Cyclospora cayetanensis, a coccidian protozoan, causes a diarrheal illness first described in humans in 1979.
- Worldwide distribution, with areas of endemic infection (Nepal, Peru, Haiti, Guatemala, Indonesia)
- People living in endemic areas have a shorter illness or may be asymptomatic carriers.
- Cyclospora can be an opportunistic infection in human immunodeficiency virus patients.
- In the United States, infection occurs primarily in spring and summer.
- In the United States and Canada, cases are associated with consumption of imported fresh produce.
- Fresh produce, especially raspberries, cilantro, and salad mixes, should be washed thoroughly before being eaten, although this still may not entirely eliminate the risk of transmission.
- Avoid consumption of waste water and, in endemic areas, avoid consumption of tap water.
- Infected patients excrete noninfectious unsporulated oocysts in their stool.
- Sporulation then occurs days to weeks after release into the environment.
- Ingestion of sporulated oocysts occurs and sporozoites are released that invade the intestinal epithelial cells.
- Sporozoites develop into trophozoites, which undergo schizogony and form merozoites.
- Merozoites may develop into macro- or microgametes, which become fertilized, resulting in oocysts.
- Entire life cycle is completed in the host.
- Incubation period is between 2 and 14 days, with an average of 7 days.
- Outbreaks have been associated with the consumption of raspberries, mesclun (young salad greens), salad mixes, cilantro, and basil.
- Infection occurs through the consumption of contaminated food and water.
- Transmission does not occur through person-to-person spread.
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