The Single Interviewer Approach for Enteric Diseases

1. 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 • The Single Interviewer Approach (SIA) • What is the SIA? • Use at the Provincial Level • Use at the Health Unit Level • 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

6. Potential Advantages of the SIA

7. 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.

8. What is the “Numbers” Impact of Provincial Outbreaks? * 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.

9. Case and Contact Management for a Provincial Outbreak 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 • 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. 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

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.

11. 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

12. 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.

13. The SIA Working Group

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 (Galesicet 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

21. Other Investigation Tools • Online Survey Tools • Fluid Surveys • SalmonellaTyphimurium 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

22. Summary • Single Interviewer Approach • Provincial Level • Health Unit Level • Standardized Questionnaires • Online Survey Tools • Consumer Loyalty Cards