Emerging Pathogens Associated with Infectious Diarrhea.

In recent years, emerging microbial pathogens associated with infectious diarrhea have caused significant morbidity and mortality. Although sporadic cases of infectious diarrhea have occurred worldwide in the past, recent outbreaks in the United States traced to contaminated water or food have raised concerns about the safety of the water supply and the adequacy of surveillance of the food supply and foodborne diseases. In 1993, Cryptosporidium parvum, an important cause of unrelenting diarrhea and severe weight loss in AIDS patients, was associated with the largest outbreak of infectious diarrhea caused by contaminated municipal water that has ever been reported in the U.S. During the early summer of 1996, a major outbreak of Cyclospora cayetanensis that infected approximately 1,500 persons in 20 states, Washington, D.C. and two Canadian provinces was reported from North America. The suspected food vehicle in this outbreak was contaminated raspberries imported from Guatemala. In addition to these coccidian protozoa,Escherichia coli 0157:H7, first recognized in 1982 as a cause of hemorrhagic colitis, has recently been responsible for a multi-state outbreak in the U.S. due to contamination of commercial ground beef, and an outbreak in Japan that infected over 9,500 persons, two-thirds of whom were children. The contaminated food vehicle in the latter outbreak, although suspected to be radish sprouts, remains unknown. These recent massive outbreaks underscore the importance of a well-established public health infrastructure and an effective surveillance system for the early identification and reporting of infected patients that will lead to appropriate epidemiologic investigations and the rapid detection of contaminated vehicles.