AN OUTBREAK IN 1996 OF CYCLOSPORIASIS ASSOCIATED WITH IMPORTED RASPBERRIES

Background Cyclospora cayetanensis is a parasite that causes gastroent eritis. Until last year most of the documented cases of cyclosporiasis in North America were in overseas travelers. In 1996, a large outbrea k of cyclosporiasis occurred in North America. We investigated this ou tbreak. Methods Health departments solicited information from clinicia ns and laboratories on cases of cyclosporiasis, which were then report ed to the Centers for Disease Control and Prevention and to Health Can ada. We conducted retrospective cohort studies for the cases associate d with events (e.g., luncheons) and attempted to identify the sources of the implicated food. Results A total of 1465 cases of cyclosporiasi s were reported by 20 states, the District of Columbia, and 2 province s. Of these cases, 978 (66.8 percent) were laboratory confirmed and 72 5 (49.5 percent) were associated with 55 events that were held from Ma y 3 through June 14. Raspberries were definitely served at 50 events a nd may have been served at 4 events, For 27 of the 41 events for which adequate data were available (65.8 percent), the associations between the consumption of berries (raspberries with or without other berries ) and cyclosporiasis were statistically significant (P<0.05). For all 29 events for which there were good data, the raspberries definitely c ame from Guatemala (21 events, 72.4 percent) or may have come from Gua temala (8 events, 27.6 percent). As few as five Guatemalan farms could have accounted for the 25 events for which the raspberries could be t raced to a single exporter per event. The mode of contamination of the raspberries remains unclear. Conclusions This large outbreak of cyclo sporiasis in North America in 1996 was associated with the consumption of Guatemalan raspberries. The outbreak illustrates the need to consi der that a local cluster of foodborne illness may be part of a widespr ead outbreak and to pursue investigations of the source of the implica ted vehicle. (C) 1997, Massachusetts Medical Society.