Chapter 3

Cyclospora cayetanensis

Ynes R. Ortega

Abstract

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.

Total Pages: 68-81 (14)

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