The First 24-48… Initial steps to a foodborne outbreak investigation

1. Suzanne Wilson, MPH Food and Waterborne Disease Epidemiologist WVDHHR-Division of Infectious Disease Epidemiology November 17, 2010 The First 24-48…Initial steps to a foodborne outbreak investigation

2. Objectives • Definition of a Foodborne Outbreak • Preparation steps for an outbreak investigation • Initial action steps for an outbreak investigation • Conducting good interviews

3. Definition of a FBO • Two or more persons who experience a similar illness after ingestion of a common food

4. Before an Outbreak OccursBe Prepared! • Identify Members of Investigation Team • Nurse/Epi, Environmental, Laboratory • Delineate roles/activities for team members • Know how to obtain additional resources • Maintain a network and list of key contacts

5. Before an Outbreak OccursBe Prepared! • Be educated on clinical features of specific foodborne illness and the specific factors that contribute to these illnesses – stay current! • Establish a system for intake and review of complaints and illness reports • Know your baseline- How many of these do we “normally” get?

6. When You Get the Initial Call… • Record information • Signs and symptoms • Date and time of onset • Obtain 72 hour food history • Any other people who are ill • How many people at the activity • Any medical treatment or testing

7. When You Get the Initial Call… • If random complaint • check complaint log for similar reports • If reporting on an event (i.e. banquet, wedding) • Obtain information on event organizer • Contact information for attendees

8. Collect information • Contact others on list to identify other potential cases • Systematically look at information to determine plausibility of an outbreak • Are reported symptoms consistent • Any common exposures USE A LINELIST TO DO THIS!

9. Start a Linelist • Keeps all information in one place • Allows for systematic evaluation of cases • Used to make an epicurve • Sample can be found at: http://www.wvidep.org/AZIndexofInfectiousDiseases/OutbreaksorClustersofAnyIllness/tabid/1535/Default.aspx

10. Sample Linelist

11. What does this epi-curve tell you about the outbreak? Person-to-Person

12. What does this epi-curve tell you about the outbreak? Point-source

13. Once you have determined you have an outbreak • Develop a case definition • Conduct hypothesis generating interviews • In depth and detail oriented • About 8 to 10 cases • Develop questionnaire • Broad range of exposures

14. Environmental • If outbreak is centered around an event or location • Conduct a risk assessment of the facility and processes • Embargo any leftover food • Track food flow through the facility • Look for what went wrong “When you have a foodborne outbreak, more than one thing went wrong.” Dr. Frank Bryan, CDC

15. Questionnaire Template • Handout

16. Summarize Initial Steps • Collect Information on Line listing • Determine transmission mode • Develop case definition • Hypothesis Generating Interviews

17. Conduct Interviews • Can be used for : • Verifying outbreak • Searching for additional cases • Determining if cases are associated • Collecting data to determine possible sources A good interview is a MUST!

18. Interviewing Skills

19. Interviewing Goals • Be consistent in interviews • Do your homework to minimize repeat contacts • Target questions to greatest degree possible

20. Before the Interview Begins… • Be prepared-conduct training if needed • Select form to be used

21. During the Interview • Establish rapport • Identify self, organization, and reason for investigation • Start with easy questions • Demographics, etc. • Let them know you may be need to re-contact them

22. Interview Tips • When they cannot remember meals: • Ask about food preferences • Can rule in/out some foods • Identify key days and dates to jog memory (use a calendar) • Review receipts or checkbook • Buffets-need to clearly describe each food item • Recall is better for items from a menu

23. Interview Tips • Last Meal Bias • Take multi day food history • Explain that pathogens may take days to cause illness • Ask if leftovers are available for testing • Don’t forget the details • Exact restaurant locations

24. Interview Tips • Ask questions as written on form • Review form before ending interview • Ask if individuals have • Unanswered questions • Additional information • Thank them for their time!!

25. Interview Exercise • Break up into groups of three • Interviewer • Interviewee • Observer