Time to Think About Cyclosporiasis

Alan D. Dowell; Barbara Herwaldt, MD, MPH


July 28, 2014

Editorial Collaboration

Medscape &

Mr. Dowell: Are there other factors that can make it difficult to diagnose cyclosporiasis?

Dr. Herwaldt: Diagnosing cyclosporiasis can be difficult, in part because even persons who have profuse diarrhea might not shed enough Cyclospora parasites in their stool to be readily detectable by laboratory examinations. Several stool specimens, collected on different days, may need to be examined. CDC and other reference laboratories can provide diagnostic assistance and confirmatory testing, using microscopic and molecular techniques. No serologic tests are available for cyclosporiasis.

Mr. Dowell: How is cyclosporiasis treated? Are the medications different from those used to treat intestinal infections caused by other protozoan parasites?

Dr. Herwaldt: The treatment of choice for cyclosporiasis is trimethoprim/sulfamethoxazole (TMP/SMX). The typical regimen for immunocompetent adults is 1 double-strength tablet twice daily for 7-10 days. No highly effective alternatives have been identified yet for persons who are allergic to or cannot tolerate TMP/SMX. For example, drugs such as metronidazole, tinidazole, paromomycin, and iodoquinol are not effective against Cyclospora, and minimal data on nitazoxanide in this context are available.

The fact that the therapy for cyclosporiasis (TMP/SMX) differs from the medications used for most other intestinal parasitic infections, such as amebiasis, giardiasis, and cryptosporidiosis, highlights the importance of diagnosing the infection rather than treating empirically.

Mr. Dowell: How should healthcare providers advise their patients to prevent cyclosporiasis?

Dr. Herwaldt: The best-known way to prevent cyclosporiasis is by avoiding food or water that may be contaminated with feces. As always, fresh produce should be thoroughly washed before it is eaten, which should reduce (but might not eliminate) the risk for infection. Persons who are planning to travel to the tropics or subtropics should be told that food and water precautions for Cyclospora are similar to those for other intestinal pathogens, except that Cyclospora is unlikely to be killed by routine chemical disinfection or sanitizing methods, such as with chlorine or iodine. No vaccine for cyclosporiasis is available.

Mr. Dowell: Is cyclosporiasis a reportable disease?

Dr. Herwaldt: Yes; you should report suspected and confirmed cases of cyclosporiasis to local public health officials, who in turn are encouraged to notify CDC. CDC conducts national-level surveillance for cyclosporiasis to facilitate detection, investigation, and prevention of US cases and outbreaks. Although no molecular tools are available yet that can distinguish different strains of the parasite, development of such tools is a high priority for CDC and other agencies. The availability of DNA fingerprinting methods in the future could help public health investigators more quickly determine whether cases of cyclosporiasis are linked to each other and to particular food items and sources.

Visit CDC's Cyclosporiasis Website for more information, including resources for health professionals and the general public.