Cyclospora cayetanensis is a single-celled parasite that cannot be seen without the aid of a microscope. The first known human cases of Cyclospora infection (that is, cyclosporiasis) were reported in 1979. Cases began being reported more often in the mid-1980’s and in the last several years, outbreaks of cyclosporiasis have been reported in the United States and Canada.

How is Cyclospora spread?

Transmission of Cyclospora occurs by the fecal-oral route. That means people can acquire Cyclospora by ingesting something, for example water or food, that was contaminated with infected stool. When excreted, Cyclospora is not infectious and may require from days to weeks in the environment to become infectious. Therefore, transmission of Cyclospora directly from an infected person to someone else is unlikely. It is unknown whether animals can be infected and pass infection to people.

Who is at risk for Cyclospora infection?

People of all ages are at risk for infection. In the past, Cyclospora infection was usually found in people who lived or traveled in developing countries. However now that many foods are imported, everyone can be at risk. Because the parasite is not infective immediately, it is very hard to determine where a person might have been exposed. In Canada, outbreaks have been traced to consumption of imported strawberries and raspberries.

What are the symptoms of infection?

The time between becoming infected and becoming sick is usually about one week. Cyclospora infects the small intestine (bowel) and usually causes watery diarrhea, with frequent, sometimes explosive, bowel movements. Infection is usually self-limited. Other symptoms can include loss of appetite, substantial loss of weight, bloating, increased gas, stomach cramps, nausea, vomiting, muscle aches, low-grade fever, and fatigue. Symptoms may seem to go away and then return one or more times, particularly, among the untreated. If not treated, the illness may last from a few days to a month or longer. Some people who are infected with Cyclospora do not have any symptoms.

How is Cyclospora infection diagnosed?

Your physician will ask you to submit stool specimens to see if you are infected. Because testing for Cyclospora infection can be difficult, you may be asked to submit several stool specimens over several days. Your physician may also have your stool checked for other organisms that can cause similar symptoms.

How is infection treated?

The recommended treatment for infection with Cyclospora is trimethoprim-sulfamethoxazole that may be prescribed by your physician. People who have diarrhea should rest and drink plenty of fluids.

How is infection prevented?

Avoiding water or food that may be contaminated with stool may help prevent Cyclospora infection. Washing fresh produce thoroughly before it is eaten is also recommended. People who have previously been infected with Cyclospora can become infected again.

Information adapted from: