PBH321: INTRODUCTION TO EPIDEMIOLOGY

M5D1: It’s a foodborne outbreak! What next?

Module 5

This week’s discussion will focus on a real world foodborne outbreak that was investigated simultaneously by two states.  By the end of this activity, you will be able to discuss case control studies in the context of a foodborne outbreak, and recognize the impact of timely epidemiologic investigations on public health.  

This week, we’ll begin the discussions by exploring foodborne outbreaks. Remember that an active discussion is key to an engaging discussion. Be sure to read what others have written and add substantively to the discussion. Time goes fast so start right away!

The first question is based on what you have learned this term so you can engage in discussion immediately.

• Recalls of food items typically occur as a result of epidemiologic investigations and studies.  Have you ever heard about a recall of a particular food item?  Which one(s)?  Did you change your behavior as a result?

For the rest of the discussion, your task is to read: A Multistate Outbreak of Escherichia coli O157:H7 Infections Linked to Alfalfa Sprouts Grown from Contaminated Seeds (Links to an external site.), and to review the module notes, video, and readings in the text.?

As you read the study think about the choice of study design, and if you would make the same decision.  The measure of association reported in this study is a matched odds ratio.  Although we did not cover matching in this module, what you need to know is that cases and controls are matched by certain socio-demographics in an attempt to make the groups more similar (only differ by outcome).  The interpretation of a matched odds ratio is the same as what you learned for the odds ratios in this module. 

Now applying what you’ve learned from the readings and video, let’s go through the rest of the discussion together, one question at a time.

After completing your readings, answer the questions below.

1. Could the research question addressed in these case-control studies have been conducted using a cohort study? Why or why not?
2. What were some advantages/disadvantages of using case-control study design for this purpose?
3. Given the matched odds ratios found in both studies, would you have supported recalling the sprout seeds if you were epidemiologist in Michigan or Virginia?

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