AN OUTBREAK OF CRYPTOSPORIDIOSIS FROM FRESH-PRESSED APPLE CIDER

Background.-Recent waterborne outbreaks have established Cryptosporidi um as an emerging enteric pathogen, but foodborne transmission has rar ely been reported. In October 1993, an outbreak of cryptosporidiosis o ccurred among students and staff attending a 1-day school agricultural fair in central Maine. Design.-Environmental/laboratory investigation and cohort study. Participants.-Attendees of the fair and their house hold members. Main Outcome Measures.-Clinical or laboratory-confirmed cryptosporidiosis. Clinical cryptosporidiosis was defined as 3 days of either diarrhea (three loose stools in a 24-hour period) or vomiting. Results.-Surveys were completed for 611 (81%) of the estimated 759 fa ir attendees. Among attendees who completed the survey, there were 160 (26%) primary cases. Cryptosporidium oocysts were detected in the sto ols of 50 (89%) of 56 primary and secondary case patients tested. The median incubation period was 6 days (range, 10 hours to 13 days); the median duration of illness was 6 days (range, 1 to 16 days). Eighty-fo ur percent of primary case patients had diarrhea and 82% had vomiting. Persons drinking apple cider that was hand pressed in the afternoon w ere at increased risk for cryptosporidiosis (154 [54%] of 284 exposed vs six [2%] of 292 unexposed; relative risk, 26; 95% confidence interv al, 12 to 59). Cryptosporidium oocysts were detected in the apple cide r, on the cider press, and in the stool specimen of a calf on the farm that supplied the apples. The secondary household transmission rate w as 15% (53/353). Conclusions.-This is the first large cryptosporidiosi s outbreak in which foodborne transmission has been documented. It und erscores the need for agricultural producers to take measures to avoid contamination of foodstuffs with infectious agents common to the farm environment.