Cyclospora cayetanensis, a pathogenic protozoon that causes diarrhea, cramps, and fever in humans. The microorganism, a coccidian parasite about 0.01 mm in diameter, was identified in 1979, after the first known cases of the infection were diagnosed. Before 1996 only three outbreaks of Cyclospora infection had been reported in the United States and Canada. It is diagnosed much more frequently now, and is often referred to as “traveler’s diarrhea.” Although Cyclospora is transmitted by the fecal-oral route, person-to-person transmission is unlikely because oocytes require days to weeks under favorable conditions to become infectious after leaving an infected host.
