An outbreak of Shigella sonnei gastroenteritis on colorado river raft trips

Merson, M. H. (Enteric Disease Section, Bacterial Disease Branch, Center for Disease Control, Atlanta, Ga. 30333), D. A. Goldmann, K. M. Boyer, N. J. Peterson, C. Patton, L. G. Everett, H. Downs, A. Steckler and W. H. Barker, Jr. An outbreak of Shigella sonnei gastroenteritis on Colorado River raft trips. Am J Epidemiol 100:186-196, 1974.-In the summer of 1972 an extensive outbreak of acute gastroenteritis occurred among passengers and boatmen on Colorado River raft trips. The illness was characterized by diarrhea, abdominal cramps, and fever, and laboratory results indicated that the outbreak was caused by Shigella sonnei. Epidemiologic evidence suggested that illness originated among boatmen and spread to passengers primarily by person-to-person transmission. No common food or water vehicle could be identified as the source of the outbreak. A bacteriologic and chemical analysis of water from the Colorado River and some of its tributaries demonstrated that this water is unsuitable for drinking unless purified. As a result of the outbreak, the Colorado River Health Committee was created to establish guidelines for food and water handling and sewage disposal aboard the rafts and to initiate a health training course for boatmen.