Submitted to: Morbidity and Mortality Weekly Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/21/1998
Publication Date: N/A
Interpretive Summary: Leptospirosis is a widespread bacterial disease that infects animals and humans. This infection is maintained in a variety of domestic and wild animal species. These maintenance hosts shed the organism in their urine and serve as a reservoir of infection for other animals and human beings. Leptospirosis is an important cause of reproductive failure in cattle and swine; control of the disease in animals is important for animal health, a well as public health. A large outbreak of leptospirosis has occurred in humans that have been swimming in a large recreational lake in Central Illinois. It is important that the source of the organism in this outbreak be identified in order to develop sound strategies to prevent further human infections and to prevent exposure of domestic livestock in the area. This publication reports on the results of the epidemiologic investigation to this point and is the result of a collaborative effort between USDA, DHHS, and State of Illinois public and animal health scientists.
Technical Abstract: Since July 14, 1998, the Illinois Department of Health, the Wisconsin Department of Health, additional U.S. state and local health departments, USDA, and CDC have been investigating an outbreak of acute febrile illness among athletes from 44 states who participated in triathlons held in Springfield, Illinois on June 21, 1998, and in Madison, Wisconsin on July 5, 1998. This report updates the ongoing investigation of this outbreak through August 7, 1998. Of the 1133 athletes surveyed thus far, 108 athletes who participated in one or both events described an illness meeting the case definition. Acute-phase serum specimens have been tested for 273 of 887 athletes who participated in the Illinois triathlon. Of these, 64 belonged to the 89 case-patients who participated in the Illinois event. Twenty-seven (42%) of 64 case-patients and 3 (1%) of 273 athletes not meeting the case definition tested positive by PanBio ELISA. All 27 case-patients with a positive PanBio ELISA tested positive by confirmatory MAT with highest titers to serovars grippotyphosa and bratislava. To date, 202 Springfield-area case-patients have been identified, and 120 (59%) have had acute-phase serum specimens tested at CDC by PanBio ELISA. Six of these individuals' specimens have tested positive by PanBio ELISA, and of these, MAT confirmed leptospirosis in three case-patients. CDC, in collaboration with state and local health departments and USDA, is continuing to pursue epidemiologic, laboratory, and environmental investigations to further define this outbreak. The objectives of these investigations are to identify additional cases among occupational and recreational users of Lake Springfield, to determine the etiology of illness, and to develop prevention and control measures for the outbreak.