GI IMPACT Study

The Diarrhea Study

Cyclospora - Information for Clinicians


Type of infection

Cyclospora cayetanensis is a protozoal parasite.

Sources of infection

  1. Cyclospora are found worldwide. Humans are the only known host; the role of animals is uncertain. Oocysts excreted in the stool of an infected person unsporulate in the environment and enter the food chain.
  2. Most infections occur in tropical and subtropical locations.
  3. Foodborne outbreaks have been linked to raspberries, basil, snow peas, and lettuce.
  4. Waterborne disease is thought to be important.
  5. Oocysts in water may not be killed by routine treatment with chlorine or iodine.

Usual symptoms

  1. Median incubation period is 7 days (range 2 to >14 days).
  2. Symptoms include watery diarrhea, anorexia, nausea, bloating, low grade fever, and increased gas.
  3. Fatigue and weight loss can be prominent.

Complications

  1. Malabsorption and Reiter's syndrome have been reported.

Duration of illness

  1. Symptoms can last a few days to more than a month. The course can be relapsing and remitting.

How is it treated?

  1. Because of the typical prolonged course, treatment is usually indicated.
  2. Trimethoprim sulfamethoxazole is the treatment of choice 5 mg/kg po or IV bid (trimethoprim component) up to 160 mg po bid for 7-10 days. Immunocompromised patients may require longer therapy.
  3. There is no clear alternative agent. Ciprofloxacin may have some activity.

Comments

  1. Rarely diagnosed on routine ova and parasite exam unless the microscopist is highly experienced as the organism does not stain with routine stains. Modified acid fast stains improve detection.
  2. Molecular assays may be more sensitive than microscopy.
  3. Travelers should take care to avoid food or water likely to be contaminated with human feces.

Resources

  1. Red Book
  2. CDC
  3. Ortega. Update on Cyclospora cayatensis, a food-borne and waterborne parasite. Clin Microbiol Rev 2010;23(1):218-34.