Writing in the latest issue of Emerging Infectious Diseases Journal (June 2003), Martin Wiedmann, Cornell assistant professor of food science, describes examining bacterial samples from listeriosis victims from the New York State Department of Health obtained between 1996 and 2000. By matching strains of the bacterium using DNA fingerprint methods, Wiedmann and his colleagues were able to show connections between cases of listeriosis in the state. Previously it was believed that the vast majority of these cases occurred in isolation.
Through PulseNet, the national molecular subtyping network for food-borne disease surveillance operated by the Centers for Disease Control and Prevention (CDC) in Atlanta, a larger number of human listeriosis infections are likely to be recognized as occurring in clusters, making it easier to link them to specific food sources, says Wiedmann.
The bacteriumListeria monocytogenes is found in soil and water and can contaminate vegetables and infect animals. The bacterium has been found in a variety of raw foods, such as uncooked meats and vegetables, as well as in processed foods that become contaminated after processing, such as soft cheeses and cold cuts.
"Most cases of listeriosis are thought to be sporadic, but public health officials who encounter it should be looking for clusters," says Wiedmann. "If we are on the lookout for clusters, then perhaps we can stop an outbreak after a few cases and save people who otherwise might have died during the outbreak. Traditional epidemiological surveillance alone may not
Contact: Blaine P. Friedlander Jr.
Cornell University News Service