Cyclospora cayetanensis: A review, focusing on the outbreaks of cyclosporiasis in the 1990s

Cyclospora cayetanensis, a coccidian parasite that causes protracted, relap sing gastroenteritis, has a short recorded history. In retrospect, the firs t 3 documented human cases of Cyclospora infection were diagnosed in 1977 a nd 1978, However, not much was published about the organism until the 1990s . One of the surprises has been the fact that a parasite that likely requir es days to weeks outside the host to become infectious has repeatedly cause d foodborne outbreaks, including large multistate outbreaks in the United S tates and Canada. In this review, I discuss what has been learned about thi s enigmatic parasite since its discovery and what some of the remaining que stions are. My focus is the foodborne and waterborne outbreaks of cyclospor iasis that were documented from 1990 through 1999. The occurrence of the ou tbreaks highlights the need for health care personnel to consider that seem ingly isolated eases of infection could be pare of widespread outbreaks and should be reported to public health officials. Hearth care personnel shoul d also be aware that stool specimens examined for ova and parasites usually are not examined for Cyclospora unless such testing is specifically reques ted and that Cyclospora infection is treatable with trimethoprim-sulfametho xazole.