The coccidian parasite Cyclospora cayetanensis can cause gastrointestinal
illness. It has been associated with consumption of contaminated foods, particularly
those eaten raw or minimally processed. First considered a cyanobacteria or coccidianlike
organism, in the early 1990s it was characterized as a member of the Cyclospora
genus based on morphological properties. This parasite has been associated with
travelers’ diarrhea. To date, there is no animal reservoir identified for C. cayetanensis.
Waterborne outbreaks have also been reported. In July of 1990, 21 household staff
physicians developed diarrheal illness and analysis of their stool specimens showed
organisms consistent with Cyclospora oocysts. Epidemiological investigations
implicated tap water as the likely source of the outbreak. In another instance, in 1994,
British soldiers and their dependents stationed in Nepal developed cyclosporiasis.
Local drinking water with chlorine concentrations of 0.3-0.8 ppm was associated with
this outbreak and Cyclospora oocysts were isolated from the water. Additionally,
imported berries, salad greens, and herbs were associated with foodborne outbreaks of
cyclosporiasis in the U.S., Canada, and European countries in the late 1990s. In 2013,
2014, and 2015 C. cayetanensis caused significant outbreaks in the U.S. and were
epidemiologically associated with imported salad greens and cilantro. Cyclospora is
resistant to many commonly used sanitizers and certain environmental conditions
which are found in many locations used to process/package produce. Oocysts can be
inactivated by either freezing or heating. Tools for traceback studies and in vitro or in
vivo models to propagate this parasite are currently not available.
Keywords: Coccidia, Control, Cyclospora cayetanensis, Eimeriidae,
Epidemiology, Foodborne, Transmission, Waterborne.
