The Single Interviewer Approach for Enteric Diseases

APHEO General Meeting

November 22, 2013

Dean Middleton, BSc, DVM, MSc.

Enteric, Zoonotic and Vector-Borne Diseases Unit

2

Outline

1. The Single Interviewer Approach (SIA)

2. What is the SIA?

3. Use at the Provincial Level

4. Use at the Health Unit Level

5. Other Initiatives

3

What is The Single Interviewer Approach?

• The administration of questionnaires on cases that occur via one, or a small number, of interviewers• Federal Field Epidemiologists use the SIA frequently in investigations

• Contrast with the Multiple Interviewer Approach• Numerous interviewers administering questionnaires in numerous

jurisdictions

4

5

6

Item Multiple Interviewer Approach

Single Interviewer Approach

Questionnaire Data Consistency/Quality/Comparability

Cases interviewed by numerous investigators leads to inconsistencies.

Better data consistency and comparability. Every case given priority.

Hypothesis Generation

Potential hypotheses not discussed among all of the interviewers.

1 or 2 interviewers synthesize all information gathered to generate hypotheses.

Hypothesis Testing Inability to quickly respond to items identified as potential sources of the outbreak.

Can explore the hypotheses on the very next interview by comparing brands, purchase dates, etc.

Data Analysis Primarily running “frequencies” of “closed ended” questions.

1 or 2 interviewers synthesize “open ended” question data better.

Potential Advantages of the SIA

The Single Interviewer Approach

Provincial Outbreaks

• Potential advantages achieved for certain provincial outbreaks.

• These outbreaks would primarily include those where it is suspected that a food item is being distributed to two or more health units.

7

8

What is the “Numbers” Impact of Provincial Outbreaks?

2012 2011Number of enteric ESDs

12 15Number of ESDs that could have used SIA 5 5

Number of cases involved with the SIA 260 704 *Total number of enteric cases 8,952 9,022Approximate percent of total enteric cases 2.9% 7.8% *

* The S. Enteritidis case-control study is included in these numbers. An ESD was not issued for this investigation. The investigation included 630/9,022 = 7.0% of enteric cases.

Source: iPHIS weekly and monthly reports.

Case and Contact Management for a Provincial Outbreak

9

HU’s contact case. Inform the case that they may be contacted again if they are identified as being part of an outbreak

HU’s enter the case’s contact information (e.g., phone number)

in iPHIS

The single interviewer contacts the case 2-3 days later, after the

appropriate laboratory typing/ subtyping findings identify that the

case is included in the outbreak

Notes:• Process will be the same as

currently used in outbreaks involving Federal Field Epidemiologists.

• The interview burden on cases will be similar in outbreaks regardless of whether the SIA or MIA is used.

10

The SIA in Health Units

• The advantages of the SIA are also applicable at the health unit level

• The “model” is … one interviewer interviews all the cases of one pathogen (e.g., E. coli)

• Surveillance for the pathogen improves within the health unit

• One interviewer can synthesize all of the information pertaining to the one pathogen within the health unit

• This assists greatly if the outbreak becomes a provincial outbreak.

The SIA in Health Units

• 12 health units are currently using the SIA.

• Different models are used in these health units

• Different models depending on factors such as;• Health unit population• Number of staff• Health unit geographical size

11

Adopting the Single Interviewer Approach

• The “SIA Working Group” supports adopting the SIA.• Representation from 10 health units• “Use of the Single Interviewer Approach as a Best Practice for

Investigation of Enteric Diseases in Ontario” document.

• The work of the “Standardized Questionnaire Working Group” is expected to compliment the SIA.

12

13

The SIA Working Group

Jurisdiction Name Title

TOR Anne Arthur Manager (A), Communicable Diseases Surveillance Unit

PTC Edwina Dusome Manager, Infectious Disease Programs

MSL Joanne Dow (Co-Chair) Public Health Nurse

NIA Heather Hague Manager, Infectious Diseases

MOHLTC Melissa Helferty Epidemiologist

PHO Christina Lee Senior Public Health Consultant

LGL Joan Mays Manager, Community Health Protection

PHO Dean Middleton (Co-Chair)

Senior Public Health Epidemiologist

PHO Stephen Moore Manager, Enteric, Zoonotic and Vector-Borne Diseases Unit

YRK Omar Ozaldin Program Manager, Control of Infectious Diseases

SUD Cindy Rocca Environmental Support Officer

WDG Janice Walters Manager, Control of Infectious Diseases

OTT Lindsay Whitmore Epidemiologist

14

Conclusions

Single Interviewer Approach

• The SIA provides numerous advantages at the health unit and provincial level compared with the MIA

• It is hoped that epidemiologists will support adopting the Single Interviewer Approach for enteric disease investigations

15

Enteric Standardized Questionnaires

• Currently, the 36 health units use different questionnaires

• Constraints in comparison of questionnaire information between health units

• Health Unit staff have asked about creating standardized questionnaires

16

The “Shotgun” Questionnaire

• Originated in the late 1990’s

• 15 – 20 pages

• 8 point font

• Mind numbing for the interviewee and interviewer

• Not likely to obtain accurate information

17

What are the Questions on Questionnaires?

• How to improve a questionnaire to get better information?

• What is the optimal length?

• How can the accuracy of the interviewee’s answers be improved?

• How can the flow or the question order be improved?

• When should the case be allowed to self administer the questionnaire?

• Is there a need for a standardized questionnaire?

• How can the transfer of data from the questionnaire to iPHIS be improved?

18

Questionnaire Review Process

Literature Review

• Searched MEDLINE and PsycINFO

Example Finding

• Answers to questions positioned later in the questionnaire were faster, shorter, and more uniform than answers to questions positioned near the beginning (Galesic et al, 2009)

19

Jurisdictional Scan

Canadian

• BC CDC

• C-Enternet

• PHAC

• Correctional Services Canada / Canadian Field Epidemiology Program

USA

• US CDC Foodcore

• Minnesota, Utah, Oregon, Wisconsin

Outside of North America

• OzFoodNet

20

The Standardized Questionnaire Working Group

Health Unit Name Health Unit Name

NWR Sandra Krikke HAL Joanna Oliver

SUD Holly Browne WAT Amy MacArthur

ALG Gary Leith PTC Edwina Dusome

LAM Janet Bowls PEE Liz Haydu

OXF Kitty Chan DUR Ross MacEachern

MSL Joanne Dow TOR Gemma Vena

HUR Erika Clark SMD Jason Riewe

GBO Stephanie Nickels HPE Lindsey Bearnes

HAM Debra Marsillo LGL Joan Mays

NIA Lorrie Ross OTT Melissa Guy

WDG Katherine Paphitis YRK Omar Ozaldin

BRN Rose Corby PHAC Andrea Nesbitt

MOHLTC Melissa Helferty

Other Investigation Tools

• Online Survey Tools

• Fluid Surveys

• Salmonella Typhimurium phage type 10• February 2013• Outbreak associated with reptiles/feeder mice• Post outbreak review focused on use of the online tool

• Consumer Loyalty Cards• Working Group planned• Work has begun with retailers

21

22

Summary

• Single Interviewer Approach• Provincial Level• Health Unit Level

• Standardized Questionnaires

• Online Survey Tools

• Consumer Loyalty Cards