Barbara L. Herwaldt
Cyclospora cayetanensis, a coccidian protozoan parasite.
Ingestion of infective Cyclospora oocysts, such as in contaminated food or water.
Most common in tropical and subtropical regions, where outbreaks are frequently seasonal (such as during summers and rainy season in Nepal); even short-term travelers can become infected. Outbreaks in the United States and Canada have been linked to imported fresh produce.
Incubation period averages 1 week (range, 2 days to ≥2 weeks). Onset of symptoms is often abrupt but can be gradual; some people have an influenzalike prodrome. The most common symptom is watery diarrhea, which can be profuse. Other symptoms can include anorexia, weight loss, abdominal cramps, bloating, nausea, body aches, vomiting, and low-grade fever. If untreated, the illness can last for several weeks or months, with a remitting-relapsing course.
Diagnosed by detecting Cyclospora oocysts or DNA in stool specimens. Stool examinations for ova and parasites usually do not include methods for detecting Cyclospora unless testing for this parasite is specifically requested. Diagnostic assistance for Cyclospora and other parasitic diseases is also available from CDC (www.cdc.gov/dpdx; 404-718-4745; email@example.com). Cyclosporiasis is a nationally notifiable disease.
Trimethoprim-sulfamethoxazole; no highly effective alternatives have been identified.
Food and water precautions (see Chapter 2, Food & Water Precautions); disinfection with chlorine or iodine is unlikely to be effective.
CDC website: www.cdc.gov/parasites/cyclosporiasis
- Abanyie F, Harvey RR, Harris JR, Wiegand RE, Gaul L, Desvignes-Kendrick M, et al. 2013 multistate outbreaks of Cyclospora cayetanensis infections associated with fresh produce: focus on the Texas investigations. Epidemiol Infect. 2015 Dec;143(16):3451–8.
- Cama VA, Mathison BA. Infections by intestinal occidian and Giardia duodenalis. Clin Lab Med. 2015 Jun;35(2):423–44.
- Hall RL, Jones JL, Herwaldt BL. Surveillance for laboratory-confirmed sporadic cases of cyclosporiasis—United States, 1997–2008. MMWR Surveill Summ. 2011 Apr 8;60(2):1–11.
- Herwaldt BL. Cyclospora cayetanensis: a review, focusing on the outbreaks of cyclosporiasis in the 1990s. Clin Infect Dis. 2000 Oct;31(4):1040–57.
- Marques DFP, Alexander CL, Chalmers RM, Chiodini P, Elson R, Freedman J, et al. Cyclosporiasis in travelers returning to the United Kingdom from Mexico in summer 2017: lessons from the recent past to inform the future. Euro Surveill. 2017 Aug 3;22(32). Pii: 30592.
- Ortega YR, Sanchez R. Update on Cyclospora cayetanensis, a food-borne and waterborne parasite. Clin Microbiol Rev. 2010 Jan;23(1):218–34.