Symptoms and Signs of Cyclospora Infection (Cyclosporiasis)

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Medically Reviewed on 3/11/2019

Doctor's Notes on Cyclospora Infection (Cyclosporiasis)

Cyclospora cayetanensis is a single cell microscopic parasite that causes cyclosporiasis, an infection of human intestinal tract cells; it mainly occurs in semitropical and tropical regions. Signs and symptoms of a Cyclospora infection is watery diarrhea (sometimes termed explosive diarrhea), gas production, bloating, cramping, abdominal discomfort and/or pain, nausea, loss of appetite and weight, fatigue and flu-like symptoms; some individuals develop low fevers and vomiting. If not treated, the symptoms may last for weeks to months.

Cyclospora cayetanensis is the cause of cyclosporiasis; the parasite has a complicated life cycle that needs to develop (oocysts) in human intestinal cells; after development, the non-sporulated oocysts are shed in human feces into the environment where they mature (sporulate) and contaminate food and water sources where they can start their life cycle again by infecting humans.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.