Cyclosporiasis (Cyclospora Infection)

About This Disease

Cyclospora cayetanensis is a small parasite that causes cyclosporiasis, an illness of the intestines.

Signs and Symptoms

The symptoms usually start about 1 week after a person is exposed to the parasite, but can range from 1-20 days. Symptoms last for about 10-24 days but can be longer in persons who are immunocompromised. The most common symptoms are watery diarrhea, loss of appetite, abdominal pain, nausea and sometimes vomiting.


People can get cyclosporiasis by ingesting contaminated water or food. Generally, cyclosporiasis is very rare in the United States, however, there have been some outbreaks in the United States linked to various types of imported fresh fruits and vegetables. It is not transmitted person-to-person since humans shed a non-infectious form of the parasite in their stool.



A doctor can perform a test of your stool for “ova and parasites”. Symptoms are similar to intestinal illness caused by some bacteria and viruses, so tests are needed to find the cause. Diagnosis can be difficult in part because even patients who are symptomatic might not shed enough oocysts in their stool to be readily detectable by laboratory examinations. Therefore, patients might need to submit several specimens collected on different days. Identification of the parasite requires special laboratory tests that are not routinely done when stool is tested for parasites. Therefore, if indicated, health care providers should specifically request testing for Cyclospora.


A doctor can prescribe an oral medicine that works for the majority of cases. Fluid and electrolyte replacement is also important for anyone experiencing diarrhea.  Most people who have healthy immune systems will recover without treatment. If not treated, the illness may last for a few days to a month or longer. Symptoms may seem to go away and then return one or more times (relapse). Anti-diarrheal medicine may help reduce diarrhea, but a health care provider should be consulted before such medicine is taken. People who are in poor health or who have weakened immune systems may be at higher risk for severe or prolonged illness.

Risk in Hawaii

No cases of cyclosporiasis have been identified in a Hawaii resident in the past 10 years. However, nationally there has been an increase in domestically acquired cyclosporiasis outbreaks identified from pre-packaged salad mix and vegetable trays at chain restaurants and convenience stores. The number of domestically acquired cases typically rises during the spring and summer, usually in May, June and July.


  • Do not drink water or eat food that could be contaminated with human or animal waste.
  • Do not drink untreated water (ponds, streams, rivers).
  • Boiling water can kill the parasite. Iodine and chlorine do not kill the parasite.
  • Avoid swimming while ill with diarrhea until 2 weeks after diarrhea resolves.
  • When traveling to the developing world, Avoid
    • Raw vegetables and salads and fruits that cannot be peeled
    • Drinks with ice, or ice cream
    • Food from street vendors
    • Tap water, instead of safe bottled water
    • Foods that are not thoroughly cooked and served hot.
    • Rinse all fruits and vegetables with running water before eating, cutting, or cooking.
    • Wash cutting boards thoroughly after contact with each food, so that the boards do not contaminate the next food prepared.

Information for Clinicians



Last reviewed August 2019