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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