Given that two negative RRT-PCR test results for all the flocks on the premises are obtained before returning egg packing materials, we conclude that the likelihood of contaminated egg packing materials being returned to the nest run farm before HPAI infection is detected is low. Requiring two negative RRT-PCR test results before the return of materials acts as an additional preventive measure for the case where egg packing materials are mistakenly transported to a nest run farm other than the farm of origin.

r From Table 4, the mean number of HPAI virus contaminated eggs flats per day moved from the processing center after two consecutive days of RRT-PCR testing is 1.4. From chapter 8, 1.8 percent of HPAI contaminated eggs would leak on average. As discussed in chapter 9, we had assumed that each contaminated egg would contaminate one egg flat. Therefore, the expected number of HPAI virus contaminated eggs moved per day from the processing center that leak and contaminate an egg flat is 1.4×1.8 percent = 0.0252 eggs.

Number of days of RRT-PCR testing Estimated flats/day

1 2 Mean (Flats/day) 11 1.4

90% interval (Flats/day) 0-44 0-6

Observed maximum in 6000 simulation

iterations 947 126

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10.2.2 Risk that Contaminated Egg Packing Materials Leaving the Off-line Processing Center Result in HPAI Spread to Susceptible Poultry

10.2.2.1 Risk for Plastic Egg Packing Materials Given that egg packing materials are assumed to be returned to the premises of origin as required by the EMC Response plan, the primary movement associated risk is through cross contamination of materials at the processing center. At the processing center, stacks of egg flats may be placed on a conveyor belt where the eggs are automatically removed from the flats to enter the washing process. This creates the possibility of cross-contamination of egg flats via conveyer belts and other processing equipment. For hard, nonporous egg packing materials such as plastic flats, cleaning and disinfection is expected to result in more than 4 log EID50 (10000 factor) inactivation of HPAI virus (see chapter 9). We conclude any virus transferred to hard nonporous materials via cross-contamination at the processing center would be effectively inactivated via washing and sanitization as specified in the Model Cleaning and Disinfection Guidelines. The Model Cleaning and Disinfection Guidelines require cleaned and disinfected egg flats to be palletized on clean pallets and stored in a dry area separate from incoming eggs. In this case, there is little opportunity for plastic egg packing materials to come in direct contact with contaminated processing center surfaces after cleaning and disinfection. We conclude that the risk of hard, nonporous packing materials leaving the processing center and resulting in HPAI spread to susceptible poultry is negligible.

10.2.2.2 Risk for Porous Egg Packing Materials For wooden egg packing materials, assuming that they are returned to the premises of origin, the primary movement associated risk is through cross-contamination of materials at the processing center.

(i) Likelihood and impact of cross-contamination of porous egg packing materials at the off-line processing center prior to cleaning and disinfection. There is a possibility that pallets or nest run cart wheels could be cross-contaminated from processing center floors that were contaminated with HPAI virus present on egg packing materials. The Model Cleaning and Disinfection Guidelines recommend that eggs received from the control area are held in a segregated storage area and processed at the end of the day, before cleaning and disinfection of the loading dock area, receiving storage areas and connecting passages are performed. Assuming that eggs from the control area are only handled at the end of the day followed by cleaning and disinfection of the connecting passages, loading docks and receiving storage areas, it is unlikely that egg packing materials that are not from a control area are cross-contaminated from contaminated processing center floors.

If nest run eggs are received from multiple farms within the control area, it is possible that egg packing materials from uninfected premises are cross-contaminated with HPAI virus from packing materials from infected premises through the processing center floors or

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equipment (i.e. pallet mover). As discussed in chapter 8 and Appendix 12, there would be some reduction in the HPAI viral titer with each successive virus transfer step between surfaces in direct contact with one another. Scenario analysis from Appendix 12 indicated that HPAI viral titer of egg packing materials cross contaminated from the processing center floors may range between 100.0 -102.0 EID50/cm2. As discussed in Appendix 9.3, this HPAI surface viral titer is expected to be effectively inactivated with cleaning and disinfection according to the model guidelines.

(ii) Likelihood and impact of cross-contamination of porous egg packing materials at the off-line processing center after cleaning and disinfection.

There is some risk that wooden egg packing materials could be cross-contaminated with virus from the processing center floor after they are cleaned and disinfected. As mentioned in the previous section, the Model Cleaning and Disinfection Guidelines recommend that egg packing materials from a control area be handled at the end of the day, followed by cleaning and disinfection of the connecting passages, loading docks and receiving storage areas. Furthermore, cleaned and disinfected materials are to be stored in an area separate from that used for incoming eggs. Given these measures, the likelihood that cleaned and disinfected porous egg packing materials are contaminated via the processing center floor is low.

If nest run eggs are received from multiple farms within the control area, the likelihood of egg packing materials from the control area being cross contaminated through the processing center floors or equipment after cleaning and disinfection is low. First, the Model Cleaning and Disinfection Guidelines require cleaned and disinfected materials to be stored in a dry area separate from those used for incoming eggs, thus reducing the likelihood that cleaned and disinfected materials are cross-contaminated from incoming materials. Second, depending on the plant design and specific workflow practices, there is a low likelihood of cross-contamination from the connecting passages (for nest run carts) or pallet moving equipment (for wooden pallets) while moving cleaned and disinfected materials either to their designated storage area or from the storage area to transport vehicle.

In summary, assuming that egg packing materials are returned to the premises of origin as specified in the EMC Response plan, the primary movement associated risk is through cross-contamination of materials at the processing center. We conclude that the risk of cross-contamination of egg packing materials at the processing center prior to cleaning and disinfection resulting in HPAI spread to susceptible poultry is negligible. There is a low likelihood that egg packing materials from the HPAI control area are cross-contaminated through the processing center floors or equipment after cleaning and disinfection. Overall, we conclude that the risk of cleaned and disinfected egg packing materials moved from the off-line processing center resulting in HPAI spread to susceptible poultry is low provided that the preventive measures specified in the EMC Response plan are strictly followed.

10.3 Note on Material Identification for Return of Egg Packing Materials to the Premises of Origin The risk evaluation in this chapter assumes that egg packing materials are returned to the premises of origin. However, in practice there is the possibility that egg packing materials are

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inadvertently moved to premises other than the premises of origin due to errors in material identification. In this section, we briefly comment on the implementation of this measure to return materials to their premises of origin. In addition, we evaluate the overall risk given a scenario where there is a very low but nonzero likelihood that egg packing materials are returned to premises other than the premises of origin. The return of materials to the premises of origin may be implemented by maintaining the identity of shipments or lots of materials. This is often implemented with a labeling system where incoming shipments of nest run eggs and associated materials are tracked by the farm of origin (see Appendix 3 for an example industry description of how nest run shipments are organized and tracked). According to egg industry experts, implementing the segregation and maintenance of the identity of cleaned and disinfected materials by the farm of origin is straightforward and unlikely to result in materials being sent to incorrect premises. The USDA APHIS Layer 1999 data indicate that during routine, non-outbreak operations, 30 percent of the nest run farms return egg pallets to their premises of origin.1 However, quantitative data on the likelihood of egg packing materials being inadvertently moved to a different premises is not available. As mentioned previously, evaluating the likelihood that preventive measures from EMC Response plan are incorrectly implemented is outside of the scope of this assessment. Even when egg packing materials from infected but undetected premises are mistakenly moved to premises other than the premises of origin, the risk of HPAI spread to susceptible poultry would be low provided that other preventive measures (cleaning and disinfection of egg packing materials and ensuring two negative RRT-PCR test results be available before return of the materials, section 10.2.1) are strictly followed. For the scenario where there is a very low but nonzero likelihood that egg packing materials are returned to premises other than the premises of origin, we conclude that the risk of contaminated egg packing materials leaving the off-line processing center resulting in HPAI spread to susceptible poultry is low, provided that other preventive measures from the EMC Response plan are strictly followed.

10.4 Conclusion We conclude that the risk of egg packing materials moved from the off-line processing center resulting in HPAI spread to uninfected, belt-gathered nest run premises is low provided that the following measures from the EMC Response plan are strictly followed: • Egg packing materials are cleaned and disinfected as specified in the Model Cleaning and

Disinfection Guidelines. • Egg packing materials are returned to the premises of origin after at least 24 hours have

elapsed since the eggs were moved from the farm, and the 2 most recent negative RRT- PCR tests for all flocks on the premises are available.

• The loading dock, storage areas and the connecting passages of the off-line processing center are cleaned and disinfected after unloading nest run eggs from the control area, as specified in the Model Cleaning and Disinfection Guidelines.

We note that in routine operations without an HPAI outbreak, it is possible that equipment such as the pallet mover and other tools are transported along with nest run eggs. The risk

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associated with movements of equipment other than the egg packing materials are not addressed in this assessment and may need to be evaluated onsite.

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11. Risk of HPAI Spread to Other Poultry Premises via Vehicle or Driver Leaving the Processing Center

In this chapter, we evaluate the risk that the vehicle or driver transporting egg packing materials from the off-line processing center are contaminated with HPAI virus and result in infection of susceptible poultry.

11.1 Background Information A review of the scientific literature indicates that movements of contaminated equipment, vehicles and personnel between poultry premises is the primary means of spreading HPAI.45,46 Feed and rendering vehicles were associated with the risk of spread of AI virus due to their movement among poultry farms and congregation at common facilities.46 To date, however, there have been no confirmed reports of vehicles transporting nest run eggs as the source of HPAI spread.47-51 In this chapter, we address the movement of vehicles transporting cleaned and disinfected materials from an off-line processing center without poultry on the premises. In this case, unlike vehicles originating from poultry premises, there is no possibility of the vehicle being contaminated from adjacent poultry via people or equipment on the processing plant premises. However, there is a risk pathway for cross-contamination of vehicles or personnel, from other vehicles, people or packing materials originating from HPAI infected nest run farms. The EMC Response plan requires the cleaning and disinfection of the vehicle and processing center shipping docks and specifies biosecurity procedures for drivers. We consider these Model Cleaning and Disinfection Guidelines and biosecurity measures in our risk evaluation.

Risk of HPAI Spread to Other Poultry Premises via Vehicle or Driver

Leaving the Processing Center • Risk Factors: Cross-contamination of transport vehicle via shipping docks, inadequate cleaning and disinfection, and failure of biosecurity practices for personnel. • Current Preventive Measures: Industry good manufacturing practices (GMPs). • Additional Preventive Measures (to be implemented by industry during an outbreak; see Appendix 14 for suggested protocols): Biosecurity and cleaning and disinfection procedures for the driver, truck exterior and interior; Product specific biosecurity requirements as described in the EMC Response plan. • Overall Risk: low, provided the above additional preventive measures are strictly followed.

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11.2 Preventive Measures

11.2.1 Current Preventive Measures Industry good manufacturing practices followed at egg processing plants typically contain provisions for preventing contamination of clean trucks or materials that are leaving the processing center and destined for poultry premises. The industry GMPs are variable among processing plants, however, and are not evaluated in this risk assessment.

11.2.2 Preventive Measures during an Outbreak In the event of an HPAI outbreak, various movement control measures will be implemented by local, State and/or Federal authorities as part of the disease control effort.45,52-54 Vehicle cleaning and disinfection procedures are included in these measures. APHIS and the nest run egg industry recognize the potential risk from vehicles or conveyances and the importance of reducing this risk. The EMC Response plan thus initiates regulation of the movement of vehicles transporting eggs and associated materials during an outbreak (Appendix 1).55

The EMC Response plan includes cleaning and disinfection of all vehicles transporting nest run eggs that move into, within or outside of a control area.s The cargo interior and exterior of the movement vehicle must be cleaned before a permit is issued. In addition, tires and wheel wells of vehicles moving nest run eggs must be cleaned and disinfected before leaving premises within a control area. The driver will not be allowed outside of the cab or the cab interior must also be cleaned and disinfected. Cleaning and disinfection requires the use of an EPA approved disinfectant42 with efficacy against AI virus following a standard protocol that will require vehicle interior and exterior cleaning and disinfection.t The EMC Response plan does not require vehicles to be cleaned and disinfected on the premises, but it does require that cleaning and disinfection be done before a movement permit is issued. The Model Cleaning and Disinfection Guidelines (Appendix 2) specify biosecurity and cleaning and disinfection protocols for loading docks receiving shell eggs from control areas. These guidelines recommend processing eggs from the control area as the “last eggs” handled on the day. In addition the guidelines specify cleaning and disinfection procedures for the loading dock area, receiving storage areas and connecting passages after receiving a shipment of eggs from a control area. Additional protocols for cleaning and disinfection exist and new ones may need to be developed depending on the circumstances. For example, vehicle cleaning and disinfection guidelines are given in the November 2005 Draft National Animal Health Emergency

s Vehicles carrying eggs into a control area will be subject to cleaning and disinfection when they arrive at their delivery points. t http://www.epa.gov/pesticides/factsheets/avian_flu_products.htm. Note that although there are no antimicrobial products registered specifically against the H5N1 subtype of avian influenza A viruses, EPA believes based on available scientific information that the currently registered avian influenza A products, when applied in strict accordance with the label directions, will be effective against the H5N1 strain.

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Management System (NAHEMS) Cleaning and Disinfection Operational Guidelines from the USDA,53 and general biosecurity guidelines are given in the April 2005 Draft National Animal Health Emergency Management System (NAHEMS) Biosecurity Operational Guidelines from the USDA.54


The potential risks associated with vehicles and personnel leaving the processing center are:

a) Risk that susceptible poultry are exposed to HPAI virus via the vehicle transporting egg packing materials from the processing center.

b) Risk that susceptible poultry are exposed to HPAI virus via the vehicle driver transporting egg packing materials from the processing center.

11.3.1 Risk that Susceptible Poultry are Exposed to HPAI Virus via Vehicle Transporting Egg Packing Materials from the Processing Center

11.3.1.1 Risk that Susceptible Poultry are Exposed to HPAI Virus via Interior of the Vehicle Transporting Egg Packing Materials from the Processing Center After delivering the nest run eggs, the trailer interior is cleaned and disinfected with an EPA registered disinfectant against avian influenza viruses. Although the vehicle is expected to be decontaminated at this point, there are post-cleaning and disinfection contamination risk pathways that must be evaluated. In brief, a shared shipping dock for incoming nest run eggs and outgoing cleaned and disinfected materials presents the possibility that a cleaned and disinfected vehicle is cross-contaminated with HPAI virus from the shipping dock via personnel or equipment. We evaluated this risk in three parts as follows:

(i) The HPAI viral titer on the shipping dock and processing center floors that are contaminated while receiving nest run eggs from HPAI infected but undetected premises. The degree of contamination of shipping docks and processing center floors depends on the HPAI viral titer on egg packing materials and on the trailer floor of the vehicle coming from an infected but undetected premises, and the efficiency of viral transfer from egg packing materials or floors to personnel shoes. In chapter 8 and Appendix 12, we developed a model to estimate the degree of HPAI viral contamination on various surfaces via pathways that involve successive transfers of virus between contact surfaces. Experimental data on transfer rates of various human viruses between contact surfaces and the amount of soil adhering to shoes were used for this model (see Appendix 12 for details). In the baseline scenario of this model, using the most likely values for each parameter, the viral titer on the shipping dock or processing center floors contaminated through this pathway is less than 1 EID50/cm2. This viral titer is unlikely to pose a risk of HPAI spread to susceptible poultry. However, in the conservative scenario, the viral titer on the loading dock or processing center floors contaminated through this pathway was estimated to be as high as 102.5 EID50/cm2.

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(ii) Impact of cleaning and disinfecting shipping docks, receiving storage areas and connecting passages. The Model Cleaning and Disinfection Guidelines require nest run eggs from an HPAI control area to be received at the end of the day before cleaning and disinfection of the facility. Furthermore, these guidelines require shipping docks, receiving storage areas and connecting passages at the processing center to be cleaned and disinfected after receiving eggs from a control area. As discussed in chapter 9, cleaning and disinfection of hard, nonporous surfaces with an EPA registered AI virucidal disinfectant used according to the manufacturer’s label directions is expected to result in more than a 4 log EID50 (10,000 factor) inactivation of HPAI virus. We conclude that any HPAI virus transferred to processing center floors from egg packing materials originating from an HPAI infected but undetected premises would be effectively inactivated after cleaning and disinfection according to the Model Cleaning and Disinfection Guidelines.

(iii) The HPAI viral titer from personnel shoes or loading equipment transferred to the trailer interior of the vehicle transporting cleaned and disinfected materials to nest run farms. The Model Cleaning and Disinfection Guidelines require egg packing materials from a control area to be handled at the end of the day before cleaning and disinfection of the shipping docks. Given that egg packing materials that are not from an HPAI control area are loaded through shipping docks and connecting passages that have been cleaned and disinfected after being used for egg packing materials from a control area, we conclude that the risk of susceptible poultry being exposed to HPAI virus from the interior of the vehicle transporting egg packing materials to nest run farms outside the control area is negligible. The shipments of nest run eggs from an HPAI control area may not be separated in time. A potential pathway for the contamination of the trailer interior of a vehicle transporting egg packing materials in this case, involves the following sequence of events:

• A processing center shipping dock is contaminated while unloading egg packing materials from an HPAI infected but undetected flock.

• Shoes of the shipping dock personnel become contaminated through contact with the contaminated shipping dock or the trailer floor of a vehicle coming from an HPAI infected but undetected flock.

• The trailer interior of the vehicle destined for an uninfected premises in the control area is contaminated from the shoes of personnel loading cleaned and disinfected egg packing materials.

The degree of contamination of the trailer interior through the above pathway is likely low given the multiple viral transfer steps involved in the pathway. As discussed previously, there would be a reduction in surface viral titer with each viral transfer step since only a fraction of the virus present on a donor surface is transferred to the recipient surface through direct contact. In the baseline scenario of the virus transfer model presented in Appendix 12, the HPAI viral titer on shipping docks or the trailer interior of the incoming vehicle were estimated to be less than 1 EID50/cm2. In this case, the HPAI viral titer of the shoes of the shipping dock personnel and interior of the outbound vehicle transporting egg packing materials would be even lower and unlikely to cause HPAI spread to susceptible poultry. In

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the conservative scenario, the HPAI viral titer on the shipping dock or the trailer interior of an incoming vehicle was estimated to be 102.48 EID50/cm2. In this case, conservatively assuming that 40 percent of the virus present on a contact surface is transferred to a virus-free contact surface (Appendix 12), the HPAI viral titer on personnel shoes contaminated from either the shipping dock or the trailer interior of the incoming vehicle would be 102.08 EID50/cm2. The viral titer on the trailer interior of the outgoing vehicle subsequently contaminated from personnel’s shoes during loading would then be 50 EID50/cm2. This viral titer represents a low risk of HPAI spread to susceptible poultry.

In summary, we used two different scenarios to evaluate the HPAI viral titer on the trailer interior of the vehicle transporting egg packing materials from the processing center. Cross-contamination of the vehicle interior could be from the shipping docks or connecting passages, transferred via personnel shoes or equipment. The estimated viral titer on the trailer interior was inconsequential for the risk of HPAI spread under the baseline scenario. In the conservative scenario, the viral titer on the trailer interior was estimated to be 50 EID50/cm2. Overall, we conclude that the risk that susceptible poultry are exposed to HPAI virus from the interior of the vehicle moving cleaned and disinfected packing materials back to the premises of origin is low.

11.3.1.2 Risk of Cleaning and Disinfection not Inactivating HPAI Virus on the Vehicle Exterior The EMC Response plan contains provisions for cleaning and disinfection of vehicles during an outbreak. These plans are similar to ones developed to control the Exotic Newcastle Disease (END) outbreak in California and were found to be effective in that situation. The movement control plan requires cleaning and disinfection of the cargo interior, exterior, tires and wheel wells of the transportation vehicles. Similarly, other relevant guidelines such as the NAHEMS guidelines address the cleaning and disinfection of vehicles in detail.53 These cleaning and disinfection procedures would effectively inactivate HPAI virus on the vehicle exterior given the sensitivity of HPAI virus to most detergents and disinfectants (see chapter 9).

The exterior of trucks delivering nest run eggs to the off-line processing center would be cleaned and disinfected prior to arrival according to the protocols mentioned above. Hence there is little opportunity for the truck exterior to become contaminated with HPAI virus at the off-line processing center. We conclude that the risk of HPAI virus remaining on the exterior of a vehicle that has been cleaned and disinfected as specified in the EMC Response plan is negligible.

11.3.2 Risk of the Driver of the Vehicle Transporting Cleaned and Disinfected Packing Materials being Contaminated with HPAI Virus The Model Cleaning and Disinfection Guidelines described in EMC Response plan require all truck drivers to wear coveralls and boots while outside the cab and remove them immediately before reentering the cab. The EMC Response plan also requires the cab interior to be cleaned and disinfected if the driver steps out of the cab. Given these personnel protective equipment (PPE) measures, there is limited opportunity for the driver’s clothes or shoes to become contaminated from the processing center shipping docks or connecting

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passages. Furthermore, the degree of contamination of shipping docks or storage areas for cleaned and disinfected materials is low as discussed in section 11.3.1.

There may be a possibility that the vehicle driver helps unload eggs coming in from other nest run farms at the processing center. From Appendix 12, the HPAI viral titer on the trailer interior of the vehicle transporting nest run eggs is expected to be low. The use of protective coveralls and boots at the nest run farm will further reduce risk that the vehicle driver transmits HPAI virus to uninfected nest run premises. The incident command and movement permitting systems provide for review of and compliance with these procedures as well as industry biosecurity measures already in practice. The EMC Response plan also requires the cab interior to be cleaned and disinfected if the driver steps out of the cab. We conclude that the risk that the driver transmits HPAI virus to nest run premises is low if the relevant PPE and biosecurity guidelines are strictly followed.

11.4 Conclusion In this chapter, we evaluated the risk that the vehicle or driver transporting egg packing materials from an off-line processing center are contaminated with HPAI virus and result in infection of susceptible poultry. The key preventive measures from the EMC Response plan that were considered for the risk evaluations are as follows:

• Cleaning and disinfection of the vehicle interior and exterior as specified in the Model Cleaning and Disinfection Guidelines.

• PPE and biosecurity measures for the vehicle driver as specified in the Model Cleaning and Disinfection Guidelines

• Cleaning and disinfection of the shipping docks, connecting passages and receiving storage areas of the off-line processing center after receiving nest run eggs from an HPAI control area.

Provided that the above measures are strictly followed, we conclude: • The risk of susceptible poultry being infected with HPAI virus from the vehicle

transporting egg packing materials from the off-line processing center is low (Appendix 14).

• The risk of susceptible poultry being infected with HPAI virus via the vehicle driver transporting egg packing materials from the processing center is low (Appendix 14).

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12. Risk Evaluation for Nest Run Premises that Hand Gather Eggs This portion of the risk assessment addresses the risk of HPAI spread to susceptible poultry associated with the movement of nest run eggs from an infected but undetected hand gathering premises to an off-line processing center. The movement of cleaned and disinfected egg packing materials from an off-line processing center to nest run premises that hand gather eggs is also addressed in this section.

12.1 Background Information The majority of nest run farms in the United States use an automated belt gathering system for collecting eggs, and the current industry trend is toward this method. Although our risk evaluations thus far have focused on evaluating nest run farms that employ automated belt gathering systems, a significant fraction of nest run farms may still practice hand gathering. The USDA APHIS Layer 1999 survey found that about 28.6 percent of all farm sites practiced hand gathering.1 Hand gathering of eggs is more popular in the western regions of the United States where labor costs are lower. There are important differences between hand gathered operations and belt gathered operations that must be considered in this risk assessment. For instance, hand gathered systems may have higher personnel traffic between the henhouse and the egg packing or storage areas. Egg packing materials such as egg flats and carts are nearly always brought into the henhouse, exposing them to contamination with dust and aerosols comprised of respiratory secretions and manure. In this chapter we evaluate the risks for HPAI spread and any preventive measures that pertain specifically to hand gathering nest run farms.

Risk Evaluation for Nest Run Premises that Hand Gather Eggs • Risk Factors: Frequent personnel traffic between the henhouse and the egg packing or storage areas; bringing egg packing materials into the henhouse. Cross-contamination of cleaned and disinfected materials at the off-line processing center. • Current Preventive Measures: Industry good manufacturing practices (GMPs). • Additional Preventive Measures (to be implemented by industry in conjunction with APHIS during an outbreak): Cleaning and disinfection procedures for the truck exterior and interior; product specific biosecurity requirements as described in EMC Response plan; using only new, disposable egg flats for transport of hand gathered nest run eggs to an off-line processing center.

• Overall Risk: low provided the above preventive measures are strictly followed.

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We evaluated these risk pathways in two parts:

a) Risk that movement of nest run eggs from an infected but undetected premises that hand gathers eggs results in HPAI spread to susceptible poultry.

b) Risk that movement of cleaned and disinfected egg packing materials to a hand gathering premises results in HPAI spread to susceptible poultry.

12.2.1 Risk that Movement of Nest Run Eggs from an Infected but Undetected Premises that Hand Gathers Eggs Results in HPAI Spread to Susceptible Poultry The potential pathways for this risk to occur are as follows:

1. Egg packing materials from an infected but undetected nest run farm contaminate floors or equipment at the processing center, which in turn cross-contaminate materials destined for other premises.

2. Egg packing materials from an infected but undetected nest run farm contaminate shipping docks or processing center floors, which in turn cross-contaminate vehicles destined for other premises.

The key risk events in the above pathways and the specific modes of virus transfer are the same regardless of whether eggs are hand gathered or collected on conveyer belts. However, the likelihood and degree of contamination of egg packing materials may be higher for hand gathered eggs due to the following reasons:

1. Higher frequency of movements between the egg storage area and the henhouse. 2. Egg flats and carts are taken into the henhouse in hand gathered operations.

Hand gathered operations may use carts to accumulate eggs as they are collected in the henhouse. The relatively frequent movement of personnel and equipment (carts and egg flats) to and from the henhouse in hand gathered operations results in a greater likelihood of contamination of the egg storage and packing areas. Consequently, the likelihood that egg packing materials placed on egg storage or packing area floors become contaminated is also higher for hand gathering nest run farms. In addition, egg flats and carts that are brought into the henhouse have a greater likelihood of contamination with manure, dust, and respiratory aerosols. Apart from the above considerations, the rest of the risk evaluation for these pathways is similar to that for belt gathered operations as described in chapters 10 and 11. However, the likelihood and degree of contamination of processing center floors or equipment is higher when handling egg packing materials from a hand gathered nest run premises. In this case, the conservative scenario of Appendix 12 may be more appropriate for estimating the viral titer on the processing center floors and egg packing materials cross-contaminated from the floors. In this scenario, the estimated viral titer on the processing center floors was 102.5

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EID50/cm2 and the estimated viral titer on egg packing materials contaminated from the floors was 102 EID50/cm2. As discussed in chapter 10, the risk of cross-contamination of egg packing materials at the processing center prior to cleaning and disinfection resulting in HPAI spread to susceptible poultry is negligible. The likelihood of cross-contamination of egg packing materials after cleaning and disinfection is low under the following conditions: 1) cleaned and disinfected materials are segregated in a storage area separate from incoming eggs; 2) shipping docks, receiving storage areas and connecting passages are cleaned and disinfected after handling nest run eggs from an HPAI control area. We conclude that the risk that movement of nest run eggs from infected but undetected hand gathering premises results in HPAI spread to susceptible poultry is low. We note that the risk associated with the movement of nest run eggs is relatively higher for hand-gathering farms compared to belt-gathering farms although the overall risk rating is low in both these cases.

12.2.2 Risk that Movement of Cleaned and Disinfected Egg Packing Materials to a Hand Gathering Premises Results in HPAI Spread to Susceptible Poultry The EMC Response plan requires that only new paper or disposable fiber flats be used for hand gathering eggs. The possibility of HPAI spread due to the movement of contaminated egg flats to nest run farms that hand gather eggs is thus eliminated. However, supporting egg packing materials such as pallets or carts may be returned to hand gathering nest run farms after cleaning and disinfection. In this case, cross-contaminated pallets, nest run carts, floors and equipment at the processing facility together create plausible risk pathways for HPAI virus spread that need to be evaluated. We have determined that the likelihood and degree of cross-contamination of these egg packing materials are similar to that incurred with belt gathered eggs. However, hand gathering premises present a greater likelihood of exposure of HPAI virus to susceptible poultry via contaminated egg packing materials when the packing materials are brought into the henhouse. We conclude that the risk that movement of cleaned and disinfected egg packing materials to a hand gathering premises results in HPAI spread to susceptible poultry is low, provided that reusable cleaned and disinfected egg packing materials returned from the processing center are not brought into the henhouse.

12.3 Conclusion

For nest run farms that hand gather eggs and have implemented the EMC Response plan, we conclude the following: • The likelihood that egg packing materials moved from an infected but undetected

premises are contaminated with HPAI virus is higher for hand gathering premises as compared to premises that belt gather eggs.

• The risk of HPAI infection in susceptible poultry due to the movement of hand gathered

nest run eggs from an infected but undetected premises is low (Appendix 14) provided that:

o New or disposable egg flats are used for moving hand gathered nest run eggs to

the off-line processing center.

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o Reusable egg packing materials are cleaned and disinfected as specified in the Model Cleaning and Disinfection Guidelines.

o Reusable egg packing materials are returned to the premises of origin after at least 24 hours have elapsed since the eggs were moved from the farm, and the 2 most recent negative RRT-PCR tests for all flocks on the premises are available.

o The shipping dock, storage areas and connecting passages of the off-line processing center are cleaned and disinfected after unloading nest run eggs from the control area.

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13. Overall Conclusions

The objective of this assessment was to estimate the risk that the movement of nest run eggs into, within, and outside of a control area during a highly pathogenic avian influenza outbreak in the poultry industry in the United States will result in HPAI infection of other poultry premises. With respect to the major component risks that were analyzed, this document concludes the following:

a) For an HPAI infected but undetected flock of 100,000 layers for which the active surveillance protocol described in the Egg Movement Control Response plan is implemented, there is a 95 percent chance that less than 2 egg flats per day are contaminated with HPAI virus from the contents of leaking eggs and moved before infection is detected.

b) The cleaning and disinfection of egg packing materials as specified in the Egg

Movement Control Response plan would:

• Effectively inactivate HPAI virus on contaminated hard nonporous egg packing materials.

• Effectively inactivate HPAI virus on most of the contaminated hard porous egg packing materials. A small fraction of porous egg packing materials may have a residual surface viral titer greater than 4 EID50/cm2 after cleaning and disinfection.

It is concluded that the overall risk that the movement of nest run eggs into, within, and outside of a control area during an HPAI outbreak will result in HPAI infection of other poultry premises is low, provided that the preventive measures from the Egg Movement Control Response plan and associated Model Cleaning and Disinfection Guidelines listed below are strictly followed: • The RRT-PCR testing based active surveillance protocol is implemented for all flocks

on the premises. • Packing materials used to transport nest run eggs are cleaned and disinfected as

specified in the Model Cleaning and Disinfection Guidelines or disposed of at the processing center.

• Egg packing materials are returned to the premises of origin after at least 24 hours have elapsed since the eggs were moved from the farm, and the 2 most recent negative RRT-PCR tests for all flocks on the premises are available.

• The interior and exterior of the vehicle transporting nest run eggs is cleaned and disinfected as specified in the Model Cleaning and Disinfection Guidelines.

• The vehicle driver follows the PPE and biosecurity measures specified in the Model Cleaning and Disinfection Guidelines.

• The shipping dock, storage areas and connecting passages of the off-line processing center are cleaned and disinfected after receiving nest run eggs from the control area, as specified in the Model Cleaning and Disinfection Guidelines.

• Nest run eggs from a control area are processed at the end of the day. • Only new or disposable flats are used to move hand-gathered nest run eggs.

However, it should be remembered that:

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a) This assessment is based on current (April 2010) information and will need to be reviewed and revised as circumstances warrant.

b) The assessment aids, but does not replace, the judgment of on-scene officials.

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Acknowledgements We sincerely thank all those who contributed to the planning, writing and reviewing of this risk assessment. In addition to all members within the Egg Products Industry working group, the University of Minnesota’s Center for Animal Health and Food Safety, and the United States Department of Agriculture (USDA), we acknowledge and appreciate the generous assistance of the following people: Dr. Eric Benson, Dr. Tajah Blackburn, Dr Dean Cliver, Dr. Eric Gingerich, Dr. Deana Jones, Ms. Julie Mayer, Dr. Amber McCoig, Dr. Sayed Sattar, Dr. Erica Spackman, Dr. Susan Springthorpe and Dr. David Swayne.

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Appendix 1. Selected Sections of Egg Movement Control Response Plan from the Draft USDA-APHIS-VS Secure Egg Supply Plan The following are selected sections of the EMC Response plan from the draft USDA-APHIS-VS Secure egg supply plan. The numbering in this appendix relates directly to the sections of the existing version of the draft USDA-APHIS-VS Secure Egg Supply plan. Efforts to control the spread of and eradicate HPAI may compete with the egg industry’s real time need to move eggs and associated egg products. These competing needs can be resolved, in part, by elevating awareness, establishing or reinforcing communication links between regulators and industry, identifying resources, identifying existing and elevated biosecurity practices and developing plans in advance of an outbreak. An Egg Sector Working Group (comprised of egg industry members and the United Egg Producers), the University of Minnesota CAHFS, the Iowa State University CFSPH, APHIS, CEAH staff, and APHIS, NCAHEM staff have participated in a private-public-academic partnership to develop effective science-based solutions for the continuity of business in a Control Area during a HPAI outbreak. The outcome of this partnership is a set of specific science-based tools which decision makers (e.g., Incident Commanders) can utilize in order to evaluate the producer’s biosecurity program, to understand the product risk and to shorten the time needed to allow for permitted movement of low risk egg products or poultry.

• The Egg Movement Control Response Plan: Commercial Layer Industry Operations Protocol for movement of eggs, egg products and chicks. The EMC Response plan identifies specific surveillance, biosecurity, cleaning and disinfecting practices for moving different types of eggs, egg products and day-old chicks within, out of and into a Control Area. Example Model Cleaning and Disinfection Guidelines are included in Attachment B of the following document. It also offers draft guidance for movement of eggs, egg products and day-old chicks. (See Table 2-1)

• Evidence of flock health by daily surveillance for normal egg production, feed and

water consumption, mortality and clinical signs of HPAI along with evidence of daily negative RRT-PCR for HPAI.

• USDA-APHIS VS CEAH assessments of the risk of HPAI transmission associated

with the movement of each type of egg, egg product and day-old chicks have been completed.

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Figure 3-1. Egg Movement Flowchart

YES

NO

YES YES

YES

YESNO

NO

YES

YES

NO

YES

NO

Infected Premises

(Meets 1.1

definition )

Move to Monitored

(If meets Definition

Section 5.1)

Contact

Premises

Contact with

Infected Flock ?

(Meets 2.1

definition )

Move to Infected

Premise

Quarantine

(Section 3.2)

PCR Test

Positive ?

Confirmation ?

Complete EPI

Investigation and

PCR Testing

M eans partial EPI is done

PCR Negative &

Mortality Normal

Quarantine &

Depop

(Section 1.2)

M eans com plete EPI is

done and PCR Neg .

Quarantine

(Section 4.2)

“Free” Premises

(Section 6.2)

Suspect

Premises Birds

show clinical

signs of HPAI ?

(Meets 3.1

definition )

At Risk Premises Birds

show no sign of disease

but complete EPI not

done OR No PCR Neg .

Tests

(Meets 4.1 Definition )

Move to Monitored

(If meets definition

Section 5.1)

Quarantine

(Section 2.2)

Move to Infected ,

Contact or

Monitored status

Decision point

NO

EPI

Investigation

shows low risk

& PCR Tests

Negative ?

Premise

Outside of

Infected &

Buffer Zone

Areas?

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4.1 Response Zones and Premise Designations for the EMC Response plan

Please refer to the NAHEMS Guidelines: Response Strategies: Highly Contagious Foreign Animal Diseases for a complete description of response zones and premises. Figure 4.1 displays all the zones and premises in an outbreak response. Figure 4.1 Example Zones and Premises in an Outbreak Response (Left: Circle; Right:

Irregular)

4.1.1 Flocks That Are Determined to Be Infected Premises By Epidemiological Investigation and/or Diagnostic Testing

Figure 4.2 Example Infected Premises Diagram (Left: Circle; Right: Irregular)

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Definition of Infected Premises Infected Premises are premises where HPAI is presumed or confirmed to exist based on laboratory results and compatible clinical signs. (See Figure 4.2) All presumed positive premises and confirmed positive premises are classified as Infected Premises. In addition, all other premises that meet the current case definition for HPAI are classified as Infected Premises.

Disposition of Infected Premises Infected Premises are quarantined immediately, and all susceptible birds and other susceptible livestock will be depopulated and disposed of following proper biosecure procedures. No movement of susceptible species or their products (e.g., shell eggs, hatching eggs, day old chicks, broken egg shells, non-pasteurized liquid egg product, pasteurized egg products) will be allowed off the Infected Premises, except for disposal and must be moved under permit.

4.1.2 Flocks That Are Determined to Be Contact Premises By Epidemiological Investigation

Figure 4.3 Example Contact Premises Diagram (Left: Circle; Right: Irregular)

Definition of Contact Premises

Contact Premises are premises with birds or other susceptible animals that have been exposed directly or indirectly to birds and other animals, conveyances, or products, fomites, materials, people or aerosol from an Infected Premises. (see Figure 4.3) The specific exposure factors to be considered must be appropriate to the epidemiology of HPAI. The commercial layer industry HPAI Contact Premises include the following direct or indirect contact sources:

a. Premises with susceptible birds exposed to poultry manure from an infected flock (virus in manure).

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b. Premises with susceptible birds exposed to dead poultry from an infected flock (virus in carcasses, etc).

c. Premises with susceptible birds exposed to live poultry from an infected flock (virus in bird & secretions & excretions).

d. Premises with susceptible birds exposed to eggs or egg handling materials from an infected flock (HPAI virus in and on egg).

e. Premises with susceptible birds with unprotected exposure to equipment that have been in contact with infected birds, manure, carcasses, or eggs. Unprotected means inadequate sanitation procedures for those items/people that come into contact with an infected flock.

f. Premises with susceptible birds with unprotected exposure to people who have been in contact with infected birds, manure, carcasses, or eggs.

g. Premises involved in depopulation of infected flocks. Disposition of Contact Premises

Contact Premises will be quarantined and subject to strict biosecurity measures, daily monitoring of mortality in each house, and intensive surveillance for HPAI viruses in each house by RRT-PCR testing (See ‘Determination of non-infected layer industry flocks in the Control Area’) until the Incident Commander is convinced that no HPAI is present on the premises.

h. Following complete epidemiological investigation, biosecurity assessments, and negative diagnostic testing for HPAI, Contact Premises can be re-designated as Monitored Premises.

i. Contact Premises with 75,000 hens or more will not be depopulated until a diagnosis for HPAI has been confirmed by case definition or diagnostic testing.

j. Contact Premises that are determined to be HPAI infected by case definition or diagnostic testing will be depopulated immediately.

k. Appropriate risk assessments will direct movement from Contact Premises by permit. Based on USDA APHIS risk assessments, incident command may immediately permit movement of negligible risk products.

4.1.3 Flocks That Are Determined to Be Suspect Premises By Epidemiological Investigation

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Figure 4.4 Example Suspect Premises Diagram (Left: Circle; Right: Irregular)

Definition of Suspect Premises

Suspect Premises are premises where birds or other susceptible livestock are under epidemiological investigation for a report of clinical signs compatible with HPAI, but the case definition for HPAI has not been met, and HPAI has not been detected or confirmed by diagnostic testing. (see Figure 4.4) Disposition of Suspect Premises

Suspect Premises will be quarantined and subject to strict biosecurity measures, daily monitoring of mortality in each house, and surveillance for HPAI viruses in each house by RRT-PCR testing (See ‘Determination of non-infected layer industry flocks in the Control Area’), until the conditions are met to re-designate the Suspect Premises as an Infected Premises, or a Monitored Premises.

l. Suspect Premises must have complete epidemiological investigation, biosecurity assessments, and test negative for HPAI before being re-designated a Monitored Premises (see Section 4.1.5).

m. Suspect Premises with 75,000 hens or more will not be depopulated until a diagnosis of HPAI has been confirmed by case definition or diagnostic testing.

n. Suspect Premises that are determined to be HPAI infected by case definition or diagnostic testing will be depopulated immediately.

o. Appropriate risk assessments will direct movement from Suspect Premises by permit.

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4.1.4 Flocks That Are Designated as At-Risk Premises Prior to Epidemiological Investigation

Figure 4.5 Example At-Risk Premises Diagram (Left: Circle; Right: Irregular)

Definition of At-Risk Premises

At-Risk Premises are those premises in the Control Area (Infected Zone or Buffer Zone) that have susceptible animals, but none of those susceptible animals have clinical signs compatible with HPAI. (see Figure 4.5) At-Risk Premises have not been subject to epidemiological investigation, biosecurity assessments, or diagnostic testing for HPAI to warrant a re-designation to Contact Premises or Monitored Premises. Disposition of At-Risk Premises

At-Risk Premises are quarantined by virtue of the fact that they are located within the Control Area and animals susceptible to HPAI and non-negligible risk products for HPAI cannot be moved out of the Control Area without a permit from the Incident Commander. After complete epidemiological investigation, biosecurity assessments, and diagnostic testing for HPAI, At-Risk Premises can be re-designated to Contact Premises or Monitored or Infected Premises.

p. Appropriate risk assessments will direct movement from At-Risk Premises by permit. Based on USDA APHIS risk assessments, incident command may immediately permit movement of negligible risk products.

4.1.5 Flocks That Are Determined to Be Monitored Premises By Epidemiological Investigation

Figure 4.6 Example Monitored Premises Diagram (Left: Circle; Right: Irregular)

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Definition of “Monitored” Premises

Monitored Premises are in close proximity to an infected flock, and are located in the Infected Zone or Buffer Zone, which comprise the Control Area. (see Figure 4.6) Monitored Premises can objectively demonstrate that they are not to be designated as Infected Premises, Contact Premises, Suspect Premises, or At-Risk Premises, following complete epidemiological investigation, biosecurity risk assessments, and diagnostic testing for HPAI. Monitored Premises objectively demonstrate:

• Monitored Premises objectively demonstrate that they do not meet the definitions for Infected Premises, Contact Premises, Suspect Premises, or At-Risk Premises by complete epidemiological investigation and questionnaire.

• Monitored Premises objectively demonstrate that systematic biosecurity measures and precautions have been taken to protect the premises against HPAI.

• Monitored Premises objectively demonstrate flock health parameters by routinely sharing them with Incident Command.

• Monitored Premises objectively demonstrate diagnostic testing negative for HPAI.

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Disposition of Monitored Premises

q. Premises located within the Control Area must only be designated Monitored Premises by the Incident Commander or their designee.

r. The designation of Monitored Premises during an actual incident by the Incident Commander or their designee will be facilitated and accelerated by biosecurity risk assessments conducted prior to the incident, by rapid epidemiological investigation and epidemiological questionnaire at the time of the incident, strategic placement of diagnostic sampling equipment prior to the incident, and tactical execution of diagnostic sample testing at the start of the incident.

s. Monitored Premises, depending upon their location, the actual incident circumstances, and epidemiological considerations of the actual outbreak, will be granted permits to move Liquid Egg Product, Further Processed Egg Products, Inedible Egg, Table Eggs, Nest Run Eggs, and Broken Egg Shells, Egg-Type Hatching Eggs, and Day-Old chicks Within, Out of, and Into a Defined Control Area at the discretion of the incident commander or their designee. Appropriate risk assessments will direct movement from Monitored Premises by permit with no delay for negligible risk products.

4.1.6 Flocks That Are Determined to Be Free Premises By Epidemiological Investigation

Figure 4.7 Example Free Premises Diagram (Left: Circle; Right: Irregular)

Definition of Free Premises

Free Premises consist of flocks which are outside of the Control Area (Infected and Buffer Zones) and are not considered to be Contact, Suspect, At-risk or Monitored Premises. (see Figure 4.7)

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Disposition of Free Premises

No special movement requirements will be imposed on Free Premises since they are not considered to be involved in the outbreak. Premises in a free surveillance zone may be tested as necessary.

Figure 4.8 Premises Designations

4.2 Determination of Non-Infected Layer Industry Flocks in the Control Area

4.2.1 The potential presence of infection will be monitored by requiring chickens from flocks that are not exhibiting signs of the disease and that show no unexpected increase in mortality from each house on the farm to be tested each day and found to be negative by the RRT-PCR or other suitable procedure as determined by the Incident Command.

t. A minimum of five dead chickens from daily mortality and/or from euthanized sick birds from each house (flock) will be placed in a leak-proof container (e.g., heavy duty plastic garbage bag) each morning. Each container will be labeled with the farm of origin, house of origin, number of birds found dead in the house that day, and the premises identification. After samples have been taken, farm personnel will dispose of the carcasses in accordance with a biosecure protocol.

u. A state or federal regulatory official or an individual authorized by the Incident Command (IC) will take an “oropharyngeal” swab from each chicken. Five oropharyngeal swabs will be pooled in a tube containing brain-heart infusion (BHI) broth. Sample pooling will be done on a per house basis. One BHI tube containing oropharyngeal samples (5 oropharyngeal swabs/BHI tube) will be submitted as directed by the Incident Command to an authorized State Veterinary Diagnostic Laboratory (VDL). These samples must be submitted on the day of sample collection by a state or federal regulatory official or an individual authorized by the Incident Command. The State VDL and the IC will establish the time of day by which samples must be submitted to an authorized VDL (example, by 12:30 pm). VDL personnel will perform RRT-PCR testing on these samples immediately upon receipt and electronically send test results to the IC by the end of each day. The IC will report the test result information to the premises as soon as it is available.

v. Daily surveillance consists of RRT-PCR tests from 5 dead chickens per 50 dead chickens from each house on the premises (defined as 1 pool). To move eggs and egg products into market channels for human consumption, RRT-PCR tests on two consecutive pools from each house on the premises must be negative. Two negative RRT-PCR pools on the first day of testing or two negative RRT-PCR pools on consecutive days are necessary. On subsequent days, one pool from each house on a premises must test negative for avian influenza by the RRT-PCR test. This is sufficient to allow eggs stored for 48 hours from the day of production to be moved to market.

w. If the RRT-PCR test on the dead bird pool is not negative, nothing moves until additional sampling results in a negative diagnosis.

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If the daily mortality spikes (over 3 times the 7 day average daily mortality) nothing moves until additional sampling results in a negative diagnosis.

4.3 Movement of Egg Industry Products

This movement will be allowed by permit as appropriate for those flocks inside the Control Area testing negative as follows, including any unsold inventories on hand. Products of negligible risk will be quickly allowed to move using permits and without the need for complete epidemiological investigation (see Table 1.1). To date, the following proactive risk assessments are in process but have not been completed (see Table 1.1): hatching eggs, day-old chicks, and egg shells and inedible. The following sections will discuss truck and biosecurity for commodity specific products. More detailed information can be found in Attachment B.

4.3.1 USDA FSIS Inspected Pasteurized Egg Products, or Precooked Egg Products

USDA FSIS Inspected Pasteurized Egg Products, or Precooked Egg Products produced by plants within a Control Area are considered to be of negligible risk based on USDA-APHIS CEAH risk assessment and may move within or out of the Control Area by a Permit (accompanied by documentation of origin of the products).

Truck and Driver Biosecurity*: • The cargo interior and exterior of the transport vehicle must be cleaned

and disinfected. • The driver will not be allowed outside the cab or else the cab interior must

also be cleaned and disinfected. • The tires and wheel wells must also be cleaned and disinfected before

leaving the premises within the Control Area.

4.3.2 Non-pasteurized Liquid Egg Products

Non-pasteurized Liquid Egg Products are considered to be of negligible risk based on USDA-APHIS CEAH risk assessment and may move in officially FSIS sealed vehicles per 9 CFR Chapter III Part 590.410 from breaking operations within the Control Area directly to pasteurization plants located within or out of the Control Area by a permit.





*See Attachment B for more information.

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4.3.3 Washed and sanitized Shell Eggs

x. Washed and sanitized (100–200 parts per million (ppm) chlorine solution) Shell Eggs moving to a premises without poultry and destined for food service, retail marketing, further processing, or for breaking are considered to be of negligible risk based on USDA-APHIS CEAH risk assessment and may be moved out of the Control Area by a permit. These eggs must meet the requirements in section 2.3.3 before being moved into market channels for human consumption.




leaving the premises within the Control Area. Product Specific Biosecurity for Washed and Sanitized Eggs being moved to a premises without poultry: • The transport vehicle shall be sealed by farm or company personnel under

the authorization of the Incident Command.

y. Washed and sanitized (100–200 ppm chlorine solution) Shell Eggs moving to a premises with poultry are considered to be of low risk on USDA-APHIS CEAH risk assessment and may be moved out of the Control Area by a permit.




leaving the premises within the Control Area. Product Specific Biosecurity for Washed and Sanitized Eggs being moved to a premises with poultry: • The transport vehicle shall be sealed by farm or company personnel under

the authorization of the Incident Command. • Egg handling materials used in the transport of eggs to breaking or further

processing plants must be destroyed at the final destination or cleaned, sanitized (following accepted procedures) and returned to the premises of origin without contacting materials going to other premises.

* See Attachment B for more information.

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4.3.4 Nest Run Shell Eggs

Nest Run Shell Eggs (not washed and sanitized) are considered to be of low risk on USDA-APHIS CEAH risk assessment and may be moved out of the Control Area by a permit.




leaving the premises within the Control Area. Product Specific Biosecurity for Nest Run Shell Eggs being moved to a premises without poultry: • Must be moved directly and only to a premises without poultry for

washing and sanitizing, breaking or for further processing. • The transport vehicle shall be sealed by farm or company personnel under

the authorization of the Incident Command. • Egg handling materials must be destroyed at the destination plant or

cleaned and sanitized (following accepted procedures). • Egg handling materials can be returned to the premises of origin after at

least 24 hours have elapsed since these materials were moved from the farm and, the 2 most recent RRT-PCR tests for all flocks on the premises were negative for HPAI and without contacting materials going to other premises.

• New paper or fiber flats must be used for hand gathered eggs.

4.3.5 Hatching Eggs

z. Hatching Eggs from Source Flocks tested negative for avian influenza (AI) virus by daily mortality sampling may be moved to hatcheries within the Control Area with a permit.




leaving the premises within the Control Area. Product Specific Biosecurity for Hatching Eggs Moved to Hatcheries Within the Control Area: • Egg handling materials must be destroyed at the hatchery or cleaned and

sanitized (following accepted procedures). • Egg handling materials can be returned to the premises of origin after at

least 24 hours have elapsed since these materials were shipped to the * See Attachment B for more information.

- 79 -

hatchery; the 2 most recent RRT-PCR tests for all flocks on the premises were negative for HPAI and without contacting materials going to other premises.

• New paper or fiber flats must be used for hand gathered eggs.

aa. Hatching Eggs from Monitored Premises tested negative for AI virus by daily mortality sampling may be moved out of the Control Area by permit.




leaving the premises within the Control Area. Product Specific Biosecurity for Hatching Eggs Moved Out of the Control Area: • Hatching eggs must then move directly and only to a hatchery or breaking

operation. • The chicks must be placed under “post-hatch” quarantine for 30 days. Egg

handling materials must be destroyed at the premises of destination or cleaned and sanitized (following accepted procedures).

• Egg handling materials can be returned to the premises of origin after at least 24 hours have elapsed since these materials were shipped to the hatchery; the 2 most recent RRT-PCR tests for all flocks on the premises were negative for HPAI and without contacting materials going to other premises.

• New paper or fiber flats must be used for hand gathered eggs. • The State Animal Health Official of the state of destination must be faxed

a copy of the restricted movement permit within 24 hours of issuance, and a permit is required to move within and out of the Control Area.

4.3.6 Day-Old Chicks

Day-Old Chicks from monitored flocks tested negative for AI virus by daily mortality sampling may be shipped by permit within or out of the Control Area.






- 80 -

Product Specific Biosecurity for Day-Old Chicks: • Must be placed under a 30 day quarantine. • The State Animal Health Official of the State of destination must be faxed

a copy of the restricted movement permit within 24 hours of issuance.

4.3.7 Broken Egg Shells

Broken Egg Shells on the farm or from breaking plants, pasteurization plants, and/or further processing plants may be moved by permit for drying using hot air to achieve conditions that will inactivate AI virus, disposal in an approved location, or for further processing using conditions that will inactivate the AI virus.




leaving the premises within the Control Area. Product Specific Biosecurity for Broken Egg Shells: • Farm or company personnel under the authorization of the Incident

Command shall seal the transport vehicle.

4.3.8 Inedible Egg

Inedible Egg from graders and/or breaking plants in a Control Area may move by permit for pasteurization or to approved waste disposal sites within or outside the Control Area.




leaving the premises within the Control Area. The IC or designate will evaluate and approve the risk assessment and risk mitigation procedures necessary to move products by permit. A permit must be issued by the incident command and seals placed on the vehicle by a state or federal regulatory official or a person authorized by the IC. Then IC will authorize procedures to break the seals outside of the Control Area with proper documentation.


- 81 -

4.4 Determination of Release of Movement Restrictions

4.4.1 All premises within the Control Area will be eligible for release from movement restrictions as determined by the Incident Command when:

bb. All infected flocks in a Control Area have been depopulated. All depopulated flock premises have been cleaned and disinfected. A minimum of 42 days have passed, or environmental sampling has proven HPAI virus negative status for the depopulated premises.

cc. All Contact Premises in a Control Area must have been depopulated or must have been monitored for 42 days.

4.5 References

• USDA-APHIS National Animal Health Emergency Management System (NAHEMS) Guidelines Response Strategies: Highly Contagious Foreign Animal Disease—January 2010

• An Assessment of the Risk Associated with the Movement of Pasteurized Liquid Egg and Its Products Into, Within, and Outside of a Control Area during a Highly Pathogenic Avian Influenza Outbreak, October 12, 2007. A Collaboration between the Egg Sector Working Group, the University of Minnesota’s Center for Animal Health and Food Safety, and USDA:APHIS:VS:CEAH

• An Assessment of the Risk Associated with the Movement of Nonpasteurized Liquid Egg (NPLE) and Its Products Into, Within, and Outside of a Control Area during a Highly Pathogenic Avian Influenza Outbreak, January 16, 2009. A Collaboration between the Egg Sector Working Group, the University of Minnesota’s Center for Animal Health and Food Safety, and USDA:APHIS:VS:CEAH

• An Assessment of the Risk Associated with the Movement of Washed and Sanitized Shell Eggs Into, Within, and Outside of a Control Area during a Highly Pathogenic Avian Influenza Outbreak, October 10, 2009. A Collaboration between the Egg Sector Working Group, the University of Minnesota’s Center for Animal Health and Food Safety, and USDA:APHIS:VS:CEAH

Electronic copies of these risk assessments are available for review and downloading at the following:

• Secure Egg Supply website: http://www.secureeggsupply.com/ • FAD PReP website: https://fadprep.lmi.org

Or by contacting: National Center for Animal Health Emergency Management Veterinary Services Animal and Plant Health Inspection Service U.S. Department of Agriculture 4700 River Road, Unit 41

http://www.aphis.usda.gov/wps/portal/aphis/ourfocus/animalhealth?urile=wcm%3Apath%3A%2Faphis_content_library%2Fsa_our_focus%2Fsa_animal_health%2Fsa_emergency_management%2Fct_fadprep

- 82 -

Riverdale, Maryland 20732-1231 Telephone: (301) 734-8073 Fax: (301) 734-7817 E-mail: [email protected]

- 83 -

Appendix 2. Selected Sections of Model Cleaning and Disinfection Guidelines from the Draft USDA-APHIS-VS Secure Egg Supply Plan

Appendix 2.1: Plastic Egg Packing Materials

Egg Packing Materials Plastic Flats, Pallets, Dividers

Company Name: Facility location where used:

Employee signature: Supervisor/trainer signature:

Time of the Day: Date:

These procedures are recommending minimum steps for cleaning and disinfection of plastic washable egg handling materials. Alternative procedures achieving the cleaning and disinfection objectives may be used as required by specific circumstances. Disinfectants: Appendix A below lists EPA registered disinfectants with label claims as avian flu disinfectants. Disinfectants should be used following the manufacturer’s directions for concentration and for contact time. Disinfectants should be applied to clean surfaces. Each operator should evaluate drying time post disinfectant application to ensure prescribed contact time is achieved. Mechanical washing and sanitation of plastic (impervious surfaces) egg handling materials: Pre-Operation:

1. Confirm equipment is clean and ready for operation. 2. Ensure that water levels are correct, temperature of wash water are at target temperature (90oF minimum), chemical supply lines for detergents and sanitizers are connected and that concentrations are at suppliers (equipment) recommendations, and that fresh water supply line is open. 3. Record and sign Operation Log noting date/time, temperature of wash and rinse, detergent concentration, and chlorine concentration in rinse.

Operation: 1. Introduce washable flats, pallets and dividers (tic-tacs) into washing system when all preoperation checks are successfully completed. 2. Maintain Operating Log noting temperature of wash and rinse waters, detergent and chlorine concentrations, and condition of wash water for excessive foaming and build-up of egg. Note: systems using manual addition of detergents will require frequent monitoring for detergent/chemical strength compared to systems using on-line monitoring of detergent concentration. Chlorine in rinse must be at or above 50 ppm and less than 100ppm.

- 84 -

3. Visually inspect after cleaning and disinfection to confirm they are free of egg or other organic soil. If not clean, use a brush on observed areas and repeat cleaning/sanitation cycle to completely removal of observed organic matter. 4. Make corrective changes as required to operate system within established ranges for temperature and chemical concentrations. Note and record in operating log corrective actions. 5. At mid-shift, drain wash water tank and perform mid-shift cleaning. 6. Repeat pre-operational checks before starting operations.

Manual cleaning and disinfection of plastic (impervious surfaces) egg handling materials: Pre-Operation

1. Review Appendix A for suitable disinfectants. 2. Assembled appropriate equipment (personal protective equipment, brushes, high-

pressure washer, low-pressure spray or foaming equipment for sanitizer application) and prepare detergent and sanitizer solutions following manufacturer’s directions.

3. Maintain Operating Log noting temperature of wash and rinse waters, detergent and sanitizer concentrations.

Operation: 1. Dry clean by brushing or scraping to remove accumulated organic matter and soil.

2. Wash with detergent solution using brushes or high-pressure washer and rinse with clean water.

3. Inspect for cleanliness and repeat wash procedure if not clean. 4. Apply sanitizing solution and allow sanitizing surfaces to dry. Additional Procedures and Documentation Required when Operating in Control Area or Receiving Eggs from Flocks in a Control Area defined by either State Veterinarian Office and/or APHIS Veterinary Representative:

1. Procedures for maintaining materials by flock of origin. 2. Documentation confirming segregation of materials and return to origin if used. 3. Cleaning and disinfection procedures in cases where they have and handle non-

washable type of materials in case of a Disease (AI, NDV) Outbreak. 4. Egg Handling Materials Cleaning and Disinfection Report form that documents the

sanitation and segregation procedures.

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Appendix 2.2: Paper, Cardboard and Wood Egg Packing Materials

Egg Packing Materials Paper Flats, Corrugated Cases, Wood Pallets, Dividers



Date: Time:

Paper Flats and Corrugated Cases

All paper flats and corrugated egg handling materials moving from control areas under permit will be segregated at receiving plant and disposed by incineration or other approved methods determined suitable for local circumstances.

Operation: Cleaning and Disinfection of wood based egg handling materials 1. Wood based egg handling materials will be washed using a detergent to remove all

visible egg material, manure, and feathers. 2. Visual inspection after cleaning of these materials to be free of egg or other organic

soil. If not clean, use a brush on observed areas and repeat cleaning/sanitation cycle to completely removal of observed organic matter.

3. Disinfect the cleaned materials using an approved disinfectant. 4. Maintain an Operating Log noting temperature of wash and rinse waters, detergent

and disinfectant used. Post Operation:

1. Dry cleaned and disinfected wood egg handling materials palletized on clean pallet and clearly labeled as Cleaned & Disinfected including date and time. Additional labeling may be required when the cleaned and disinfected materials are to be returned to the farm of origin.

2. Cleaned and disinfected materials should be stored in a dry area separate from those used for incoming shell eggs and unwashed egg handling materials.

Additional Procedures and Documentation Required when Operating in Control Area or Receiving Eggs from Flocks in a Control Area defined by either State Veterinarian Office and/or APHIS Veterinary Representative:

1. Procedures for maintaining materials by flock of origin. 2. Documentation confirming segregation of materials and return to origin if used. 3. Cleaning and disinfection procedures in cases where the farm has handled non-

washable type of materials in case of a Disease (AI, NDV) Outbreak. 4. Egg Packing Materials Cleaning and Disinfection Report which documents sanitation

and segregation procedures.

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Appendix 2.3: Truck Sanitation Procedure

Shell Egg Truck Exterior/Interior Wash Procedure



Date: Time:

Truck Sanitation Procedure

1. Clean interior of trailer to remove organic material. 2. Apply an appropriate disinfectant selected from EPA registered materials* to the

interior of the trailer being sure to cover all surfaces. A portable mister may work well for this purpose.

3. Allow surfaces to air dry for 20 minutes. 4. If the driver leaves the cab, all surfaces on the interior of the cab will need to be

disinfected with an appropriate disinfectant selected from EPA registered materials* applied using a clean rag or sponge. Surfaces include: steering wheel, dash, floorboards and seats.

5. The driver will then proceed to the nearest pre-approved truck wash to clean the exterior and undercarriage of the truck and trailer.

6. Driver must identify the truck wash they will proceed to and sign the cleaning certificate.

*EPA registered materials: http://www.epa.gov/pesticides/factsheets/avian_flu_products.htm

- 87 -

Shell Egg Exterior/Interior Cleaning Certificate

Must be used during elevated or highest biosecurity conditions

Date:_____________ Company Location : _____________________________ Time:___________________ Supplier:___________________________ Truck Line:__________________________ Trailer No or license plate number of trailer:___________________ Interior of trailer disinfected using:______________________at__________________% solution Interior of trailer disinfected by:_________________________________(signature) Interior of cab disinfected using:_______________________at___________________% solution Interior of cab disinfected by:___________________________________(signature) Truck wash location:___________________________ Driver initials:____________________ One copy to go with the driver - One copy to stay with location paperwork

- 88 -

Appendix 2.4: Loading Docks Receiving Shell Eggs From Control Areas

Loading Docks Receiving Shell Eggs From Control Areas



Time of the Day: Date:

These procedures are recommended for managing and for cleaning and disinfection of loading docks receiving shell eggs moving under permit from an AI Control Zone. General This recommendation assumes that the following Cleaning and Disinfection procedures are incorporated into the Loading Dock management and cleaning and disinfection procedure: Egg Packing Materials Plastic Flats, Pallets, Dividers and Materials Constructed of Wood (Pallets, Divider Board, Tic-Tacs) Shell Egg Truck Exterior/Interior Wash Procedure Moving Hatching Eggs Out of an AI Control Area This recommended procedure may be used for loading docks that may have dual use for receiving eggs for processing or hatching and also shipping processed product from the premise. The procedure is also recommended for loading docks that are dedicated for raw materials (shell eggs for processing or eggs for hatching). Procedure

1. During an emergency where an AI Control Zone has been established, the premises will not accept deliveries of eggs from a Control Zone unless the shipment of the eggs is conducted as allowed by Permit by relevant veterinary authorities.

2. The farm or facility where the eggs originate will not load the eggs for shipment until a permit to move is obtained and a scheduled receiving time is provided by the receiving premises.

3. The receiving premises should schedule arrival of eggs under permit so that they are received at the end of a processing day so that they may be processed as the “last eggs” handled that day before full cleaning and disinfection of the processing premises and equipment.

4. The receiving premises will receive the eggs at the scheduled delivery time.

- 89 -

a. Eggs arriving at the premises must stay on the unopened truck until authorized by receiving premises to approach the loading dock.

b. Before unloading, documentation of the origin and quantity of eggs must be reviewed and agree with the information contained in the permit for movement.

c. Eggs will be off-loaded and moved to segregated storage and /or preferably immediately processed (converted to liquid egg for pasteurization, washed and sanitized, or cooked).

5. The shell egg truck will be cleaned and disinfected following the above procedure before leaving the premises.

6. Egg handling materials will be cleaned and disinfected following the above procedures for egg handling materials or as described in the hatching egg procedure.

7. The loading dock area, receiving storage areas and connecting passages will be cleaned and disinfected.

a. Review Appendix A included in egg materials cleaning and disinfection procedure for suitable disinfectants.

b. Assemble appropriate equipment (personal protective equipment, brushes, high-pressure washer, low-pressure spray or foaming equipment for sanitizer application) and prepare detergent and sanitizer solutions following manufacturers directions.

c. Maintain Operating Log noting temperature of wash and rinse waters, detergent and sanitizer concentrations.

d. Dry clean by brushing or scraping to remove accumulated organic matter and soil.

e. Wash with detergent solution using brushes or high-pressure washer and rinse with clean water.

f. Inspect for cleanliness and repeat wash procedure if not clean. g. Apply sanitizing solution and allow sanitizing surfaces to dry.

- 90 -

Appendix 3. Example Industry Description of Organization and Tracking of Nest Run Shipments Egg Sector Working Group Draft I. Receiving Nest Run Eggs Off-Line A. Nest run eggs are received in individual shipments. Normally the nest run eggs are shipped in truck load quantities. When an entire truck load is from a single production source and date, that truckload may be designated as a single “lot.” If the load of eggs vary in source and/or production date, more than one lot number may be assigned to the eggs from a single truck load of nest run eggs. Regardless of the shipment composition, each receiving plant is required to have a system in place to track receipt, storage, processing and shipment of the finished goods.

B. Each shipping unit (skid or rack) must be identified as to the farm of origin and date of production.

C. Each shipment or “lot” must be placed within the receiving cooler to maintain its identity and prevent co-mingling with other nest run eggs. Each lot of eggs must maintain its farm of origin labeling within the receiving cooler.

Appendices 3.1 and 3.2 contain additional details concerning configurations of nest run shipments and the definition/tracking of an incoming lot of eggs. II. Processing of Nest Run Eggs A. Each skid or rack of nest run eggs will be tracked through processing and handling so that shipment of table eggs or egg products to the distribution warehouse, further processor or end user is known. This information is maintained by the processor so that it is retrievable in the event of a future need.

B. Once the nest run egg material has been emptied of eggs, it is subjected to the processor’s approved Cleaning and Disinfection Procedures for egg packing materials.

C. Storage of the cleaned and disinfected materials requires locating the material within the designated storage area. Some processors will maintain producer material source identity as a distinct unit, clearly labeled with its farm of origin identification as a day-to-day practice. To help prevent co-mingling with other clean material, stacks of materials may be shrink wrapped and labeled or “lots” of material segregated with marking tape. Other producers will segregate materials if the eggs are from an outside supplier rather than a contract or company owned facility; or if there is a need for a heightened level of biosecurity. III. Return Shipping of Nest Run Egg Packing Material A. The cleaned and disinfected materials shall be returned to the farm of origin or a farm within the system and not be co-mingled with other materials or egg products during transport. Appendix 3.3 contains additional details concerning outgoing shipments of egg packing materials. Appendix 3.1: Configurations of nest run shipments: Nest run eggs (NR’s) are sold to the market are shipped in truck load quantities. This is normally true of closed loop systems (contract or company owned farms ship to contract or company owned plant) as well. Market purchased eggs are usually packed on cardboard flats, cardboard divider boards and wooden grocery pallets but could be shipped on plastic flats, with wood or plastic boards and plastic or wood pallets.

- 91 -

Some farms do use egg racks, plastic flats, wood boards to stack the flats to ship to their processing plant. This could occur on market purchases, but shipping costs would preclude this practice on a large scale. Appendix 3.2: Definition/tracking of an incoming lot of eggs The processing plant will have a system in place to determine how they designate a lot of incoming eggs.

• Some producers will designate all eggs received on a single truck as one lot. Other producers may define a set number (X) of pallets as a lot. For example, they may consider one lot to consist of 10 pallets of eggs (regardless of source or pack date) and move these 10 pallets through their processing plant as a unit and trace them through distribution channels in this way.

• A producer may also designate each pack date as a single lot. In the case of multiple pack dates received on a single truck, an equal number of multiple lots will be defined.

• It is also possible that a single truck can carry eggs from more than one farm. In this case, eggs from each individual farm would each be considered a lot; the entire truck could be considered a single lot; or the truck load could be divided into “X” number of pallets based on pallet count.

• There may also be multiple lots from a single farm on a single truck if for example some of the eggs meet various product identity standards such as organic, free range, high omega and so on.

Appendix 3.3: Outgoing shipment or lot of material • Pallets are either plastic or wood block (36x48”) or wood grocery (40x48”) pallets. • Divider (separator) boards are plastic, wood or cardboard. • Flats are plastic or cardboard. • Tic-tacs are wood or cardboard. NR’s shipped as open market purchases are usually on cardboard flats. These flats are normally single use. The divider boards are single use cardboard also. The NR’s are normally shipped on “grocery” pallets. The received set of grocery pallets are exchanged for an equal number of pallets already at the processing location. It is these pallets that are sent back to the supplier as part of a material exchange program rather than the pallets physically received with the NR’s. When plastic flats are used along with either plastic or wood pallets and plastic or wood divider boards, as part of a market purchase, those flats, pallets and boards are returned to the producing farm. Whether or not the same material is returned back to the farm is pre-determined prior to shipping the NR’s. In a closed loop system, where one processing plant is served by a number of contract producer farms, the flats, pallets and boards are returned to either the same producer or to another producer in the group.

- 92 -

Appendix 4. Registered Antimicrobial Products with Label Claims for Avian (Bird) Flu Disinfectants Source: http://www.epa.gov/pesticides/factsheets/avian_flu_products.htm Current as of July 13, 2007

Registration

NumberProduct Name

*Active

IngredientFormulation Type

**Manufacturer Contact

Information

106-72 Maxima 128 5, 9, 10, 19 soluble concentrate Brulin & Company, Inc.>

106-73 Maxima 256 5, 9, 10, 19 soluble concentrate Brulin & Company, Inc.

106-79 Broadspec 256 5, 9, 10, 19 soluble concentrate Brulin & Company, Inc.

106-81 Maxima RTU 5, 9, 10, 19 solution-ready to use Brulin & Company, Inc.

134-65 DC&R Disinfectant 2, 7, 12 soluble concentrate Hess & Clark, Inc.

211-25 Pheno Cen Germicidal Detergent 17, 20, 24 soluble concentrate Central Solutions, Inc.

211-32 Pheno Cen Spray Disinfectant 11, 16 pressurized liquid Central Solutions, Inc.

211-50 Q5.5-5 NPB 2.5 HW 5, 9, 10,19 soluble concentrate Central Solutions, Inc.

211-62 Low pH Phenolic> 1, 16 soluble concentrate Central Solutions, Inc.

303-91 Hi-Tor Plus Germicidal 5, 9 soluble concentrate Huntington Professional

464-689 Ucarsan Sanitizer 420 13 soluble concentrate The Dow Chemical Company

464-696 Ucarsan Sanitizer 4128 13 soluble concentrate The Dow Chemical Company

464-700 Ucarcide 14 Antimicrobial 5, 13 solution-ready to use The Dow Chemical Company

464-702 Ucarcide 42 Antimicrobial 5, 13 solution-ready to use The Dow Chemical Company

464-715> Ucarsan 442 Sanitizer 5, 13 soluble concentrate The Dow Chemical Company

464-716 Ucarsan 414 Sanitizer 5, 13 soluble concentrate The Dow Chemical Company

777-72 Biosol 5, 11 Ready to Use Liquid Reckitt Benckiser

1043-91 LpH Master Product 3, 16 soluble concentrate Steris Corporation

1677-129 Oxonia Active 15, 21 soluble concentrate Ecolab, Inc.

1677-158 Vortexx 14, 18, 21 soluble concentrate Ecolab, Inc.

1677-203 OxySept LDI 14, 21 soluble concentrate Ecolab, Inc.

1839-86 BTC 2125 M 10% Solution 4, 6 soluble concentrate Stepan Company

1839-95 NP 4.5 (D &F)

Detergent/Disinfectant

4, 6 Soluble concentrate Stepan Company

1839-154 Scented 10% BTC 2125M

Disinfectant

4, 6 soluble concentrate Stepan Company

1839-155 BTC 2125M 20% Solution 4, 6 soluble concentrate Stepan Company

1839-173 7.5% BTC 885 Disinfectant 5, 9, 10, 19 soluble concentrate Stepan Company

3838-36 Quat 44 4, 6 soluble concentrate Essential Industries, Inc.

3838-37 Quat Rinse 4, 6 soluble concentrate Essential Industries, Inc.

3862-177 Tek-Trol Disinfectant 1, 3, 16 soluble concentrate ABC Compounding Co.

5813-1 Clorox 30 Soluble concentrate Clorox Company

6659-3 Spray Nine 4, 6 Ready to Use Liquid Spray Nine Corporation

6836-70 Bardac 205M-7.5B 5, 9, 10, 19 soluble concentrate Lonza, Inc.

6836-71 Lonza Formulation Y-59 5, 9, 10, 19 soluble concentrate Lonza, Inc.

6836-75 Lonza Formulation S-21 5, 10, 11, 21 soluble concentrate Lonza, Inc.

6836-77 Lonza Formulation S-18 5, 10, 11, 21 soluble concentrate Lonza, Inc.

6836-78 Lonza Formulation R-82 > 5, 9, 10. 19 soluble concentrate Lonza, Inc.

6836-136 Lonza Formulation S-18F 5, 9, 10, 19 soluble concentrate Lonza, Inc.

6836-139 Lonza Formulation R-82F 5, 9, 10, 19 soluble concentrate Lonza, Inc.

6836-140 Lonza Formulation S-21F 5, 9, 10, 19 soluble concentrate Lonza, Inc.

*See end of table for active ingredients key

- 93 -

Registration

NumberProduct Name

*Active



Information

6836-152 Lonza Formulation DC-130 5, 9, 10, 19 solution-ready to use Lonza, Inc.

6836-233 Bardac 205M-50 5, 9, 10, 19 soluble concentrate Lonza, Inc.

6836-252 Phencide 256 1, 16 soluble concentrate Lonza, Inc.

6836-253 Phenocide 128 1, 16 soluble concentrate Lonza, Inc.

6836-266 Bardac 205M-10 5, 9, 10, 19 soluble concentrate Lonza, Inc.

6836-277 Bardac 205M 1.30 5, 9, 10, 19 soluble concentrate Lonza, Inc.



6836-303 Bardac 205M 7.5B 5, 9, 10, 19 soluble concentrate Lonza, Inc.

8155-23 Husky 806 H/D/N 9 Soluble concentrate Canberra Corporation

8383-3 Sporicidin Brand Disinfectant

solution

22, 31 Ready to use Liquid Sporicidin International

70060-19 Aseptrol S10-Tabs 27, 28 Pellet/tablet Engelhard Corporation

70144-1> Opticide-3 4, 6 Ready to Use Micro-Scientific Industries

71654-7 Virkon 21, 22 Pellet/tablet DuPont Chemical Solutions

74331-2 DisinFx 8, 23, 14 Ready to use Liquid SteriFx Inc.

74559-1 Accel TB 13 Ready-to-Use Liquid Virox Technologies

10324-56 Maquat 256 4, 6 soluble concentrate Mason Chemical Company




10324-67 Maquat MQ615-AS 5, 8, 9, 17 soluble concentrate Mason Chemical Company

10324-72 Maquat 615 HD 5, 9, 10, 19 soluble concentrate Mason Chemical Company

10324-80 Maquat 5.5M 5, 9, 10, 19 soluble concentrate Mason Chemical Company

10324-81 Maquat 705M 5, 9, 10, 19 soluble concentrate Mason Chemical Company

10324-85 Maquat 86 M 5, 9, 10, 19 solution-ready to use Mason Chemical Company

10324-94 Maquat 20M 4, 6 soluble concentrate Mason Chemical Company

10324-96 Maquat 50DS 4, 6 soluble concentrate Mason Chemical Company


10324-115 Maquat 750 M 5, 9, 10, 19 soluble concentrate Mason Chemical Company

10324-117 Maquat 710 M 5, 9, 10,19 soluble concentrate Mason Chemical Company

10324-118 Maquat 256 EBC 4, 6 soluble concentrate Mason Chemical Company



10324-131 Maquat A 5, 9, 10, 19 soluble concentrate Mason Chemical Company

10324-141 Maquat 256-NHQ 5, 9 Soluble concentrate Mason Chemical Company

10324-142 Maquat MQ2425 M 14 4, 6 soluble concentrate Mason Chemical Company

10324-143 Maquat 10B 4, 6 soluble concentrate Mason Chemical Company

10324-145 Maquat FP 4, 6 soluble concentrate Mason Chemical Company

10324-162 Maquat 2420 Citrus 5, 9 soluble concentrate Mason Chemical Company

10324-164 Maquat 256 PD 4, 6 soluble concentrate Mason Chemical Company

11600-4 Sanox II 5, 9, 10, 19 soluble concentrate Conklin Co., Inc.

47371-6 Formulation HS 652Q 5, 9 soluble concentrate H&S Chemicals Division

47371-7 Formulation HS 821Q 5, 9 soluble concentrate H&S Chemicals Division

47371-36 HS-867Q 5, 9 soluble concentrate H&S Chemicals Division

HS-267Q

germicidal Cleaner

47371-141 Formulation HH 652Q 5, 9 soluble concentrate H&S Chemicals Division

47371-37 5, 9 soluble concentrate H&S Chemicals Division

- 94 -

Registration

NumberProduct Name

*Active



Information

56392-7 Dispatch Hospital Cleaner with

Bleach

30 Ready to use Liquid Caltech Industries

56392-8 Dispatch Hospital Cleaner

Disinfectant Towels with Bleach

30 Ready to use Towelette Caltech Industries

61178-1 D-125 4, 6 soluble concentrate Microgen Inc.

61178-2 Public Places 4, 6 solution-ready to use Microgen Inc.

61178-4 Public Places Towelette 4, 6 impregnated materials Microgen Inc.

61178-5 CCX-151 4, 6 soluble concentrate Microgen Inc.

61178-6 D-128 4, 6 soluble concentrate Microgen Inc.

63761-8 Sterilex Ultra Disinfectant Cleaner 4, 6, 15 Soluble concentrate Sterilex Corporation

66171-1 Advantage 256 1, 3, 16 soluble concentrate Preserve International

66171-6 Dyne-O-Might 32 soluble concentrate Preserve International

66171-7 Synergize 7, 13 soluble concentrate Preserve International

66243-1 Odo-Ban Ready to Use 5 solution-ready to use Clean Control Corporation

66243-2 Odo-Ban 5 soluble concentrate Clean Control Corporation

66243-3 Quik Control 5, 9, 10, 19 soluble concentrate Clean Control Corporation

67619-8 CPPC Ultra Bleach 2 30 Soluble concentrate Clorox Professional Services

Company67619-9 PJW-622 4, 6 impregnated materials Clorox Professional Products

Co.67619-13 CPPC Storm 30 Ready to use Liquid Clorox –professional Services

Company70144-2 Opticide-3 wipes 4, 6> Ready to Use Towelette Micro-scientific Industries

70263-6 Microban QGC 5, 9, 10, 19 soluble concentrate Microban Systems, Inc.

70263-8 Microban Professional 5, 9, 10, 19 solution-ready to use Microban Systems, Inc.

70627-2 Disinfectant DC 100 4, 6 solution-ready to use Johnson Diversey, Inc.

70627-6> Phenolic Disinfectant HG 1, 16 soluble concentrate Johnson Diversey, Inc.

70627-10 Johnson’s Forward Cleaner 5 soluble concentrate Johnson Diversey, Inc.

70627-15 Johnson’s Blue Chip Germicidal 5 soluble concentrate Johnson Diversey, Inc.

70627-21 Virex II 128 5, 9 soluble concentrate Johnson Diversey, Inc.

70627-22 Virex RTU 5, 9 solution-ready to use Johnson Diversey, Inc.



71355-1 Virocid 5, 10, 15 soluble concentrate CID Lines, NV/SA

71654-6 Virkon S 25, 26 soluble concentrate DuPont Chemical Solutions

71847-2 Klor-Kleen 29 pelletted/tabletted Medentech, Ltd.

81073-1 Peridox 15, 21 soluble concentrate Clean Earth Technologies,

- 95 -

* Active

IngredientActive Ingredient Key

1 2-Benzyl-4-chlorophenol (62201)

2 2-(Hydroxymethyl)-2-nitro-1,3-propanediol

(83902)3 4-tert-Amylphenol (64101)

4 Alkyl dimethyl benzyl ammonium chloride

(60%C14, 30%C16, 5%C18, 5%C12) (69104)5 Alkyl dimethyl benzyl ammonium chloride

(50%C14, 40%C12, 10%C16 ) (69105)6 Alkyl dimethyl ethylbenzyl ammonium chloride

(68%C12, 32%C14) (69154)7 Alkyl dimethyl benzyl ammonium chloride

(67%C12, 25%C14, 7%C16, 1%C18) (69175)8 Citric Acid

9 Didecyl dimethyl ammonium chloride (69149)

10 Dioctyl dimethyl ammonium chloride (69166)

11 Ethyl alcohol (1501)

12 Formaldehyde (43001)

13 Glutaraldehyde (43901)

14 Hydrochloric Acid

15 Hydrogen peroxide (595)

16 o-Phenylphenol (64103)

17 o-Phenylphenol, potassium salt (64108)

18 Octanoic acid (128919)

19 Octyl decyl dimethyl ammonium chloride (69165)

20 p-tert-Amylphenol, potassium salt (64111)

21 Peroxyacetic acid (63201)

22 Phenol

23 Phosphoric Acid

24 Potassium 2-benzyl-4-chlorophenate (62202)

25 Potassium peroxymonosulfate (63604)

26 Sodium chloride (13905)

27 Sodium chlorites

28 Sodium dichloroisocyanurate dihydrate

29 Sodium dichloro-s-triazinetrione (81404)

30 Sodium hypochlorite

31 Sodium phenate

32 Iodine

- 96 -

Appendix 5. Efficacy Data Requirements for Virucides Source: http://www.epa.gov/oppad001/dis_tss_docs/dis-07.htm Accessed on June 29, 2010

DIS/TSS-7 / Nov. 12, 1981 EFFICACY DATA REQUIREMENTS:

VIRUCIDES

(Proposed method prepared by Registration Division,

Office of Pesticide Programs, EPA, 1976)

The Agency will accept adequate data developed by any virological technique which is recognized

as technically sound, and which simulates to the extent possible in the laboratory the conditions

under which the product is intended for use. For virucides whose use-directions identify the

product as one intended for use upon dry, inanimate, environmental surfaces (such as floors,

tables, cleaned and dried medical instruments, etc.), carrier methods, which are modifications of

either the AOAC Use-Dilution Method (for liquid surface disinfectants) or the AOAC Germicidal

Spray Products Test (for surface spray disinfectants), must be used in the development of the

virological data. To simulate in-use conditions, the specific virus to be treated must be inoculated

onto hard surfaces, allowed to dry, and then treated with the product according to the directions

for use on the product label. One surface for each of two different batches of disinfectant must be

tested against a recoverable virus titer of at least 104 from the test surface (petri dish, glass slide,

steel cylinder, etc.) for a specified exposure period at room temperature. The virus is then

assayed by an appropriate virological technique. The protocol for the viral assay must provide the

following information:

i. The virus recovery from a minimum of 4 determinations per each dilution in the assay system (tissue culture, embryonated egg, animal infection, or whatever assay system is employed).

ii. Cytotoxicity controls: The effect of the germicide on the assay system from a minimum of 4 determinations per each dilution.

iii. The activity of the germicide against the test virus from a minimum of 4 determinations per each dilution in the assay system.

iv. Any special methods which were used to increase the virus titer and to detoxify the residual germicide.

v. The ID-50 values calculated for each assay.

vi. The test results shall be reported as the reduction of the virus titer by the activity of the germicide (ID-50 of the virus control less the ID-50 of the test system), expressed as log10 and calculated by a statistical method (Reed and Muench, 1938; Litchfield and Wilcoxon, 1949; as examples).

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vii. For virucidal data to be acceptable, the product must demonstrate complete inactivation of the virus at all dilutions. When cytotoxicity is evident (as in attached tables) at least a 3-log reduction in titer must be demonstrated beyond the cytotoxic level. The calculated viral titers must be reported with the test results.

A typical laboratory report of a single test with one virus (recovered from a treated surface)

involving a tissue culture, therefore, would include the details of the methods employed and the

information in the attached tables.

Claims of virucidal activity for a product must be restricted to those viruses which have actually

been tested. Separate studies on two batches of product are required for each virus.

References

Litchfield, J. T., Jr., and F. Wilcoxon. 1949. A simplified method of evaluating dose-effect

experiments. Jour. Pharma. Exp. Therapy, 96: 99-113.

Reed, L. J., and H. Muench. 1938. A simple method of estimating 50 per cent end-points. Amer.

Jour. Hygiene, 27: 493-497.

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Appendix 6. Virucide Test Results Source: http://www.epa.gov/oppad001/dis_tss_docs/dis-07table.htm Accessed on 29 June, 2010 Table I shows sample test results for the toxicity of the disinfectant on live tissue or cells without virus added. The purpose is to be certain the log reduction of virus is due to activity of the disinfectant on the virus rather than death of the cells. Table 1 - Test Results Dilution of Virus

Virus - Disinfectant*

Virus - Control*

Cytotoxic-Control

10-1 TTTT ++++ TTTT

10-2 TTTT ++++ TTTT

10-3 T000 ++++ T000 10-4 0000 ++++ 0000

10-5 0000 ++++ 0000 10-6 0000 +++0 0000

10-7 0000 +000 0000 10-8 0000 0000 0000 *Recovery of virus from surfaces demonstrated by cytopathogenic effect, fluorescent antibody, plaque count, animal’s response, or other recognized acceptable technique. Note: T = toxic; + = virus recovered; 0 = no virus recovered. Table II-Calculation of the Tissue Culture Infective Dose 50 (TCID50) Values Accumulated

Values

Virus Dilution Inoculated

No. Infected / No. Inoculated

No. Infected

No. Not Infected No. Infected No. Not

Infected

No. Infected / No. Inoculated

Percent Infected

10-1 4/4 4 0 24 0 24/24 100 10-2 4/4 4 0 20 0 20/20 100 10-3 4/4 4 0 16 0 16/16 100 10-4 4/4 4 0 12 0 12/12 100 10-5 4/4 4 0 8 0 8/8 100 10-6 3/4 3 1 4 1 4/5 80 10-7 1/4 1 3 1 4 1/5 20 10-8 0/4 0 4 0 8 0/8 0 TCID50 = 106.5

- 99 -

Table III-Calculation of the Tissue Culture Lethal Dose 50 (TCLD50) Values Accumulated

Values

Virus Dilution Inoculated

No. Toxic / No. Inoculated

No. Toxic

No. Not Toxic

No. Toxic No. Not Toxic

No. Toxic / No. Inoculated Percent Toxic

10-1 4/4 4 0 9 0 9/9 100 10-2 4/4 4 0 5 0 5/5 100 10-3 1/4 1 3 1 3 1/4 25 10-4 0/4 0 4 0 7 0/7 0 10-5 0/4 0 4 0 11 0/11 0 10-6 0/4 0 4 0 15 0/15 0 10-7 0/4 0 4 0 19 0/19 0 10-8 0/4 0 4 0 23 0/23 0 TCLD50 = 102.7 Therefore: Virus inactivation = TCID50 - TCLD50 = 103.8 log 10 Claims for virucidal activity for a product must be restricted to those viruses which have actually been tested.

- 100 -

Appendix 7. Expert Opinion on the Inactivation of Avian Influenza Appendix 7.1: Expert opinion on the Inactivation of Avian Influenza Virus

ERIC BENSON, Ph.D. Assistant Professor Bioresources Engineering Department University of Delaware DAVID HALVORSON, DVM Diplomate, ACPV Extension Veterinarian - Avian Health College Of Veterinary Medicine University of Minnesota DAVID SWAYNE, DVM, Ph.D. Laboratory Director Southeast Poultry Research Laboratory USDA/Agricultural Research Service

Questionnaire for Expert Opinion on the Inactivation of Avian Influenza Dr. Eric Benson

1) Physical and chemical inactivation

General Packing Materials

a. What degree of HPAI virus inactivation would be achieved on the following contaminated surfaces by washing with a detergent (Temperature > 90F, wash water replaced once per day)? Answer is to be expressed as log reduction in the viral titer. Experimental tests with detergents show that there is much better reduction in virus titer on plastic than on wood surfaces. The difference in reduction in virus titer between porous and nonporous surfaces is greater for detergents than for commercial detergents. The values in the table below show ‘room temperature’ results. Increasing the temperature of the applied solution will increase the efficacy of the treatment. Where practical, the wash water treatment temperature should be increased as high as practical during HPAI concern periods. Water temperatures of 17ºC and 28ºC show ability to maintain virus for considerable lengths of time (days).

Material type Maximum

(log inactivation) Minimum (log inactivation)

Most likely (log inactivation)

Plastic 5.0 (Tide with bleach > 6g/L)

2.9 (Tide without bleach)

2.5

- 101 -

Unpainted Wood

2.4 (Tide with bleach > 6g/L)

0 (Tide with bleach < 6g/L, Tide without bleach)

2.0

b. What degree of HPAI virus inactivation would be achieved on the following

contaminated surfaces using an EPA registered disinfectant against AI according to label directions for use on hard nonporous surfaces? With porous surfaces, there is a significant difference between recovery and inactivation. On porous wood surfaces, a portion of the virus cannot be easily recovered from the surface. In testing on dry basswood coupons, there was a drop in log titer from roughly 6.7 to 5.0 to 5.7, or about a 1.0 to 1.7 reduction in titer. There is considerable sample to sample variation in recovered virus titer on porous surfaces.

Material type Maximum (log inactivation)

Minimum (log inactivation)


Plastic 5.5 (Peroxygen Liquid)

1.9 (Quaternary Ammonia Compound / Foam – MDF200)

4.0

Unpainted Wood (dry)

5.5 (QAC/Oxidizer Foam)

1.2 Glutaraldehyde/QAC Fog

3.0

Unpainted wood (wet) Not tested

c. Estimate the degree of HPAI virus inactivation on the following contaminated surfaces

based on 24 hours of storage at a temperature less than 45 F?

Material type

Maximum (log inactivation)



Plastic Not tested Unpainted Wood (dry)

Not tested

Specific Questions for Wooden Materials

d. Which categories of disinfectants are recommendable for inactivation of HPAI virus on porous surfaces such as wood?

Disinfectants that tested well for LPAIV on wood include Peroxygen (Virkon S) applied as a liquid or foam (foam preferred to increase contact time) and Quaternary ammonia compound / Oxidizer foam (Sandia MDF-200). As an alternative during pandemic or similar, 3% or greater citric acid may be an acceptable alternative. Disinfectants that did not test well for LPAIV on wood include calcium hypocholorite and sodium hypochlorite.

e. Suppose one ml of egg content with 105 EID50/ml of AI virus leaks on to 1 cm2 area of

packaging material which is then cleaned with a detergent to ensure no visual organic matter. Estimate the following parameters.

To evaluate the question, a quick experiment was conducted. Fluid was drawn from a typical chicken egg, thoroughly mixed (or scrambled), and applied wet to basswood samples.

- 102 -

Remainder of egg fed to dog. 1 inch square grids were drawn on the basswood coupons. 1 ml, 2.5 ml, and 5 ml were applied to separate basswood coupons and allowed to dry for 1 hour. 5 ml applied egg solution overflowed the 1 inch square grid. The coupons were cleaned with commercial detergent and allowed to dry before visual inspection. After cleaning with detergent, there was a visible ring at the outside edge. The ring was between 0.5 mm and 1 mm thick. Inside the ring, most material was removed by detergent and agitation, with less than 0.25 mm remaining.

a) Average thickness of a potential layer of egg content on the cleaned surface in

millimeters. b) Viral titer on the area where egg content leaked initially in log EID50/cm2?

Maximum

log EID50/cm2 Minimum

log EID50/cm2 Most likely

log EID50/cm2

Viral titer on the material Not tested

2) Cross Contamination

a. Suppose a person touches a contaminated eggshell on the surface (Assume a viral titer of 102 EID50/cm2). Then what fraction of the virus present on the eggshell surface in contact with the hand is transferred on to the hand?

Maximum

(fraction) Minimum (fraction)

Most likely (fraction)

Fraction transferred Not tested b. Suppose a person with contaminated hand touches an egg packaging material (Assume a

viral titer of 102 EID50/cm2). What fraction of the virus present on the hand area in contact with the material is transferred to the material?




Plastic Unpainted Wood (dry)

Not tested

c Given that egg flats are loaded on to a conveyer belt for processing, what fraction of virus

on a contaminated flat is transferred to the next flat that is placed on the same area of the belt via cross contamination?

Maximum



Fraction transferred Not tested

Maximum (mm) Minimum(mm) Most likely (mm)

Thickness 1 mm <0.25 0.25 mm

- 103 -

3) Miscellaneous questions

a. How many times more likely is it for an HPAI contaminated egg with no visual defects to leak during transportation as compared to a virus free egg?

Maximum Minimum Most likely Number times more likely to leak during transportation

X10 X1 X5

Questionnaire for Expert Opinion on the Inactivation of Avian Influenza

Dr. David Halvorson



a. What degree of HPAI virus inactivation would be achieved on the following contaminated surfaces by washing with a detergent (Temperature > 90F, wash water replaced once per day)? Answer is to be expressed as log reduction in the viral titer.


(log inactivation) Minimum(log inactivation)


Plastic 3 1 2 Unpainted Wood

2 0 1


contaminated surfaces using an EPA registered disinfectant against AI according to label directions for use on hard nonporous surfaces?


(log inactivation) Minimum(log inactivation)


Plastic 3 1 2 Unpainted Wood (dry)

Unpainted wood (wet)

2 0 1






Plastic none Unpainted Wood (dry)

none

- 104 -


d. Which categories of disinfectants are recommendable for inactivation of HPAI virus on porous surfaces such as wood? No idea. Producer will probably use what he has access to and is safe to use around eggs.

e. Suppose one ml of egg content with 105 EID50/ml of AI virus leaks on to 1 cm2 area of

packaging material which is then cleaned with a detergent to ensure no visual organic matter. Estimate the following parameters.

a) Average thickness of a potential layer of egg content on the cleaned surface in

millimeters.


Thickness 1 0.1 0.5 b) Viral titer on the area where egg content leaked initially in log EID50/cm2?

After C&D(?)

Maximum



log EID50/cm2

Viral titer on the material 3 0 0



Maximum



Fraction transferred 50% 1% 10% b. Suppose a person with contaminated hand touches an egg packaging material (Assume a

viral titer of 102 EID50/cm2). What fraction of the virus present on the hand area in contact with the material is transferred to the material?




Plastic 50% 1% 10% Unpainted Wood (dry)

? ? ?

c. Given that egg flats are loaded on to a conveyer belt for processing, what fraction of

virus on a contaminated flat is transferred to the next flat that is placed on the same area of the belt via cross contamination?

Maximum



Fraction transferred 10% 1% 1%

- 105 -


a) How many times more likely is it for an HPAI contaminated egg with no visual defects to leak during transportation as compared to a virus free egg?


Here is my thinking: ~30% of “infected” eggs will be abnormal; of these, half will be soft shell or leakers and they will be discarded. The other half of the 30% will be thin shell and will crack or break at 10X a normal egg. The other 70% will crack or break at the same as a normal egg.

Questionnaire for Expert Opinion on the Inactivation of Avian Influenza David Swayne


I do not have answers to questions a-d, but they could be determined by simple experiments.


a. What degree of HPAI virus inactivation would be achieved on the following contaminated surfaces by washing with a detergent (Temperature > 90F, wash water replaced once per day)? Answer is to be expressed as log reduction in the viral titer.


Minimum(log inactivation)


Plastic Unpainted Wood


contaminated surfaces using an EPA registered disinfectant against AI according to label directions for use on hard nonporous surfaces?


Minimum(log inactivation)



Unpainted wood (wet)








d. Which categories of disinfectants are recommendable for inactivation of HPAI virus on porous surfaces such as wood?

- 106 -

e. Suppose one ml of egg content with 105 EID50/ml of AI virus leaks on to 1 cm2 area of packaging material which is then cleaned with a detergent to ensure no visual organic matter. Estimate the following parameters.

The crack would potentially be on the bottom so the leak would emit all the egg contents and not just 1 ml; might be 10-25 ml

a) Average thickness of a potential layer of egg content on the cleaned surface in millimeters.


Thickness 3 1 3 b) Viral titer on the area where egg content leaked initially in log EID50/cm2?

Maximum



log EID50/cm2

Viral titer on the material 4 1 2.5

Maximum concentration would be 5log10/ml but with 0.3 mm thickness the concentration would be less closer to 4 log10/cm2. The average titer of infected eggs would be less than the maximum. In our recent studies, the highest titer of virus is in the last egg laid and they had thinner shells, more likely to crack during handling and disposed on farm. Our average titer for HPAI virus in eggs was 2.38log10 EID50/ml so I averaged up to 2.5log10 EID50/ml



Maximum (fraction)

Minimum (fraction)


Fraction transferred 102.6 EID50 102.6 EID50

Too many variables to calculate, but individual transfer should be assume at maximum to be that from the sum of the individual fingers – such as 1 cm2 per finger x 5 fingers = 5 x102 or 102.6 EID50. The minimum would be <1log10 of dry and higher if wet. Most likely? <1/2 of maximum

b. Suppose a person with contaminated hand touches an egg packaging material (Assume a viral titer of 102 EID50/cm2). What fraction of the virus present on the hand area in contact with the material is transferred to the material?

Material type Maximum (fraction)

Minimum (fraction)


Plastic 50% 10% 25% Unpainted Wood (dry)

100% 10% 50%

c) Given that egg flats are loaded on to a conveyer belt for processing, what fraction of

virus on a contaminated flat is transferred to the next flat that is placed on the same area of the belt via cross contamination?

Maximum



Fraction transferred 50% 10% 25%

- 107 -


a. How many times more likely is it for an HPAI contaminated egg with no visual defects to leak during transportation as compared to a virus free egg?


400% 200% 400%

Appendix 7.2: Approach for Estimating Parameter Distribution based on Expert Opinion We estimated the parameter distributions for the expert opinion in two steps as follows:

Step 1: Parameter distributions were estimated separately based on each expert’s opinion. Step 2: Distributions estimated from individual expert’s opinions were combined to obtain the final parameter distribution.

We note that there are various alternate methods to combine expert opinion. Sampling from each expert’s opinion according to weights given to them was recommended over taking the average of both the experts’ opinions.56 The final parameter distribution in this case is a mixture distribution of the parameter distributions based on each expert’s opinion. We illustrate this approach for the following parameter: “degree of HPAI virus inactivation on unpainted wood by washing with a detergent”. The expert opinion on this parameter is summarized in Appendix 7 Table 1 below. We used a pert distribution to estimate the parameter distribution from individual experts. The pert distribution is frequently utilized to model expert opinion when only the minimum, maximum and most likely values of the distribution are known. Appendix 7 Table 1 Appendix 7 Table 2

Material type

Log EID50 inactivation on unpainted wood due to detergent washing

Individual distribution

Maximum Minimum Most likely Expert 1 2.4 0 2.0 Pert (0,2,2.4) Expert 2 2 0 1 Pert (0, 1, 2)

Material type Characteristics of the distributions for log EID50 inactivation on unpainted wood through detergent washing based on individual experts.

Mean Stdev 90 percent interval Expert 1 Pert (0,2,2.4) 1.7 0.40 (0.97-2.284)

Expert 2 Pert (0, 1, 2) 1 0.379 (.379-1.621)

- 108 -

Let the random variables representing expert1 and expert 2’s opinions be denoted by X1 and X2. Let Xcom denote the final parameter variable obtained by combining expert1 and expert 2’s opinions. We calculated Xcom utilizing the equation A7.1 below. We note the use of Binomial (1, 0.5) distribution for the indicator variable Y represents equal emphasis being placed on expert1 and expert 2’s opinions.

21 )1()( XYXYXcom

!+= (A7.1) Where, Y ~ Binomial (1, 0.5) We estimated the distribution based on the above approach and @RISK simulation for 20,000 iterations (Monte Carlo sampling). The resulting distribution (Appendix 7 Figure 1) for Xcom had a mean of 1.36 log EID50 and a 90 percent probability interval of 0.49-2.22 log EID50. The above methods were also used to estimate other parameter distributions from the expert opinion presented in Appendix 7.1 Appendix 7 Figure 1. Distribution for log EID50 inactivation on unpainted wood due to detergent washing based on expert opinion.

Distribution for Wood

Mean = 1.366771

X <=2.2295%

X <=0.495%

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.625 1.25 1.875 2.5

- 109 -

Appendix 8. Quantitative Results on Contamination of Egg Packing Materials at Nest Run Farms Appendix 8.1: Estimation of the number of HPAI virus contaminated leaking eggs This appendix provides details on the estimation of the number of HPAI contaminated leaking eggs moved from an infected but undetected flock. Data on the rates of leakage for normal virus free eggs, the estimated maximum daily number of internally contaminated eggs (Emax) from the simulation models presented in chapter 7, and expert opinion on the relatively greater likelihood that HPAI internally contaminated eggs leak were considered in our estimation. Notation Pfleak - Probability that a normal virus-free nest run egg is leaking after being packed onto egg flats at nest run premises. Ptleak - Probability that a normal virus-free nest run egg that is not leaking when it is packed on to egg flats, leaks during transportation. Pnleak - Probability that a normal virus-free nest run egg received at an off-line processing center is leaking. γ - Ratio of the probability that an HPAI virus contaminated egg leaks to the probability that a normal virus free egg leaks. Phleak - Probability of an HPAI virus-contaminated nest run egg received at an off-line processing center being a leaker (Phleak). Emax - estimated maximum daily number of contaminated eggs moved from an infected but undetected farm following the active surveillance protocol. Nhleak - Number of HPAI virus contaminated leaking eggs moved from an infected but undetected flock. Data Appendix 8 Table 1 Symbol Source Parameter Distribution Pfleak Egg industry expert opinion

(Section 8.2.2) Uniform(0.00125-.005)

Ptleak Lederer et al. (1978) Beta (90, 47912) (95 percent P.I. 0.0016-0.0022)

γ Avian influenza expert opinions (Appendix 7)

Simulation output distribution; mean 3.7 (90 percent P.I. 2.2-7).

Emax Disease transmission and surveillance models (chapter 7)

Simulation output distribution; mean 11 eggs (90 percent P.I. 0-44 eggs).

- 110 -

Model The parameter, Pnleak is a function of the probability that a virus free egg leaks either on farm (Pfleak) or during transportation (Ptleak) as shown in A8.1. The parameter γ was estimated through expert opinion using the methods described in Appendix 7.2. We modeled Nhleak as Binomial (Emax, Phleak). Emax is a random variable whose distribution was derived from the disease transmission and surveillance models presented in chapter 7. The distribution for Nhleak was estimated by simulating this model with @RISK for 20,000 iterations and Monte Carlo sampling.

)1)(1(1 tleakfleaknleak PPP !!!= (A8.1)

}1,.min{ !nleakhleakPP = (A8.2)

Nhleak ~Binomial(Emax, Phleak) (A8.3) Results The simulation output distributions from the above model are summarized in Appendix 8 Table 1. From these results, there is a 95 percent chance that the number of contaminated leaking eggs received at an offline processing center (Nhleak), is less than 1. Appendix 8 Table 1 Symbol Simulation Output Distribution Characteristics Pnleak mean 0.005; 90 percent P.I. 0.0033-0.0067 Phleak mean 0.018; 90 percent P.I., 0.008-0.037 Nhleak mean 0.18 eggs (95 percent P.I. 0-1) Appendix 8.2: Estimation of the number of soft shelled contaminated eggs Beard et al, found 3 out of 15 contaminated eggs laid by experimentally inoculated hens were thin shelled or soft shelled. We used a Beta (4, 13) as the distribution of Psoft, the probability that a HPAI internally contaminated egg is soft shelled. The number of HPAI contaminated from an infected but undetected flock that are soft shelled Nsoft was modeled as Binomial (Emax, Psoft) distribution. The distribution for Nsoft was estimated by simulating this model with @RISK for 20,000 iterations and Monte Carlo sampling. The final distribution for Nsoft had a mean 2.45 (90 percent P.I. 0-9) eggs.

- 111 -

Appendix 9. Quantitative Results on the Impact of Cleaning and Disinfection on Porous Packing Materials In this appendix, we estimate the overall degree of inactivation of HPAI virus on porous egg packing materials with washing and disinfection. The degree of HPAI virus inactivation with washing or disinfection individually was estimated from expert opinion as described in Appendix 7. Let Lwash be the degree of inactivation of HPAI virus on porous materials due to washing with detergent and Ldis be the degree of inactivation of HPAI virus on porous materials due to disinfection. The distributions for Lwash (Appendix 9 Figure 1) and Ldis(Appendix 9 Figure 2) were estimated from expert opinion utilizing the methods described in Appendix 7.2. The distribution for Lwash had a mean of 1 log EID50 (90 percent P.I. 0-2). The distribution for Ldis had a mean of 2 log EID50 (90 percent P.I. 0-2). Note that the distribution for Ldis is bimodal as a result of the considerable difference between both the experts’ opinions on this parameter. Appendix 9.1: Overall degree of HPAI virus inactivation on porous surfaces due to cleaning and disinfection The distribution for the degree of inactivation of HPAI virus on porous egg packing materials with washing and disinfection combined Ltotal was estimated as the convolution of the probability distributions of Lwash and Ldis i.e., Ltotal = Lwash+ Ldis.. The distribution for Ltotal was estimated through simulation with @RISK for 20,000 iterations with Latin Hypercube sampling (Appendix 9 Figure 3). The distribution for Ltotal had a mean of 3.45 log EID50 (90 percent P.I. 1.5-5.75). As shown in Appendix 9 figure 1, there is a 57 percent chance that more than 3-log EID50 inactivation of HPAI virus is achieved through washing and disinfection. In addition, there is a 13 percent chance of less than 2 log EID50 inactivation on porous surfaces with washing and disinfection.

- 112 -

Appendix 9 figure 1. Distribution for Ldis, the degree of inactivation of HPAI virus on porous egg packing materials with disinfection.

Mean = 2.088813

X <=4.21 95%

X <=0.55 5

%

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0 2 4 6

Log EID50 inactivation on wood via disinfection

Appendix 9 figure 2. Distribution for Lwash, the degree of inactivation of HPAI virus on porous egg packing materials with washing.

Mean = 1.36894

X <=2.22

95%

X <=0.49

5%

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.625 1.25 1.875 2.5

Log EID50 inactivation on wood via washing

- 113 -

Appendix 9 figure 3. Distribution for Ltotal, the degree of inactivation of HPAI virus on porous egg packing materials with washing and disinfection.

Mean = 3.457752

X <=3 42.565%

X <=2 13.305 %

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 2 4 6 8

Log EID50 inactivation via washing and disinfection

Appendix 9.2: Estimated number of porous materials from an infected but undetected farm that are contaminated with HPAI virus from egg contents In chapter 9, the surface viral titer on a 1mm layer of egg contents persisting on the materials after washing was estimated to be 103.5EID50/cm2 based on a pilot experiment. For this titer to be effectively inactivated (viral titer less than 0.5 EID50/cm2), the cleaning and disinfection procedures have to result in a 3-log EID50 inactivation of virus. From Appendix 9.1, the probability of having 3 or more log EID50 inactivation of HPAI virus on wood with cleaning and disinfection, Peff, was estimated as 0.574. The number of porous materials from an infected but undetected farm that are contaminated with HPAI virus from egg contents and not effectively inactivated Nineff was modeled as Nineff ~Binomial(Nhleak, (1- Peff)). The distribution for Nhleak, the number of HPAI contaminated leaking eggs was estimated in Appendix 8.1. We estimated the distribution for Nineff by simulating the Binomial (Nhleak, (1- Peff)) distribution with @RISK for 20,000 iterations with Latin hypercube sampling. The mean Nineff from the simulation results was 0.081(90 percent P.I 0-1).

- 114 -

Appendix 9.3: Likelihood of porous packing materials contaminated through the packing or storage room floors being effectively inactivated with cleaning and disinfection.

Let the viral titer on porous egg packing materials cross contaminated through the packing or egg storage room floor at the nest run farm be denoted by Cfloor. Scenario analysis from Appendix 12 indicated that Cfloor may range between 100.6 -102.9 EID50/cm2. We utilized a uniform (0.6-2.9) log EID50/cm2 as the uncertainty distribution for Cfloor. The residual viral titer on the porous egg packing materials cross contaminated through the egg storage room floor after cleaning and disinfection Ccd in units of log EID50/cm2, was calculated according to equation A9.1 below.

totalfloorcd LCC != (A9.1)

We estimated the distribution for Ccd by simulating equation A9.1 with @RISK for 20,000 iterations with Latin hypercube sampling. The mean Ccd from the simulation results was 1.70 (90 percent P.I 4.25-0.54) log EID50/cm2. Based upon the distribution for Ccd, there is a 95 percent chance that cleaning and disinfection will effectively inactivate (viral titer less than 0.5 log EID50/cm2) HPAI virus on porous egg materials contaminated from the packing room floors.

- 115 -

Appendix 10. 9CFR590 Section Contents and Electronic CFR Web Address

http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=b3f52a13c44bd404a523a877b481e90d&rgn=div5&view=text&node=9:2.0.2.5.47&idno=9

Title 9: Animals and Animal Products PART 590—INSPECTION OF EGGS AND EGG PRODUCTS (EGG PRODUCTS INSPECTION ACT)

Section Contents Definitions § 590.1 Meaning of words. § 590.5 Terms defined. Administration § 590.10 Authority. § 590.13 Federal and State cooperation. § 590.17 Nondiscrimination. § 590.18 OMB control numbers assigned pursuant to the Paperwork Reduction Act. Scope of Inspection § 590.20 Inspection in accordance with methods prescribed or approved. § 590.22 Basis of service. § 590.24 Egg products plants requiring continuous inspection. § 590.26 Egg products entering or prepared in official plants. § 590.28 Other inspections. Relation to Other Authorities § 590.30 At official plants. § 590.35 Eggs and egg products outside official plants. Eggs and Egg Products Not Intended for Human Food § 590.40 Continuous inspection not provided. § 590.45 Prohibition on eggs and egg products not intended for use as human food. Refrigeration of Shell Eggs § 590.50 Temperature and labeling requirements. Exemptions § 590.100 Specific exemptions. § 590.105 Suspension or termination of exemptions. Performance of Service

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§ 590.110 Licensed inspectors. § 590.112 Suspension of license or authority; revocation. § 590.114 Surrender of license. § 590.116 Activities of inspectors. § 590.118 Identification. § 590.119 Political activity. § 590.120 Financial interest of inspectors. § 590.122 Time of inspection. § 590.124 Schedule of operation of official plants. § 590.126 Overtime inspection service. § 590.128 Holiday inspection service. § 590.130 Basis of billing plants. § 590.132 Access to plants. § 590.134 Accessibility of product and cooler rooms. § 590.136 Facilities and equipment to be furnished by official plants for use of inspectors in performing service. Application for Service § 590.140 How application shall be made. § 590.142 Filing of application. § 590.144 Authority of applicant. § 590.146 Application for continuous inspection in official plants; approval. § 590.148 Order of service. Inauguration of Service § 590.150 Official plant numbers. § 590.155 Inauguration of service. Denial of Service § 590.160 Refusal, suspension, or withdrawal of service. § 590.161 Termination of plant approval. Records and Related Requirements for Eggs and Egg Products Handlers and Related Industries § 590.200 Records and related requirements. § 590.220 Information and assistance to be furnished to inspectors. Administrative Detention § 590.240 Detaining product. Appeal of an Inspection or Decision § 590.300 Who may request an appeal inspection or review of an inspector's decision. § 590.310 Where to file an appeal. § 590.320 How to file an appeal. § 590.330 When an application for an appeal inspection may be refused. § 590.340 Who shall perform the appeal.

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§ 590.350 Procedures for selecting appeal samples. § 590.360 Appeal inspection certificates. § 590.370 Cost of appeals. Certificates § 590.400 Form of certificates. § 590.402 Egg products inspection certificates. § 590.404 Erasures or alterations made on official certificates. § 590.406 Disposition of official certificates. Identifying and Marking Product § 590.410 Shell eggs and egg products required to be labeled. § 590.411 Requirement of formulas and approval of labels for use in official egg products plants. § 590.412 Form of official identification symbol and inspection mark. § 590.414 Products bearing the official inspection mark. § 590.415 Use of other official identification. § 590.417 Unauthorized use or disposition of approved labels. § 590.418 Supervision of marking and packaging. § 590.419 Reuse of containers bearing official identification prohibited. Inspection, Reinspection, Condemnation, and Retention § 590.420 Inspection. § 590.422 Condemnation. § 590.424 Reinspection. § 590.426 Retention. Entry of Material Into Official Egg Products Plants § 590.430 Limitation on entry of material. § 590.435 Wholesomeness and approval of materials. § 590.440 Processing ova. Sanitary, Processing, and Facility Requirements § 590.500 Plant requirements. § 590.502 Equipment and utensils; PCB-containing equipment. § 590.504 General operating procedures. § 590.506 Candling and transfer-room facilities and equipment. § 590.508 Candling and transfer-room operations. § 590.510 Classifications of shell eggs used in the processing of egg products. § 590.515 Egg cleaning operations. § 590.516 Sanitizing and drying of shell eggs prior to breaking. § 590.520 Breaking room facilities. § 590.522 Breaking room operations. § 590.530 Liquid egg cooling. § 590.532 Liquid egg holding. § 590.534 Freezing facilities.

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§ 590.536 Freezing operations. § 590.538 Defrosting facilities. § 590.539 Defrosting operations. § 590.540 Spray process drying facilities. § 590.542 Spray process drying operations. § 590.544 Spray process powder; definitions and requirements. § 590.546 Albumen flake process drying facilities. § 590.547 Albumen flake process drying operations. § 590.548 Drying, blending, packaging, and heat treatment rooms and facilities. § 590.549 Dried egg storage. § 590.550 Washing and sanitizing room or area facilities. § 590.552 Cleaning and sanitizing requirements. § 590.560 Health and hygiene of personnel. § 590.570 Pasteurization of liquid eggs. § 590.575 Heat treatment of dried whites. Laboratory § 590.580 Laboratory tests and analyses. Exempted Egg Products Plants § 590.600 Application for exemption. § 590.610 Criteria for exemption. § 590.620 Authority of applicant. § 590.630 Filing of application. § 590.640 Application for exemption; approval. § 590.650 Exempted plant registration number. § 590.660 Inspection of exempted plants. § 590.670 Termination of exemption. § 590.680 Approval of labeling for egg products processed in exempted egg products processing plants. Identification of Restricted Eggs or Egg Products Not Intended for Human Consumption § 590.800 Identification of restricted eggs. § 590.840 Identification of inedible, unwholesome, or adulterated egg products. § 590.860 Identification wording. Imports § 590.900 Requirements for importation of egg products or restricted eggs into the United States. § 590.905 Importation of restricted eggs or eggs containing more restricted eggs than permitted in the official standards for U.S. Consumer Grade B. § 590.910 Eligibility of foreign countries for importation of egg products into the United States. § 590.915 Foreign inspection certification required. § 590.920 Importer to make application for inspection of imported eggs and egg products. § 590.925 Inspection of imported egg products.

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§ 590.930 Imported egg products; retention in customs custody; delivery under bond; movement prior to inspection; sealing; handling; facilities, and assistance. § 590.935 Means of conveyance and equipment used in handling egg products to be maintained in sanitary condition. § 590.940 Marking of egg products offered for importation. § 590.945 Foreign egg products offered for importation; reporting of findings to customs; handling of products refused entry. § 590.950 Labeling of containers of eggs or egg products for importation. § 590.955 Labeling of shipping containers of eggs or egg products for importation. § 590.956 Relabeling of imported egg products. § 590.960 Small importations for consignee's personal use, display, or laboratory analysis. § 590.965 Returned U.S. inspected and marked products; not importations. § 590.970 Charges for storage, cartage, and labor with respect to products imported contrary to the Act.

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Appendix 11. Diagram of Egg Processing Plant

Shipping Dock

Receiving Cooler

Shipping Cooler

Source: Goble (1980)

Packaging Material Storage

ProcessingArea

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Appendix 12. Estimation of Viral Titers on Surfaces Contaminated from Floors of Nest Run Premises Background Information The movement of nest run eggs and egg packing materials gives rise to potential pathways for release and spread of HPAI virus that involve successive transfers of virus between contaminated and virus-free surfaces. For example, HPAI virus may be transferred to the egg storage area via shoes of personnel coming from the henhouse. Egg packing materials such as pallets, driver’s shoes and the vehicle floor may in turn get contaminated from the floor of the egg storage area. Given the lack of empirical data on the parameters associated with environmental contamination at HPAI infected nest run premises, precise quantitative evaluation of these pathways is challenging. Nevertheless, as a first step, scenario analysis based upon available surface transfer data for several different viruses and experimental soil track-in rates via shoes may be beneficial in understanding how various factors can impact the contamination through this pathway. In this appendix, we first summarize available data concerning the efficiency of virus transfer between contact surfaces for human and feline viruses. We then discuss the degree of contamination of certain environmental surfaces and fomites under two alternate scenarios. The first is the baseline scenario with the most likely values for the parameters. The second is a conservative scenario where we assume relatively cautious values for the parameters. For the purpose of this assessment, we define viral transfer efficiency between two surfaces as the ratio of the amount of virus transferred to a virus-free surface via direct contact, to the amount of virus present on the original contaminated surface. To date, data on the viral transfer efficiency between surfaces such as shoes to floors, floors to wooden pallets etc., are not available. However, numerous studies have been conducted on the transfer of human viruses from finger pads to inanimate surfaces and vice versa. In general these studies indicate that the viral transfer increases with the pressure applied, moisture content and friction during the contact. A summary of studies of viral transfer rates between surfaces is provided in Appendix 12 table 1. These data show that the viral transfer efficiency is mostly between 6-27 percent. However, it could be as high as 46 percent in some instances.

Appendix 12 Table 1. Summary of studies of viral transfer rates between surfaces.

Virus From To Percent transferred

Reference

Hepatitis A Fingerpads Lettuce 9.2 Bidawid et al, 200057 Feline Calicivirus Fingerpads Ham 46 Bidawid et al, 200410 Feline Calicivirus Fingerpads Lettuce 18 Bidawid et al, 200410 Feline Calicivirus Fingerpads Steel 13 Bidawid et al, 200410 Feline Calicivirus Ham Fingerpads 6 Bidawid et al, 200410 Feline Calicivirus Lettuce Fingerpads 14 Bidawid et al, 200410 Feline Calicivirus Steel Fingerpads 7 Bidawid et al, 200410

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Human Rotavirus Fingerpads Steel 16.1 Ansari et al, 198858 Human Rotavirus Steel Fingerpads 16.8 Ansari et al, 198858 Human Rotavirus Fingerpads Fingerpads 6.6 Ansari et al, 198858 Rhinovirus Steel Fingerpads 0.58 Sattar et al, 199329 Hepatitis A Steel Fingerpads 22 Mbithi et al, 199259 Hepatitis A Fingerpads Steel 27 Mbithi et al, 199259 Hepatitis A Fingerpads Fingerpads 23 Mbithi et al, 199259 Rhinovirus Fingerpads Steel 0.92 Ansari et al, 199160 Rhinovirus Steel Fingerpads 0.67 Ansari et al, 199160 Rhinovirus Fingerpads Fingerpads 0.71 Ansari et al, 199160 Human Parainfluenza Virus

Fingerpads Steel Undetectable Ansari et al, 199160

Human Parainfluenza Virus

Steel Fingerpads 1.48 Ansari et al, 199160

Human Parainfluenza Virus

Fingerpads Fingerpads Undetectable Ansari et al, 199160

Influenza A (H1N1)

Steel Fingerpads 0.01 - 8 Bean et al, 198211

Influenza A (H1N1)

Paper tissue Fingerpads 0.25 Bean et al, 198211

Model for estimating the viral titers of environmental surfaces and fomites without considering cleaning and disinfection The parameters of the model and the formulas used to calculate them are summarized in Appendix 12 table 2. This model considers that some amount Q of dust adheres to each shoe of personnel coming into egg packing areas from the henhouse. Only a fraction finf of the dust adhering to personnel shoes is assumed to be from infected areas of the henhouse. Simulation models of the active surveillance protocol show that HPAI infection would be detected before 0.5 (90 percent P.I. 0.016-2.6) percent of the flock is infectious. The viral titer of the dust settled on the passage floor near contaminated areas of the henhouse was obtained from section 8.2.3.2. The viral titer of each contact surface was calculated in successive steps as the product of the original viral titer on the contaminated surface and the viral transfer efficiency. For this model, we assumed the same viral transfer efficiency regardless of the specific surfaces involved in the transfer. Models for bacterial cross contamination have also utilized transfer efficiency or transfer rate in a similar manner (Perez Rodriguez et al., 2006)61. Another important assumption is that the viral titer in the contaminated portions of various surfaces is homogeneous.

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Appendix 12 Table 2. Description of the model parameters.

Parameter Description Symbol Formula

Viral transfer efficiency between contact surfaces η Input parameter Amount of virus contaminated material adhering per shoe (g/shoe)

Q Input parameter

Percent of dust from infected rows of the henhouse among the material adhering to shoes of the personnel

finf Input parameter

Surface area of a shoe (cm2/shoe) A Input parameter Viral titer of the dust accumulated on henhouse floor near infected hens (EID50/g)

H Input parameter

Surface viral titer of shoes of personnel entering egg packing area from henhouse at nest run farm (EID50/ cm2)

S1 HQfinf/ A

Surface viral titer of egg packing room floor at nest run premises contaminated via shoes of personnel(EID50/ cm2)

S2 ηHQfinf/ A

Surface viral titer of egg packing materials at nest run premises contaminated from the packing room floors (EID50/ cm2)

S3 η2 HQfinf/ A

Surface viral titer of trailer interior of the vehicle transporting nest run eggs contaminated via egg packing materials or shoes of personnel loading eggs (EID50/ cm2)

S4 η3 HQfinf/ A

Surface viral of the loading dock, forklift and connecting passages at processing center contaminated via egg packing materials from infected but undetected farm (EID50/ cm2)

S5 η3 HQfinf/ A

Surface viral titer egg packing materials cross contaminated from forklifts or contaminated floor areas at processing center (EID50/ cm2)

S6 η4 HQfinf/ A

Baseline scenario In the baseline scenario, we assumed the most likely values for the parameters. It was assumed that dust from a contaminated portion of the henhouse constituted at most 20 percent of the total dust adhering to a shoe. This estimate is fairly conservative given that the active surveillance model showed that HPAI infection in the flock would be detected before 2.6 percent of the flock is in an infectious state. The results from the baseline scenario show that there would probably be some moderate level of contamination of egg packing materials (less than 103 EID50/cm2) from the egg packing or cooler room floors at nest run premises. The viral titer through cross-contamination of materials from an uninfected farm via processing center floors or shipping docks is very low and inconsequential under this scenario.

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Appendix 12 Table 3. Parameter estimation for the baseline scenario.

Parameter Description Estimate Source/formula

Viral transfer efficiency between contact surfaces 0.16 Human virus data/(VS Springthorpe, pers. comm. March 2010).

Amount of virus contaminated material adhering per shoe (g/shoe)

2 Experimental soil shoe track in data from (Hunt et al. 200628)


0.2 Active surveillance simulation model

Surface area of a shoe (cm2/shoe) 250 Approximate, direct estimation

Viral titer of the dust accumulated on henhouse floor near infected hens (EID50/g)

100000 Section 8.2.3.2 in main document


160 HQfinf/ A


25.6 ηHQfinf/ A


4.096 η2 HQfinf/ A


0.65 η3 HQfinf/ A


0.65 η3 HQfinf/ A


0.10 η4 HQfinf/ A

Conservative Scenario (Cautious estimation of parameters) In this scenario, we used very cautious values for input parameters. Specifically, we assumed a value of 106 EID50 per gram of dust and a viral transfer efficiency of 40 percent (SA Sattar, pers. comm. March 2010). The results from this scenario (Appendix 12, Table 4) show that the level of contamination of egg packing materials from the egg packing or cooler room floors would be less than 103 EID50/cm2 even when cautious values for parameters are used. However, in this scenario there could be some residual cross-contamination of the materials from an uninfected farm through the processing center floors or shipping docks if they are not cleaned and disinfected (about 2 log EID50/cm2).

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Appendix 12 Table 4. Parameter estimation for conservative scenario.

Parameter Description Estimate Source/formula

Viral transfer efficiency between contact surfaces 0.4 Human virus data/(SA Sattar, pers. comm. March 2010).

Amount of virus contaminated material adhering per shoe (g/shoe)

3 Experimental soil shoe track in data from (Hunt et al 2006)


0.4 Active surveillance simulation model

Surface area of a shoe (cm2/shoe) 250 Approximate, direct estimation

Viral titer of the dust accumulated on henhouse floor near infected hens (EID50/g)

1000000 Section 8.2.3.2 in main document


4800 HQfinf/ A


1920 ηHQfinf/ A


768 η2 HQfinf/ A


307.2 η3 HQfinf/ A


307.2 η3 HQfinf/ A


122.88 η4 HQfinf/ A

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Appendix 13. The Use of “Negligible Risk” in this Assessment Negligible Risk Defined for this Analysis: For this risk analysis, the term “negligible risk” means there is a very low likelihood that specific risk pathway being evaluated will cause infection in another poultry production premises. In quantitative terms, this is defined as the likelihood of less than 1/1,000,000 that the risk pathway will result in infection in other premises. This particular likelihood is used to be consistent with other common meanings for the term, as discussed below. The determination of “negligible risk” suggests that allocating additional resources to mitigate this risk may not be a cost-effective use of resources (depending on circumstances). Negligible Risk as Less Than 1/1,000,000 Origins Use of the term “negligible risk” originated in efforts to regulate chemical exposures. While there is no formal definition, the term evolved in the human exposure risk assessment literature as a lifetime cancer risk of less than 1/1,000,000. This particular level was selected as it was thought to be a level of “essentially zero” risk. 62-66While this level has not been formally defined in legislation, The House Committee on Commerce evaluated the use of this term by the Environmental Protection Agency, and agreed that the agency’s interpretation of the term “negligible risk” to be approximately a one-in-a-million lifetime risk as appropriate.67 Use in Agricultural Risk Analysis The use of risk analysis for imports of agricultural products became mandatory with the adoption of the SPS Agreementu in 1995.v Specific recommendations and standards were to be established by the appropriate technical body. For animals and animal products, this is the Office International des Epizooties (OIE, or World Organization for Animal Health).68 The OIE has published standards and guidance for conducting risk analysis, but has not formally defined “negligible” in a quantitative sense. 69-71 However, in a World Trade Organization trade dispute case,72 negligible risk was considered to be a risk whose probability is very low,73 or, as an expert consultant to the WTO Dispute Panel put it, “the standard scientific definition of "negligible" was a likelihood of between zero and one in one million.”74 Policy Implications of a Quantitative Definition for Negligible While the 1/1,000,000 definition for negligible risk has substantial precedence (as shown above), there are difficulties with this approach. The 1/1,000,000 likelihood has been described as “folklore,”75 vague and inconsistent,66 and has been “used and (abused) in various policy contexts.”76 However, use of this figure is meant to be a very rough approximation and should not be given the same degree of certainty that may be applied when quantitative risk assessments can be used. u Formally known as the “Agreement on the Application of Sanitary and Phytosanitary Measures (SPS) and Agreement on Technical Barriers to Trade (TBT).” v Risk analysis is also required for moving animals and animal products during an HPAI oubreak.79

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Negligible Risk as a Qualitative Measure for Agricultural Risk Analysis The OIE has issued guidance that recommends using ”negligible” to mean “not worth considering; insignificant.”69 The use of qualitative risk analysis methods by APHIS and the implied non-requirement for attaching a specific number to a level of risk has been challenged in the U.S. Court system and has been upheld as appropriate, if the analysis presents adequate scientific information.77 When used in this manner, the courts have held that the determination of risk may be based on “the cumulative effects of the multiple, overlapping, safeguards.” Furthermore, the courts have held that an “imposition of such a bright-line prohibition on qualitative standards was incorrect,” and that the Animal Health Protection Act does not require a quantified permissible level of risk.78 These opinions by the court system are also consistent with U.S. views expressed in WTO trade disputes.

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Appendix 14. The Use of “Low Risk” in this Assessment Low risk For this risk analysis, the term “low risk” means it is highly unlikely that moving nest run eggs will cause infection in another poultry production premises. The determination of “low risk” suggests that although not a strict requirement, additional resources to further evaluate or mitigate this risk may be considered (depending on circumstances). Use in risk analysis The term “low risk” has been frequently used in risk rating systems for qualitative risk analysis. These risk rating systems are often customized according to the specific objectives of the risk assessments. Consequently, there is a significant variation in the interpretation of the terms used to describe risk among various risk assessments. For example, in USDA APHIS guidelines on pathway initiated pest risk assessment, the rating of low is interpreted as “the pest will typically not require specific mitigations measures”. The FDA guidance document 152 states “For a drug to be ranked as low risk overall, two of three major components (release, exposure and consequence) of the risk assessment should be ranked as low and the third component ranked as moderate”. In a risk rating system used in USDA APHIS template for qualitative risk assessment for potential federal noxious weeds, the overall pest risk potential is low as long as the likelihood of introduction of the weed is low regardless of the consequences of introduction. Overall, various definitions of “low risk” have been utilized as appropriate in different situations. Low risk vs. Negligible risk. There are two related reasons for rating a risk as low vs. negligible. The first is that the risk assessment determined that the level of risk is not negligible and hence additional mitigation measures may be considered in some cases. A second reason is that due to the uncertainty in the risk estimate, it is not clear whether the risk is low or negligible. This uncertainty can be expressed as probability distribution for the risk in a fully quantitative risk assessment. For qualitative risk assessment, there are no formal means of expressing this uncertainty. Therefore, when there is uncertainty about whether the risk is low or negligible, we conservatively rate it as “low risk”. In this case, depending on the circumstances, additional mitigation measures or further evaluation to reduce the uncertainty may be considered.

an assessment of the risk associated ... - secure egg supply

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