However, within 48 hours of initiating a case-control study, a nationally distributed food product was identified as the vehicle, and the nationwide scope of the outbreak was documented. This was an example of consequential epidemiology. When the association between food consumption and SE was announced, the evidence implicating a particular brand was limited to a single case-control study of 15 matched pairs. Laboratory isolation of SE from official samples was not reported until 10 days later. This prompt action, based on epidemiologic data, prevented at least 10 days of potential exposure for thousands of consumers.
Consequential epidemiology produces results that translate into disease prevention.
We need to continue to develop models for how to rapidly evaluate and act on epidemiologic data and how to better coordinate activities regionally and nationally. A critical element of the success of this type of foodborne disease surveillance is the specificity with which we can match isolates that may be epidemiologically linked. Molecular subtyping schemes such as pulsed-field gel electrophoresis can greatly improve identification of clusters of the same organisms such as particular Salmonella serotypes. Another example involved analysis of a typical epidemiologic curve for a seemingly single outbreak. When isolates were analyzed, however, a cluster of small outbreaks was found.