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Fact Sheet: Cyclospora


What is Cyclospora?

Cyclospora is a parasite that is composed of only one cell. It is too small to be seen with the naked eye (only 8-10 microns in diameter). Its full name is Cyclospora cayetanensis. It used to be called such names as cyanobacterium-like, coccidian-like, and Cyclospora-like bodies (CLBs).

The first known cases of Cyclospora infection (cyclosporiasis) were diagnosed in 1977. Cases have been reported more often since the mid-1980s, in part because we have better techniques for detecting the parasite in feces (bowel movements). Because Cyclospora is a newly recognized parasite, many questions remain about its biology, the ways it is spread, and the illness it causes.

How is Cyclosporosis transmitted?

Cyclospora parasites are transmitted by a person eating or drinking something that was contaminated with infected feces. We do not know how foods might get contaminated with Cyclospora, nor do we know if animals carry it.

Additional information:

In contrast to many other organisms, Cyclospora parasites are not infectious at the time they are passed in the feces of an infected person. In fact, the parasite does not become infectious until days to weeks later. Therefore, transmission of Cyclospora directly from an infected person to someone else is unlikely. However, Cyclospora parasites might be spread if feces from an infected person contaminates something else (e.g., water) which someone else might ingest after the parasite has had time to become infectious.

Who can get Cyclospora infection?

Persons of all ages can get Cyclosporosis. Although travelers to tropical countries may be at increased risk, people can get infected in the United States and Canada. Some evidence suggests that infection is most common in spring and summer. Investigation of an outbreak in the eastern United States and Ontario, Canada in 1996, indicated an association between eating Guatemalan raspberries and Cyclospora.

What are the symptoms of infection?

Cyclospora infects the small intestine (bowel) and usually causes watery diarrhea, with an average of about 6 to 7 stools per day. Other symptoms can include loss of appetite, weight loss, bloating, increased flatus (gas), stomach cramps, nausea, vomiting, tiredness, muscle aches, and low-grade fever. Some persons notice flu-like symptoms before they notice cramps or diarrhea. Other germs can cause illness that is very similar to that caused by Cyclospora. Some persons infected with Cyclospora do not develop any symptoms.

The length of time between becoming infected and developing symptoms probably averages at least several days and quite commonly is about a week. However, both shorter and longer intervals have been reported. If not treated, the illness may last for a few days to a month or longer and may come back (relapse) one or more times. We do not know yet whether persons with compromised immune systems, such as persons who have AIDS, tend to develop more severe illness if infected with Cyclospora.

What should you do if you think you may be infected?

If you think you may be infected with Cyclospora, you should consult your physician. Identification of this parasite requires special kinds of laboratory techniques that are not routinely used (for example, examination of an acid fast-stained slide of the feces). Therefore, your physician should specifically request testing for this parasite. More than one stool sample may need to be checked to find the parasite. Your physician may also want to have your feces checked for other causes of diarrhea.

How is infection treated?

Infection with Cyclospora is treatable with a combination of two antibiotics (trimethoprim-sulfamethoxazole). Infected persons who have diarrhea should rest and drink plenty of fluids. They should seek their physician's advice before taking a medication to slow their diarrhea.

How is infection prevented?

Based on what we know about how Cyclospora infection is spread, avoiding water or food that may be contaminated with fecal material is the best way to prevent infection. Since Cyclospora parasites are passed in fees, the best way to prevent Cyclospora from spreading is to wash your hands thoroughly after using the restroom. Persons who have previously been infected with Cyclospora can become infected again.

Issued by: The Oregon Health Services
Date: April, 1997 Return to top