Cyclospora cayetanensis infection causes prolonged, watery diarrhea lasting for 10-24 days in untreated, immunocompetent patients. The three important human intestinal protozoa (Cryptosporidium, Cyclospora, and Isospora) are resistant to chlorine disinfection and cause identical symptoms.
CASES/YEAR
16,264 (US); 325,280 (Global)
OTHER NAMES
Intestinal coccidial infections; Isospora belli (Related Infection); Sarcocystosis (Related Infection);
INCUBATION
About one week; Range of 1-11 days; [PPID, p. 3422]
INITIAL SYMPTOMS
Diarrhea lasting more than two weeks; Eosinophilia may be associated with the related Isospora and Sarcocystis infections.
PRECAUTIONS
Standard; See note J: "Use Contact Precautions for diapered or incontinent children <6 years of age for duration of illness." [CDC 2007 Guideline for Isolation Precautions] Person to person transmission is unlikely. Peruvian children shed organisms for an average of 23 days. [CCDM, p. 140]
COMMENTS
FINDINGS:
Cyclospora infections cause prolonged, watery diarrhea, fatigue, and weight loss. Fever is rare. Diarrhea usually lasts for 10-24 days in untreated, immunocompetent patients. Complications include Guillain-Barre syndrome and Reiter's syndrome. [CCDM, p. 139] "Does not cause fever, inflammatory diarrhea or eosinophilia." Associated with reactive arthritis in prolonged infections; [ABX Guide] Symptoms include noninflammatory diarrhea, fatigue, weight loss, abdominal pain, nausea, and sometimes constipation. The average incubation period is one week. Diagnosis by identification of oocysts in fecal smears is difficult and requires the skills of an experienced technician. [Soave R, Herwaldt BL, Relman DA. Cyclospora. Infect Dis Clin North Am. 1998 Mar;12(1):1-12] An outbreak of more than 400 cases linked to prepackaged lettuce from Mexico and sold to restaurants in Nebraska and Iowa occurred in June and July 2013. [CDC: Investigation of an Outbreak of Cyclosporiasis in the United States] Reported complications are biliary tract disease (AIDS patients), reactive arthritis, and Guillain-Barre syndrome. [PPID, p. 3422]
EPIDEMIOLOGY:
Outbreaks in North America have been linked to produce (raspberries, basil, and lettuce) imported from developing countries. [CCDM, p. 140]
RELATED INFECTIONS:
The three important human intestinal coccidial protozoa are Cryptosporidium, Cyclospora, and Isospora. They are resistant to chlorine disinfection and cause identical symptoms. The Cryptosporidium cysts are smaller and more difficult to remove by filtering. The cysts of Cyclospora and Isospora, unlike those of Cryptosporidium, are not infectious when passed in the feces. They require days to weeks in the environment to sporulate. Isospora is rarely found outside tropical and subtropical regions. Isospora, and possibly Dientamoeba fragilis, are the only protozoans known to cause eosinophilia. [Guerrant, p. 641-4, 940] Isospora belli was renamed Cystoisospora belli. Findings are fever, abdominal pain, and watery diarrhea (no blood), and eosinophilia. Chronic infection in AIDS patients may resemble cryptosporidiosis. [Harrison ID, p. 1121] Sarcocystosis is a similar disease caused by Sarcocystis spp. Most infections are asymptomatic, but gastroenteritis can occur. Humans are infected after eating poorly cooked beef or pork. In addition to diarrhea and abdominal pain, humans can also develop intramuscular cysts, myalgias, and eosinophilia. [Guerrant, p. 644-5]
DIAGNOSTIC
Microscopic detection of the Cyclospora 8-10 um oocysts; Lab techniques include a modified acid-fast stain, wet prep with phase contrast, and ultraviolet illumination; [CCDM] Request Cyclospora testing from lab; [CDC Travel]
SCOPE
Global; Tropical and subtropical regions; Summers in Nepal; North American outbreaks linked to imported fresh produce; [CDC Travel]
SIGNS & SYMPTOMS
-
>fatigue, weakness
-
>fever
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>myalgia
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G abdominal pain
-
G constipation
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G diarrhea
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G nausea, vomiting
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H eosinophilia
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*arthritis
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*paralysis
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*weight loss
ENTRY
Ingestion, Swimming
SOURCE
Fecally Contaminated Soil, Soil or Dust (Ingesting or Inhaling), Eating Contaminated Food, Eating Contaminated or Infected Meat, Eating Contaminated Produce, Waterborne (Ingesting, Inhaling, or Swimming)
RESERVOIR
Cattle, Goats and Sheep, Swine, Human
RISK FACTORS
- AIDS patients
- Ingest infectious agents in food/water
- Swim in contaminated water (ingestion or inhalation)
- Travel to endemic area
REFERENCES FOR CASES/YEAR
1. (US) Estimated 16,264 cases in 1997; [Mead1999: PMID 10511517]
2. (Global) Sarcocystosis prevalence rates of 10% to 23% have been reported in rural areas of Laos and Tibet; [Guerrant, p. 644] Estimate global cases/yr at 20 X US cases/yr;