outcomes analysis of e. coli o157:h7 vaccination in beef cattle

Outcomes Analysis of E. coli O157:H7 Vaccination in Beef Cattle

H. Scott Hurd College of Veterinary Medicine, Department of Production Animal

Medicine

Former Deputy Undersecretary of Food Safety, USDA

Director of World Health Organization Collaborating Center for Risk Analysis and Hazard Surveillance and Intervention in Food

Animals

Co-Director Collaboration for Comparative Outcomes Research Evaluation (CCORE), Iowa State University, Ames IA 50011

[email protected]

mailto:[email protected]

2

Overview of Today’s Topics

Why Does the Industry Worry About E. coli O157:H7?

Pre-harvest Interventions Work Sometimes,But Not Other Times

E. coli 0157:H7 Vaccination is One of Those Times That Works


3

E coli O157:H7 has a litter

4

Pre-harvest Interventions Work Sometimes

● The pathogen originates solely on the farm

● Food animal is the primary host

● Pathogen does not live well outside the host

● The % of positive farms is relatively low

● Post-harvest methods are “maxed-out”

● Dealing with outlier events

5

Control of Salmonella in Denmark – 10 Years Experience – Preharvest Not Most Effective

● Hurd HS, Enøe C, Sørensen L, Wachmann H, Corns SM, Bryden KM, Greiner M: Risk-based analysis of the Danish pork Salmonella program past and future. Risk Analysis. 28:2 pp 341-351, 2008

● Funded as a project of the International EpiLab

– Danish Institute for Food and Veterinary Research (DFVF)

– Guest Scientist at the EpiLab in Denmark,

– Employed at the National Animal Disease Center:USDA:ARS, Ames, Iowa, USA

6

Systems Model (Simulation) of Pork Attributable Human Cases (PAHC) of Salmonellosis

Probability of Carcass Swab

Positive Given Herd Seroprevalence

Category

Distribution of Herds By

Seroprevalence Category and Size

Attributes Human Cases as a

Function of Positive Carcasses

ProductionModule

Slaughter module

AttributionModule

Pigs from Each Seroprevalence

Category

Carcass Swab Positive Pigs

Human Cases per Year

7

Historical: Combined Effect of On-farm (Pre-harvest) Changes and Abattoir (Post-harvest)

Simulated Pork Attributable Human Cases (Total Cases)

1995 1996 1997 1998 1999 2000 2001 2002 20030

50

100

150

200

250

300

350

400

450

Lower Historical Historical – Farm & AbattoirUpper Historical

Significant (P <0.05) Changes in Risk

Occurred 1998–2000

8

Switch off the Post-harvest see Effect of On-farm (Pre-harvest) Program Only


1995 1996 1997 1998 1999 2000 2001 2002 20030

50

100

150

200

250

300

350

400

450

Lower Historical Historical – Farm & AbattoirUpper Historical Abattoir95

Only 19% Decrease,69 Cases (P>0.05)

9

Switch off the Pre-harvest Program see Abattoir (Post-harvest) Improvements Only


1995 1996 1997 1998 1999 2000 2001 2002 20030

50

100

150

200

250

300

350

400

450

Lower Historical Historical – Farm & AbattoirUpper Historical Farm 1995

A Difference of 81 Cases (P>0.05). Due to Abattoir

Improvements Only

10

Future: Major Reduction in on-farm Seroprevalence (<25% for all herds)

Distribution of Herds by Average Annual Seroprevalence

0 5 15 25 35 45 55 65 75 85 950%

10%

20%

30%

40%

50%

2004

2006

2008

2010

2012

Seroprevalence Group

Pe

rce

nta

ge

Year

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014100

110

120

130

140

150

160

170

180

AllFarm25 RevF ImpF

Future: Reduce All Herds to <25% Average Annual Seroprevalence

Cases While Steadily Improving Abattoir Methods for All On-farm Values Set at 25% or Less (AllFarm25); Reverting On-farm to 1995 Values While Keeping Abattoir Values Constant (RevF);

and Continuing to Improve On-farm While Keeping Abattoir Values Constant (ImpF)

11

Attributable Human Cases

Still End Up with 110

Cases/Year

What Else Can Be Done?Carcass Decontamination (Post-harvest)

Number of Pork Attributable Human Cases

Percentage of the National Herd Decontaminated

Equivalent Annual

Seroprevalence Cut-off

Lower Mean Upper

0% NA 136 152 168

1.50% Level 3, >45% 131 147 163

10.00% >25% 110 126 142

100.00% All 14 15 16

12

13


● The pathogen originates solely on the farm

● Food animal is the primary host

● Pathogen does not live well outside the host

● The % of positive farms is relatively low

● Post-harvest methods are “maxed-out”

● Dealing with outlier events


Post-harvest Methods Are “Maxed-out”

● Further reduction of the mean exhausted

● Law of diminishing returns

Dealing with Outlier Events

14

We Have MANY Post-harvest Processes in Place Which “On Average” Work Well

15

Pre-harvest Methods “Maxed Out” – Law of Diminishing Returns

● Or “half the distance to the goal line”

● Diminishing utility = “meaning that the first unit of consumption of a good or service yields more utility than the second and subsequent units” (Wikipedia)

16

6% 7% 8% 9% 10% 11% 12% 13% 14% 15% 16% 17% 18% 19% 20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

Prevalence

Pro

ba

bili

ty

17

Outlier Events – Why Do They Happen?

“On Average”

● Prevalence and concentration of E. coli in cattle is not abell curve

● It is Poisson distributed

● Average is low

● Occasional HIGH levels

Poisson Probability Distribution

6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

18

When Multiple ProcessesAre Poisson Distributed

Cattle Prevalence Carcass Prevalence Concentration

Event Day

Cut-off the First Tail and Subsequent Ones Not as Likely to Occur

19


6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

20

Overview of Today’s Topics




Thomson DU, Loneragen GH, Thornton AB, et al., Use of a Siderophore Receptor and Porin Proteins-Based Vaccine to Control the Burden of Eschericia coli O157:H7 in Feedlot Cattle. Foodborne Pathogens and Disease 2009; Vol. 6, Number 7, 871-877 21

E. coli Bacterial Extract Vaccine: Results

d0 d42 d980

5

10

15

20

25

30

Vaccinates Placebo

E. c

oli

0157

Pre

vale

nce

85% reduction in shedding



d0 d42 d980

5

10

15

20

25

30

Vaccinates Placebo

E. c

oli

0157

Pre

vale

nce

Concentration on d980

1

2

3

4

0.90

2.53

Lo

g10

MP

N/g85% reduction in

shedding

98% reduction in concentration

23

Consistent significant impact of vaccination on E. coli prevalence

● Every study to date has yielded a significant reduction in E. coli shedding

Reductions from 50-85% based on protocols and E. coli challenge

Best Available Data

24

Mathematical Model “Converts” 0157:H7 Shedding Cattle to Human Illnesses

Production Slaughter Consumption

25

How Does Vaccine Help ReduceEvent Days? -Individual Carcasses Modeled

Modeling of Individual Carcasses in a Production Lot Carcass 1 Carcass 2… ..Carcass 68

S14The E. coli O157:H7 average surface

concentration on a pre-evisceration carcass of unvaccinated cattle (CFU per 100 cm2)

1.5 1.5 0.9375

S15The surface area contaminated with E. coli

O157:H7 per contaminated carcass (cm2/carcass)

8000 8000 8000

S16 Total CFU of E. coli O157:H7 on a carcass at pre-evisceration step (CFU/carcass) 120 120 75

S17 Log reduction of E. coli O157:H7 concentration due to decontamination 0.88 0.90 2.33

S18Total CFU of E. coli O157:H7 on a

contaminated carcass after antimicrobial intervention (CFU/carcass)

15.94 14.97 0.35

S19

CFU of E. coli O157:H7 added to a 10,000 pound production lot of trim from a

contaminated carcass fromunvaccinated feedlot

11.16 10.48 0.25

S20_vCFU of E. coli O157:H7 added to a 10,000

pound production lot for a contaminated carcass of vaccinated cattle

1.40 1.32 0.03

Scenarios Evaluated

Additionally, Simulated for Various Levels of Product Adoption by Producers 0%, 40%, 80%, 100%

Details of the Scenarios for the Impact of Vaccination on Prevalence and Concentration of E. coli 0157:H7 in Cattle Feces

Scenario Percentage Reduction in Feedlot

Log10 CFU/g Reduction in Average E. coli

0157:H7

A 80 1.0

B 60 0.3

C 40 0.3

26

Four Outcome Measures Considered

Mean annual number of human E. coli O157:H7 illnesses due to consumption of ground beef from steers and heifers (Public Health)

1

Probability of detecting E. coli O157:H7 per ground beef or ground beef trim sample tested by FSIS (in a 10,000 lb lot) (Regulatory)

2

Mean annual number of events where multiple E. coli 0157:H7 human illnesses (outbreaks) occur due to consumption of ground beef from a single production lot (Outbreak)

3

Mean annual number of a “hot” production lots (hot lot = more than 1,000 E. coli O157:H7 contaminated ground beef servings from a single lot) (Event Days)

4

27

28

Outcome. Annual Number ofE. coli O157:H7 Illnesses

Annual 0157 Illnesses by Efficacy an Adoption

0% 40% 80% 100%0

5,000

10,000

15,000

20,000

25,000 Efficacy 80%

Efficacy 60%

Efficacy 40%

Vaccine Adoption

Nu

mb

er

of

Illn

es

se

s

Discussion of Results –Annual Number of Illnesses

● If vaccine is 80% effective and used by all producers, the projected number of cases is reduced from 20,000 to 8,000 (60% decrease)

● However, partial adoption is also useful

– 80% effective with 40% adoption 23% reduction in illness

– 60% effective with 80% adoption 36% reduction in illness

29

Outcome. Annual E. coli O157:H7 Illnesses Decreases with Adoption

30

Number of E. coli 0157:h7 Illnesses Due to Consumptionof Ground Beef from Feedlot Cattle

0% 40% 80% 100%0

5,000

10,000

15,000

20,000

25,000Efficacy 80%

Efficacy 60%

Efficacy 40%

Vaccine Adoption

Nu

mb

er

of

Illn

es

se

s


● National public health utility is largely a function of adoption, not vaccine efficacy

● If 40% effective and 100% adoption there will be 40% reduction in illnesses

31

Impact on Illness Due to Reduced Cattle Prevalence and Concentration on Carcass

32

Distribution of Herds by Average Annual Seroprevalence

0

0.3

0.6

0.9

05,000

10,00015,00020,000

0.3

0.45

0.6

0.8

Fraction Reduction in Prevalence

Log CFU/g Reduction in Concentration of E. coli 0157:

H7 in Feces

Nu

mb

er

of

Hu

ma

n C

as

es


● Illness is impacted by BOTH decreased concentration and frequency of positive carcasses (prevalence)

● Most Post-harvest methods just reduce concentration

– Evaluated by “log reduction”

33

34

Outcome. Probability of Detection viaFSIS Sampling (Regulatory)

● Assumed FSIS testing of raw ground beef detects 1 CFUin a 325 g sample

● Based on average probability of detection per sample tested for different slaughter plants and for different production lots from the same plant

● Impact of additional industry test and hold is not considered

35

Outcome. Detection by FSIS

Probability of Regulatory Positive by Efficacy and Adoption

0% 40% 80% 100%0.000%

0.050%

0.100%

0.150%

0.200%

0.250%

0.300%

0.350%

0.400% Efficacy 80%

Efficacy 60%

Efficacy 40%

Vaccine Adoption

Pro

ba

bili

ty o

f D

ete

cti

on

by

FS

IS

36

Outcome. Outbreaks

● Number of lots resulting in outbreak defined as:

– >2 illnesses

– 5 illnesses, or

– 10 illnesses

● From a single production lot

● Assuming 100% vaccination of cattle

● Typical large plant (16,000 lots/yr)

37

Number of Lots Resulting in >2, 5,or 10 Illnesses (Assuming 100% of Herds Vaccinated)

2 5 100

10

20

30

40

50

60

70

80 No Vaccine

Efficacy 80%

Efficacy 60%

Efficacy 40%

Number Cases in a Defined Outbreak

Mean Number of Lots per Year Resulting in Multiple Illnesses

Vaccination (100% Herds), Virtually Eliminates

Chance of a Large >10 Case Outbreak

38

Outcome. “Hot” Production Lots

● There is a high degree of variance in the E. coli O157:H7 numbers/concentration in a production lot

● Consequently a small fraction of production lots may be contaminated to a high degree (“hot” lots), although the average load per production lot is relatively small

● We defined a production lot (10,000 lbs) containing more than 1,000 contaminated servings as “hot” lot

● Results are for hypothetical slaughter establishment producing 16,000 production lots per year

39

Prevalence and ConcentrationAre NOT Normally Distributed

● Prevalence and concentration of E. coli in cattle is not abell curve

● It is Poisson distributed

● Occasional HIGH levels

6% 7% 8% 9% 10% 11% 12% 13% 14% 15% 16% 17% 18% 19% 20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

Prevalence

Pro

ba

bili

ty

Poisson Distribution of E. coli Prevalences

40

Outcome. Hot Lots for a Plant Producing 16,000 Production Lots Per Year

Annual Number Hot Lots for Large Plant by Efficacy and Adoption

0% 40% 80% 100%0

20

40

60

80

100

120

140

160Efficacy 80%

Efficacy 60%

Efficacy 40%

Vaccine Adoption

Nu

mb

er

Pe

r Y

ea

r

41

Outcome. Hot Lots for a Plant Producing 16,000 Production Lots Per Year

Annual Number Hot Lots for Large Plant by Efficacy and Adoption

0% 40% 80% 100%0

20

40

60

80

100

120

140

160 Efficacy 80%

Efficacy 60%

Efficacy 40%

Vaccine Adoption

Nu

mb

er

Pe

r Y

ea

r

42

Discussion of Results – Hot Lots

● All levels of efficacy and adoption reduce the risk to packer

● Full adoption of 80% effective vaccine virtually eliminates chance of Hot Lots (96% reduction)

● 40% adoption of an 80% effective vaccine results in 43% reduction in probability of Hot Lots

● 80% adoption of 60% effective vaccine results in 49% reduction in probability of detection by FSIS

● What is a 20%, 30%, 40% reduction in risk worth?

43

Annual Hot Lots – Vaccine Reduces Variation and Extreme Doses

0 20 40 60 80 100 120 140 160 180 200

Hot Lots Vac-cinated – 40%

Scenario

Hot Lots Unvacci-

nated

Box-Whisker Plot Comparison

More Variation and More

“Event Days”

44

Impact of Vaccination on Number of ProductionLots with High E. coli 0157 Prevalence (>5%)in 325 Gram Samples

5.00

%

28.75%

52.50%

76.25%

100.00

%

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.075.0% 76.3%

Unvacc

Vac 60%

E. coli 0157 Prevalence in 325 Ground Beef Portions from the Production Lot

45

How Does Vaccine Help ReduceEvent Days, Hot Lots

6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16


Event Day

Cut-off the First Tail and Subsequent Ones Not as Likely to Occur

46


6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

6%

7%

8%

9%

10%

11%

12%

13%

14%

15%

16%

17%

18%

19%

20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

47

Vaccination Reduces Variation = Risk

● The overall average prevalence of O157:H7 in cattle and ground beef is low

● Occasional “event days” or “hot lots” drive the risk

● Small fraction of carcasses are highly contaminated

● Vaccination has a disproportionate impact on thesetail-end events, reducing frequency of high prevalence cattle and high concentration of bacteria

48

Summary

● Analysis included impact of biological variation and uncertainty in parameters

● Modeled from “farm to fork” using best available scientific data

● Showed that vaccination reduces

– Human 0157:H7 cases

– Risk of FSIS regulatory detection

– Chance of large outbreak from a lot

– Frequency and magnitude of “event days”

49

Questions




Appendix A

Materials & Methods

51

Materials and Methods

● Stochastic simulation model using a farm to fork approach (Excel®, @Risk®)

– Stochastic – pick numbers randomly from defined distribution

● Impact of E. coli O157:H7 vaccination in reducing the prevalence (% fecal positive cattle) and concentration (log CFU in trim) modeled

● Consists of three modules

– Production

– Slaughter

– Consumption

52

Mathematical Model “Converts” 0157:H7 Shedding Cattle to Human Illnesses(Best Available Data)


53

What is a “Stochastic Simulation”?

● Exact cattle prevalence and other variables are unknown and changing

● Studies give a range and statistical distribution which is often non-normal (Poisson)

● Computer uses all those possible numbers to calculate multiple results (n=10,000)

Probability of Various E. coliPrevalence Occurrences

6% 7% 8% 9% 10% 11% 12% 13% 14% 15% 16% 17% 18% 19% 20%-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

Prevalence

Pro

ba

bili

ty

54

Slaughter Module – Individual Carcass Modeled




1.5 1.5 0.9375



8000 8000 8000





15.94 14.97 0.35

S19



11.16 10.48 0.25



1.40 1.32 0.03

Stochastic Variables

55

Modeling Assumptions

● The E. coli O157:H7 prevalence in pre-evisceration beef carcasses is proportional to the fecal prevalence in the feedlot

● All beef imported (~40%) into the US is destined for mixing withdomestic ground beef

● The E. coli O157:H7 prevalence and concentration in imported ground beef is similar to that in ground beef from unvaccinated domestic steerand heifer slaughter

● The ground beef processed in this US is consumed domestically

● The number (CFU/serving or CFU/325g sample) of E. coli O157:H7 in a portion of ground beef from a production lot is Poisson distributed

● The impact of internal test-and-hold protocols is not considered

● The FSIS ground beef test data are assumed to be from a representative random sample of ground beef production lots in the US

56

Production Module


Estimates the E. coli O157:H7 Prevalence in Vaccinated and Unvaccinated Feedlots

● Prevalence among feedlots and within feedlots estimated.

● Vaccination reduces prevalence by fixed percent on average. Multiple different efficacy scenarios can be run

● Variability in feedlot prevalence and impact of vaccination modeled stochastically by exponential and binomial distributions

57

Scenarios Built Around Reductions in Prevalence and E. coli Concentration

Additionally, Simulated for Various Levels of Product Adoption from 0% to 100%

Scenario Percentage Reduction in Feedlot

Log 10 CFU/g Reduction in Average

E. coli O157:H7

A 80 1.0

B 60 0.3

C 40 0.3

58

Slaughter Module – Carcass Prevalence

FecalPrevalence (from

Production Module)

Pre-evisceration Carcass Prevalence

Post Chill Carcass Prevalence

Number Contaminated Carcasses per Production Lot

Linear Coefficient (Elders 2000, Barkocy-Gallagher 2003 and

Arthur 2007)

Effectiveness of Generic Post Slaughter Interventions (Elders et al. 2000,

Arthur et al. 2004 and Barkocy Gallagher et al. 2003)

Modeled as a Binomial Distribution

59

Slaughter Module – Bacterial Concentration

Concentration on a Pre-evisceration

Carcass

Total CFU/Carcass at Pre-evisceration

Total CFU/Carcass at Post Chill

Total CFU per Production Lot

Contaminated Surface Area (8000 cm2/Carcass)

Effectiveness of Post Slaughter Interventions Estimated from Generic

E. coli and APC Data

The Amount (CFU) Added to the Production Lot from Individual

Carcasses Was Summed Up. Assumed 70 Percent of Carcass Surface Area

Represented in Trim

60

Slaughter Module –Individual Carcasses Modeled




1.5 1.5 0.9375



8000 8000 8000





15.94 14.97 0.35

S19



11.16 10.48 0.25



1.40 1.32 0.03

61

Slaughter Module

● Estimates the prevalence and concentration of E. coli O157:H7 in beef carcasses and ground beef production lots

● About 68 Simulated carcasses for a 10,000 pound production lot, depends on average carcass weight

● Variable E. coli O157:H7 concentrations on contaminated carcasses were modeled


62

Total Carcass Contamination a Function of Fecal Shedding, Amount of Bacteria and Surface Area

63

Slaughter Module – Lot Types

Production Lot from Unvaccinated Cattle

● Includes ground beef trim from domestic and imported sources

● E. coli O157:H7 prevalence and concentration in ground beef from domestic and imported sources assumed to be similar

Production Lot from “Vaccinated” Cattle

● Domestic portion of ground beef in the lot is from vaccinated cattle

● Imported ground beef is assumed to be from unvaccinated cattle

64

Consumption Module

● Estimates overall number of E. coli O157:H7 illnesses due to consumption of ground beef from steers and heifers

● Fraction of E. coli O157:H7 illnesses attributed to ground beef consumption estimated from outbreak and epidemiological studies

● Similar to the approach used Withee et al., 2009


65

Consumption Module Attribution Calculation

Number of E. coli O157:H7

Contaminated Servings /Year

Domestic Cattle Slaughter and Beef

Import Data

FSIS Ground Beef Testing Data

CDC Foodnet DataAdjusted for Under

Diagnosis

Fraction of Illnesses Attributed to Ground Beef Consumption

Number of Illnesses from Ground Beef

per Year

Baseline Probability of Illness per

Contaminated Serving of Ground Beef

66

Consumption Module

● Outputs – mean number of E. coli O157:H7 illnesses per year in the US due to consumption of ground beef from steers and heifers calculated from:

Variables

● Baseline probability of E. coli O157:H7 illness per contaminated serving of ground beef consumed

● Estimated number of contaminated servings per production lot

● Estimated number of production lots from vaccinated and unvaccinated cattle processed

67

Methods Review

● Stochastic simulation model to evaluate the impact of O157:H7 vaccination on key epidemiologicaloutcome measures

● Considered a reduction in the O157:H7 prevalence as well as concentration in cattle feces due to vaccination

● Impact of this reduction on various risk outcomes was evaluated by simulating the relationships between the O157:H7 prevalence and concentration at various points in the ground beef supply chain

● The uncertainty and variability associated with the O157:H7 contamination was explicitly modeled on a carcass-by-carcass basis

68

Methods Review

● Included the impact of post harvest interventions, stochastically

● Combined best available scientific data about the processes to produce ground beef

● Shows the impact of true biological variation on the prevalence and concentration of E coli before and after each process

Appendix B

Reference Slides

* Total does not add to 100% due to rounding.Source: 2009 Food & Health Survey, International food Information Council Foundation. 70

Consumers Firmly Place Food Safety Responsibility on the Production Chain

In general, who do you believe is responsible for food safety in the U.S.?Select all that apply.

What, in your opinion, is the most important food safety issue today? Select one.

52%

30%

10% 6%

Foodborne Illnesses from Bacteria

Chemicals in Food

Imported Foods

Food Allergens 2%

Other 2%

Don’t Know

Perceived Responsibility for the Safety of theU.S. Food Supply

2009 (n=1064)

Perceived Importance ofFood Safety Issues

2009 (n=1064)*

More Than Half the Food Safety Concerns Expressed by ConsumersResides with Illnesses Stemming from Bacteria

Consumers/Individuals

Retailers/Food Service

Farmers/Producers

Government

Food Manufacturers

41%

49%

57%

72%

73%

How Concerned Are You About Foodborne Illnesses from Eating Ground Beef?

Source: National Cattlemen’s Beef Association – Consumer Perceptions of Beef Safety – October 2010Source: IPSOS Public Affairs – July 2010 71

Bacterial Contamination is aGrowing Concern for Consumers

Q: On a Scale of One to Five with One Being No Concern and Five Being Extremely Concerned, How Concerned Are You About…

Bact

eria

Pest

icid

esM

ad C

owD

isea

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hem

ical

Addi

tives

Hor

mon

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tibio

tics

GM

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Food

s

Concern about foodborne illness fromeating ground beef has increasedsignificantly since 2008

Bacteria in food currently is the number one rated food safety issue for consumers and has been the leading issue of concern for the past several years

Looking back over the past 10 years, bacterial concerns have been higher than all other issues except mad cow disease which was the issue of highest concern from 2002 until 2009

In 2001, 39 percent of consumers said they were extremely concerned about bacteria while a quarter (24%) said they were not concerned

In July 2010, 40 percent say they are extremely concerned about bacteria and only 7 percent say they are unconcerned

Consumer Food Safety Concerns% Rating a 5 (Extremely Concerned) on a 5-Point Scale

2008 20100%

20%

40%

60%Low ConcernHigh Concern

40%34% 34% 32% 29%

25% 26%22%

99%

98%

97%

93%

100%

Level of Concern Towards Issue(Base: Those Aware of Issue)

Source: Pfizer, Consumer Marketing Research 2010, Data on File.Q: Listed below are some food safety concerns people may have expressed when buying or eating beef. Using the scale below, please tell us how concerned you are, if at all, with each of these issues when buying or eating beef. 72

Safety Concerns with Regard to Eating Beef

Base: Total Respondents (N=1,029)

Extremely Concerned Extremely/Very/Somewhat Concerned

Beef consumers tend to be more concerned about E. coli than any other well-known beef pathogen. Just over one in four are extremely concerned with E. coli when eating and buying beef, and three in four express at least some level of concern

% Aware of Issue

Mad Cow Disease (n=1,029)

Botulism in Beef (n=970)

Salmonella in Beef (n=1,006)

E. coli in Beef (n=1,018)

Spoilage in Beef (n=1,025)

19%

20%

21%

27%

27%

49%

57%

64%

75%

82%

1 Schroeder T., Agricultural Economists, Kansas State University, in National Cattlemen’s Beef Association. A basic look at E. coli O157, 2004

2 Kay S., editor/publisher of Cattle Buyers Weekly (www.cattlebuyersweekly.com), in National Cattlemen’s Beef Association.A basic look at E. coli O157, 2004 73

E. coli O157 Costs Duringthe Past 10 Years

Category Costs2

Impact on Demand $1,584,000,000

Impact on Boneless Beef Prices $172,000,000

Capital Expenditure by Top 10 Packers $400,000,000

Increased Operating Costs for Top 10 Beef Packers $250,000,000

Spending by Next 20 Beef Packers $100,000,000

Recall Costs Incurred by Packers $100,000,000

Government and Industry Research $65,000,000

Total $2,671,000,000

Research has shown that beef-product recalls following outbreaks have a negative effect on demand for beef.For instance, boneless beef prices declined an average of 2.5% in the 5 days following one recall. From 1991 through 1999, beef recalls due to safety concerns were estimated to cost the industry as much as $1.6 billion in lost demand1

Producers have invested $20 million in check-off funds during the last decade in beef safety research while the top 10 beef packing companies spent $400 million on beef safety research. Packers have also incurred an estimated $250 million in increased operating costs due to changes at processing plants aimed at improving beef safety. Government and industry have spent at least $65 million since 1993 on E. coli O157 research, with the USDA Agricultural Research Service spending $49 million from 1993 to 2002 to research food safety

741 BeaconMR, March 2010

● Original mission: to solve a turkey salmonella problem, to improve poultry quality and food safety

● Key discoveries by WPC staff microbiologists led to numerous patents for a novel vaccine technology

● SRP® technology has great potential for multiple veterinary and human medical applications

Salmonella-SRP vaccine for cattle conditionally licensed in 2004

Approximately 5M doses used in US dairy industry annually in 2008 and 20091

Source: Emery, D.A. – “SRP Technology” presentation; Midwest Poultry Federation annual meeting, St. Paul, MN - March, 2002 75

State of Minnesota – Official Salmonella Test Results for Willmar Poultry Company Breeder Flocks

Percent Positive Flocks

Implementation of Salmonella SRP® Vaccination Over a

Two-Year Period

10,000 hens per flock500 cloacal samples/flock

50 flocks per year25,000 hens tested annually

1996 1997 1998 1999 2000 2001

94%83%

50%

27%20%

9%

76

E. coli O157:H7

● May 2010, USDA/FSIS announces

– “Pre-harvest Management Controls and Intervention Options for Reducing Escherichia coli O157:H7 Shedding in Cattle”

● FSIS Guidance notes:

– Establishments required to conduct hazard analysis that can occur before, during and after entry into establishment

– Fecal shedding is a hazard

– FSIS recommends slaughter establishments receive cattle that implement one or more documented pre-harvest management practices to reduce fecal shedding

77

Why Vaccines at Pre-harvest

These product licenses are conditional. Efficacy and potency test studies are in progress

● Vaccines enable a natural ally: the animal’s immune system

● Addressing the problem pre-harvest should allow processing interventions to be more effective

– Incoming pathogen burden can overwhelm in-plant processes

78

SRP Technology

● Pathogenic Gram-negative bacteria, including E. coli O157:H7 and Salmonella, require iron to liveand replicate

● SRP vaccines target the proteins necessary to transport iron into the bacterial cell, using the animals’ immune system to block iron passage

● As a result, without iron, the bacteria die

P<0.0001 Data on file, Epitopix LLC Study Report No. 0606, Pfizer Inc. 79

Reduced Number of Salmonella Newport Infected Animals

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 280%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

110%

Placebo Vaccine

28 Samplings Post-Challenge (AM/PM for 14 days)

Pe

rce

nt

Po

sit

ive

Cu

ltu

res

75% fewer infected animals 14 days post-challenge

Percent Positive for Salmonella Newport Infection Following Challenge

P<0.0001 Data on file, Epitopix LLC Study Report No. 0606, Pfizer Inc. 80

Quantity of Salmonella Shedding in Feces: Average Colony Forming Units (CFU) per Gram

0

1

2

3

4

5

6

7

8

0 5 10 15 20 25 30

PlaceboVaccine

28 Samplings (AM/PM for 14 Days)

Lo

g 1

0 C

FU

/ g

81

2008 Field Study: Salmonella in Cull Dairy CowsGuy Loneragan – WTAMU (Western Texas A&M University)

Loneragan, GH et al. Salmonella in Cull Dairy Cattle of the Texas High Plains. 89th Annual Meeting of the Conference of Research Workers in Animal Diseases, December 7-9, 2008, Chicago, Illinois

● Enrolled 9 West Texas dairies (all >2,000 cows)

– Sampled 706 cows culled from the dairies, either on site or at regional sales barn

● Cultured for Salmonella

– Serotype, susceptibility testing, quantification

● Salmonella recovered from 32.6% of samples

– Varied by month and dairy

– Dairy burden ranged from 4.4% to 86.3%• Within-herd burden remained relatively constant over time

Loneragan, GH et al. Salmonella in Cull Dairy Cattle of the Texas High Plains. 89th Annual Meeting of the Conference of Research Workers in Animal Diseases, December 7-9, 2008, Chicago, Illinois. Vaccine = Salmonella Newport Bacterial Extract Vaccine 82

Salmonella Prevalence in Cull Dairy Cows: 9 Large Texas Dairies

0

20

40

60

80

100

1 2 3 4 5 6 7 8 9

Pre

vale

nc

e,

%

Individual Dairies

Vaccine

Vaccine Vaccine

Hermesch DR, Thomson DU, Loneragan GH, Renter DR, White BJ. Effects of a commercially available vaccine against Salmonella enterica serotype Newport on milk production, somatic cell count, and shedding of Salmonella organisms in female dairy cattle with no clinical signs of salmonellosis. AJVR 2008;69(9):1229-1234Vaccine = Salmonella Newport Bacterial Extract Vaccine 83

Effect of Vaccination on Milk Production in Sub-clinically Infected Cows

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 8920

40

60

80

100

ControlVaccinates

Days in Milk

Pa

rity

Ad

jus

ted

Milk

Pro

du

cti

on

Averaged over time, vaccinated animalsproduced 2.5 lbs more milk per day (P<0.05)

* At 30 to 60 days of lactation

Effect of Vaccination with Salmonella Newport Bacterial Extract Vaccineon SCCs (cells/mL)* (P=0.01)

Control Cattle Vaccine0

100

200

300

400

500

SC

Cs

(cel

ls/m

L)

x 1,

000

84

Control of E. coli O157 with E. coli Bacterial Extract Vaccine

Thomson DU, Loneragen GH, Thornton AB, et al., Use of a Siderophore Receptor and Porin Proteins-Based Vaccine to Control the Burden of Eschericia coli O157:H7 in Feedlot Cattle. Foodborne Pathogens and Disease 2009; Vol. 6, Number 7, 871-877

● Same technology platform as Salmonella Newport Bacterial Extract vaccine– SRPs harvested from stx-negative E. coli O157:H7

● Study conducted in commercial feedlot– Thomson et al. FPD. 2009;6:871-877

● Animals randomized from source pens into 20 pens of 60 to 70animals per pen

● 10 pens vaccinated d0, d21, d42– Other 10 matched pens received placebo

• Study personnel masked as to treatment allocation

● Sampled d0, d42, and d98

Study Led by Daniel U. Thomson, K State



d0 d42 d980

5

10

15

20

25

30

Vaccinates Placebo

E. c

oli

0157

Pre

vale

nce



d0 d42 d980

5

10

15

20

25

30

Vaccinates Placebo

E. c

oli

0157

Pre

vale

nce

Concentration on d980

1

2

3

4

0.90

2.53

Lo

g10

MP

N/g

87

A “Food System” Approach to Pathogen Reduction

Reduction Begins at the Source….

PreparationInterventions

Harvest & Post-harvestInterventions

Pfizer Animal HealthE. Coli Bacterial Extract Vaccine

ConsumersHarvest

Source: Emerging Options to Control E. coli O157:H7 Pre-harvest; Guy H. Loneragan, West Texas A&M University Canyon, Texas, USA; June 24-25, 2009, Angers, France 88

Another Hurdle Within a System

E. coli O157

Currently Multiple Post-harvest Controls

E. coli O157

Most of the time, within plant interventions effectively mitigate what comes in on the cattle

Pre-harvest

http://images.google.com/imgres?imgurl=http://www.koolomurt.com.au/images/koolomurt%20steers%20feedlot.jpg&imgrefurl=http://www.koolomurt.com.au/koolomurt.htm&usg=__AuY2GRR5UOFnqcoBZcQ-rUOh6rM=&h=327&w=500&sz=46&hl=en&start=22&sig2=QPmeKcmLrFJOf5ePUyR3Jw&itbs=1&tbnid=c_fua1uyAgfFKM:&tbnh=85&tbnw=130&prev=/images?q=feedlot&gbv=2&ndsp=20&hl=en&sa=N&start=20&ei=zoVoS-zjJcfK8Qap643qCA




E. coli O157E. coli O157 E. coli O157

Sometimes, these interventions fail – E. coli O157 detected in: 0.9% of trim combos; 0.33% of GB (ground beef) samples

ConsumersHarvestPre-harvest





E. coli O157 E. coli O157

SR

P

For example, if pre-harvest prevalence reduced from x to y, what is the extent of the impact on z (rate of microbial defects)

ConsumersHarvestPre-harvest


outcomes analysis of e. coli o157:h7 vaccination in beef cattle

Education

risk analysis

h7 vaccination

e coli o157

outcomes analysis of

riskbased analysis

farmfood animal

industry worry

national animal disease