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Cyclospora Infection

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Cyclospora infection (cyclosporiasis) facts

  • Cyclospora is a small parasitic organism. It is passed to humans when they ingest food contaminated with feces from an infected person.
  • It is most common in tropical countries, and imported foods such as lettuce have caused outbreaks in the United States. Travelers to tropical or subtropical countries are at risk, although the risk is relatively low.
  • Diarrhea is the most common symptom, often accompanied by cramping abdominal pain and fatigue. If left untreated, the diarrhea can last for several weeks.
  • The recommended treatment is a seven- to ten-day course of oral trimethoprim-sulfamethoxazole (Bactrim, Septra, Cotrim).
  • Complications are uncommon, but it is important for patients to drink lots of fluids to prevent dehydration.
  • Prevention efforts are focused on improving the safety of the food supply. Cyclospora requires a period of time outside the body to become infectious. The organism is not spread directly from person to person.

What is a Cyclospora infection?

Cyclospora infection is a diarrheal illness that occurs when humans accidentally ingest the Cyclospora parasite. This happens by eating or drinking items contaminated with soil or water.

What causes a Cyclospora infection?

Cyclospora cayetanensis is a parasite that cycles between the environment (soil) and humans during its life cycle. It survives for long periods of time in nature as an oocyst. The oocyst can resist extreme temperatures and the usual levels of chlorine in treated water. When temperatures warm, the oocyst matures and produces the infectious form, called sporozoites. When sporozoites are ingested by a human, they multiply in the gut and form new oocysts. These are excreted in feces, starting the cycle all over again.

What are the risk factors for a Cyclospora infection?

Cyclospora causes disease throughout the world, but it is commonest in tropical and subtropical climates. Outbreaks in cooler areas are often caused by food imported from warmer climates. Food is at risk if exposed to soil or water that is contaminated with human feces. Produce like lettuce, raspberries, basil, and snow peas have caused past outbreaks. In 2013, an outbreak involved many states, including Texas, Iowa, and Nebraska. It affected hundreds of people and was at least partially caused by bagged lettuce grown in Mexico. There have been small outbreaks in 31 states with a total of 546 people diagnosed with the infection in 2015.

Although travel to a tropical or subtropical country is a risk factor for Cyclospora infection, the risk is relatively low. Cyclospora is not a major cause of travelers' diarrhea.

Is Cyclospora contagious? What is the contagious period for Cyclospora?

Cyclospora is not contagious directly from person to person. Even though the oocysts are shed in stool, they take days to weeks to mature in the environment before becoming infectious. People can only be infected by eating or drinking something contaminated with mature oocysts.

Medically Reviewed by a Doctor on 9/23/2016


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