At this point in the investigation, romaine lettuce and ground beef/hamburgers are the leading hypotheses. However, it is still early in the investigation so other plausible hypotheses should be explored.
Question 2-3: What would you do to develop other hypotheses?
- Review the literature for sources of past E. coli O157:H7 outbreaks (see Tools below)
- Check Outbreak Summaries to review the sources of past E. coli O157:H7 outbreaks in Canada
- Determine if the same PFGE pattern has been observed elsewhere in the food chain and outside Canada by asking:
- Interview cases with a standardized questionnaire to identify other common food exposures and to determine if cases report consumption of other food items at higher than expected levels.