(Optional) - Steps in the Investigation of a Disease Outbreak

Most outbreak investigations involve the following steps:

  1. Preparation for the investigation
  2. Verifying the diagnosis and establishing the existence of an outbreak
  3. Establishing a case definition and finding cases
  4. Conducting descriptive epidemiology to determine the personal characteristics of the cases, changes in disease frequency over time, and differences in disease frequency based on location.
  5. Developing hypotheses about the cause or source
  6. Evaluating the hypotheses & refining the hypotheses and conducting additional studies if necessary
  7. Implementing control and prevention measures
  8. Communicating the findings

Some of these steps may be conducted simultaneously, and the order may vary depending on the circumstances. For example, if new cases are continuing to occur and there are steps that can be taken to control the outbreak and prevent more cases, then certainly control and prevention measures would take top priority.

Optional Additional Resources

General Information on Outbreak Investigations

For an overview of outbreak investigations for foodborne illness see the CDC web page linked here. Other good general sources of information on how to conduct outbreak investigations can be found in the University of North Carolina (UNC) online Focus on Field Epidemiology series. The following links to online articles may be of interest:

Volume 1

Volume 2:

Another good general resource is "Hepatitis in Sparta." This is an online interactive teaching case that thrusts the student into the role of investigator trying to determine the source for an outbreak of hepatitis cases in the town of Sparta.