A Multi-state Outbreak of E. coli O157:H7 Infection

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Jeanette Stehr-Green
Date published
Apr, 2002
Last updated
22 Jan 2020


This case study is based on two real-life outbreak investigations undertaken in Michigan and Virginia in 1997. They were eventually linked to consumption of alfalfa sprouts.

Learning Objectives: 

  • Describe the unique role the laboratory can play in the detection and investigation of a foodborne disease outbreak;
  • Perform in-depth interviews of selected case-patients to generate hypotheses about the source of an outbreak and mode of transmission;
  • Determine the most efficient epidemiologic study design to test a hypothesis (including the case definition and appropriate comparison group);
  • List three ways to select a comparison group for a study and the advantages and disadvantages of each method;
  • List detailed product information that will facilitate a traceback procedure; and
  • Discuss the relative merits of an intervention based on changes in product processing (or design) versus changes in consumer or producer behaviors.