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  • A protozoan infection that is caused by cyclospora cayetanensis, which is most commonly acquired from contaminated food or water, and which is characterized by watery diarrhea and abdominal pain.
  • Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis.
  • People can become infected with Cyclospora by consuming food or water contaminated with the parasite.
  • People living or traveling in countries where cyclosporiasis is endemic may be at increased risk for infection.
  • People become infected with Cyclospora by ingesting sporulated oocysts, which are the infective form of the parasite.
  • This most commonly occurs when food or water contaminated with feces is consumed.
  • An infected person sheds unsporulated (immature, non-infective) Cyclospora oocysts in the feces.
Cyclospora Life Cycle
Cyclospora Life Cycle

Geographic Distribution

  • Cyclosporiasis occurs in many countries, but it seems to be most common in tropical and subtropical regions. In areas where cyclosporiasis has been studied, the risk for infection is seasonal. However, no consistent pattern has been identified regarding the time of year or the environmental conditions, such as temperature or rainfall.
  • In the United States, foodborne outbreaks of cyclosporiasis have been linked to various types of imported fresh produce, such as raspberries, basil, snow peas, mesclun lettuce, and cilantro; no commercially frozen or canned produce has been implicated to date.
  • U.S. cases of infection also have occurred in persons who traveled to Cyclospora-endemic areas. To reduce the risk for infection, travelers should take precautions, such as those recommended in CDC’s Health Information for International Travel (Yellow Book). Travelers should be aware that treatment of water or food by routine chemical disinfection or sanitizing methods is unlikely to kill Cyclospora oocysts.

Causal Agents

Cyclospora cayetanensis is a coccidian protozoan. It appears that all human cases are caused by this species; no animal reservoirs for C. cayetanensis have been identified.

Life Cycle

  • When freshly passed in stools, the oocyst is not infective image (thus, direct fecal-oral transmission cannot occur; this differentiates Cyclospora from another important coccidian parasite, Cryptosporidium).
  • In the environment image , sporulation occurs after days or weeks at temperatures between 22°C to 32°C, resulting in division of the sporont into two sporocysts, each containing two elongate sporozoites.
  • The sporulated oocysts can contaminate fresh produce and water image which are then ingested.
  • The oocysts excyst in the gastrointestinal tract, freeing the sporozoites, which invade the epithelial cells of the small intestine,
  • Inside the cells they undergo asexual multiplication into type I and type II meronts.
  • Merozoites from type I meronts likely remain in the asexual cycle, while merozoites from type II meronts undergo sexual development into macrogametocytes and microgametocytes upon invasion of another host cell.
  • Fertilization occurs, and the zygote develops to an oocyst which is released from the host cell and shed in the stool.
  • Several aspects of intracellular replication and development are still unknown, and the potential mechanisms of contamination of food and water are still under investigation.
States Reporting Cyclospora Infections
States Reporting Cyclospora Infections


  • Cyclospora is spread by people ingesting something—such as food or water—that was contaminated with feces (stool).
  • Cyclospora needs time (typically, at least 1–2 weeks) after being passed in a bowel movement to become infectious for another person.

Risk factors

  • People living or traveling in tropical or subtropical regions of the world may be at increased risk for infection because cyclosporiasis is endemic (found) in some countries in these zones.
  • In the United States, foodborne outbreaks of cyclosporiasis have been linked to various types of imported fresh produce.
  • People can get infected with Cyclospora more than once.


  • The time between becoming infected and becoming sick is usually about 1 week.
  • Cyclospora infects the small intestine (bowel) and usually causes watery diarrhea, with frequent, sometimes explosive, bowel movements.
  • Other common symptoms include loss of appetite, weight loss, stomach cramps/pain, bloating, increased gas, nausea, and fatigue. Vomiting, body aches, headache, fever, and other flu-like symptoms may be noted. Some people who are infected with Cyclospora do not have any symptoms.


  • Your health care provider will ask you to submit stool specimens to see if you are infected.
  • You might be asked to submit more than one specimen from different days.
  • Identification of this parasite in stool requires special laboratory tests that are not routinely done.
  • Therefore, if indicated, your health care provider should specifically request testing for Cyclospora.
  • In addition, your health care provider might have your stool checked for other organisms that can cause similar symptoms.


  • The recommended treatment is a combination of two antibiotics, trimethoprim-sulfamethoxazole, also known as Bactrim*, Septra*, or Cotrim*.
  • People who have diarrhea should also rest and drink plenty of fluids.
  • Cyclospora cayetanensis
    Cyclospora cayetanensis


Avoiding food or water that might have been contaminated with stool may help prevent Cyclospora infection. Consumers and retailers should always follow safe fruit and vegetable handling recommendations:

  • Wash: Wash hands with soap and warm water before and after handling or preparing fruits and vegetables. Wash cutting boards, dishes, utensils, and counter tops with soap and hot water between the preparation of raw meat, poultry, and seafood products and the preparation of fruits and vegetables that will not be cooked.
  • Prepare: Wash all fruits and vegetables thoroughly under running water before eating, cutting, or cooking. Fruits and vegetables that are labeled “prewashed” do not need to be washed again at home. Scrub firm fruits and vegetables, such as melons and cucumbers, with a clean produce brush. Cut away any damaged or bruised areas on fruits and vegetables before preparing and eating.
  • Store: Refrigerate cut, peeled, or cooked fruits and vegetables as soon as possible, or within 2 hours. Store fruits and vegetables away from raw meat, poultry, and seafood.

External links


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