Cyclospora cayetanensis

Valeria Fabre, M.D., Paul G. Auwaerter, M.D.


  • Single-celled coccidian parasite
  • Member of family Eimeriidae, subclass Coccidiasina, subphylum Apicomplexa.
    • Humans appear to be only known to have C. cayetanensis (no animal reservoirs have been identified).
    • Infected persons shed unsporulated (non-infective) oocysts in feces.
      • It takes ~1-2 weeks for oocysts to sporulate and become infective (therefore person-to-person transmission less likely).
    • Other members (13) of Cyclospora found in animals including rodents, vipers.
    • Cysts are 7.7-9.9 µm in diameter in stool appears as a sphere with morulae within [Fig 1].
    • Autofluorescent under ultraviolet microscopy.
  • It can be responsible for water- or food-borne outbreaks.
  • Routine chemical disinfection or sanitizing methods of food and water don’t generally kill Cyclospora oocysts.

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Last updated: March 8, 2020