William E. Keene, Ph.D., M.P.H.
Senior Epidemiologist, Acute and Communicable Disease Program,
Oregon Public Health Services
Case studies of three important foodborne disease outbreaks are presented to illustrate how disease surveillance works in the United States and the evolution of outbreak investigative methods. These outbreaks can be reviewed in detail in the original literature (see also Barrett et al., 1994; Bell et al., 1994; CDC, 2004; Cody et al., 1999; Griffin et al., 1994).
Outbreak 1 was the 1992-1993 Jack-in-the-Box outbreak of Escherichia coli O157:H7 infections that affected several western states. The outbreak was caused by widespread undercooking of contaminated frozen ground beef hamburger patties at many outlets of the Jack-in-the-Box fast food chain. Although infections from this source began to appear in California and Nevada as early as November 1992, the outbreak was not detected until it reached Washington state in late December. At that time only Washington state was conducting routine surveillance for these infections. In California and Nevada, in contrast, the infection was not reportable, and few laboratories ever used the special media needed to identify the pathogen. Physicians and the general public there were largely unaware of this pathogen; in the absence of recognized outbreaks, there was no publicity and no public education. This outbreak was a landmark event in modern epidemiological history. It had an enormous effect on the public’s perception of the problem of foodborne illness. The political ripples from this event continue to this day. We can quite reasonably talk about foodborne disease epidemiology in the United States before and after Jack-in-the-Box. The outbreak illustrates how large outbreaks with many hospitalizations and even fatalities can