Epidemiology and Infection

Research Article

An outbreak of cryptosporidiosis associated with a resort swimming pool

W. R. MacKenziea1, J. J. Kazmierczaka2 and J. P. Davisa2 c1

a1 CDC, EPO, DFE, MS C-08, 1600 Clifton Road, NE Atlanta, GA 30333

a2 Wisconsin Division of Health, Bureau of Public Health, 1400 East Washington Ave., Room 96, Madison, WI 53703


An outbreak of cyptosporidiosis occurred in late April 1993 among resort hotel guests which was temporally associated with, but geographically distant from, a massive waterborne outbreak of cryptosporidiosis in Milwaukee, Wisconsin, that occurred in late March and early April of 1993. A case-control study was performed among groups with members who reported illness and among a systematic sample of groups who stayed at the resort hotel during the risk period. Of 120 persons interviewed, 51 (43%) met the case definition. Swimming in the resort hotel's pool was significantly associated with case status (OR = 9·8; 95% Cl 3·4, 29·7), as was consumption of ice from the hotel's ice machines (OR = 2·3; 95% Cl 1·01, 5·2). When analysis was restricted only to laboratory-confirmed cases and controls, swimming pool use was the only risk factor significantly associated with illness (OR=13·0; 95%C1 2·6, 88·7). Following waterborne outbreaks of cryptosporidiosis associated with water supplies, swimming pools should be considered as possible ongoing sources for transmission regionally.

(Accepted May 24 1995)


c1 Author for correspondence.