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Cyclospora is a parasite that causes diarrhea.
Cyclosporiasis is an intestinal infection caused by the parasite Cyclospora cayetanensis. People of any age are at risk of infection. People living in or traveling to developing countries may be at increased risk, but infection can be acquired worldwide. In the United States, most cases of Cyclospora infection are detected in the Spring and Summer.
Transmission can occur by eating food or drinking water contaminated with feces that contain Cyclospora.
Cyclospora needs time (days or weeks) to become infectious after being shed in feces (stool). Because Cyclospora takes so much time to become infectious, it is unlikely that Cyclospora is passed directly from one person to another. The primary source of the parasite is not yet known, and it is unknown whether animals can be infected and pass the infection on to people.
Symptoms to look for:
- Watery diarrhea
- Frequent, sometimes explosive bowel movements
- Extreme fatigue
- Loss of appetite
- Substantial weight loss
- Increased gas and bloating
- Stomach cramps, nausea, and vomiting
- Low-grade fever
Symptoms appear about 1 to 14 days (usually one week) after eating contaminated food or drinking contaminated water. Symptoms of cyclosporiasis may come and go and, if untreated, illness can last for a few days to a month or longer. Some infected people may not have symptoms.
Contact your healthcare provider if you have symptoms.
Laboratory tests are available to look for Cyclospora in stool.
Because many laboratories do not routinely check for Cyclospora in stool samples, your doctor must specifically request a Cyclospora test if cyclosporiasis is suspected.
Cyclosporiasis is treated with antibiotics.
Immunocompromised patients may need longer treatments with higher doses of antibiotics. People with severe or long-lasting diarrhea should call their doctor.
The risk of cyclosporiasis can be reduced.
- Wash fruits and vegetables before eating them.
- Cook foods to at least 158°F.
- Avoid drinking untreated water from lakes, streams, springs, or any other untreated sources.
- Avoid touching human or animal feces.
- Wash hands after using the toilet, after changing diapers, and before handling food or eating.
Revised July 2026
