NOTICE: Locally-acquired cyclosporiasis

TO: Health Care Providers

FROM:  Infectious Disease program on behalf of Public Health Ontario

REFERENCE:  Locally-Acquired Cyclosporiasis

DATE:  August 12, 2019

Current situation

Ontario is experiencing an increase in the number of Cyclospora infections. There have been 113 locally-acquired cyclosporiasis cases reported in the province between April 1 and August 6, 2019. We are requesting your assistance with the diagnosis of infected patients. Testing for Cyclospora will support prompt treatment of patients to lessen the duration of symptoms, as well as assist with identifying the source of illness.

• Diagnosis: Cyclospora infection can be diagnosed by submitting a stool sample for ova and parasite (O&P) testing to your local laboratory or to the Public Health Ontario Laboratory using the General Test Requisition form
• Treatment:  First-line treatment is trimethoprim-sulfamethoxazole (TMP-SMX).

What is cyclosporiasis?

Cyclosporiasis is a gastrointestinal illness caused by infection with the parasite Cyclospora cayetanensis. It is commonly characterized by frequent watery diarrhea, as well as other symptoms such as anorexia, fatigue, abdominal cramps, nausea, and myalgia. Left untreated, symptoms typically last 6 to 7 weeks and can wax and wane in intensity. Symptoms generally improve within 2 to 3 days of starting the first-line treatment for cyclosporiasis.

How is Cyclospora infection acquired?

People are infected by ingesting food or water contaminated with the parasite. Cyclospora is not endemic in Canada. Most reported cases in Ontario are infected when visiting an endemic country (e.g., in the Caribbean, South and Central America, South and South East Asia) or during annual spring/summer outbreaks of cyclosporiasis. When cases occur in individuals who did not travel (as is currently occurring in Ontario), an investigation is launched to determine potential sources of Cyclospora in imported foods. Most outbreaks of locally-acquired infections are likely due to fresh produce such as berries or herbs that are imported from Cyclospora endemic countries. The infection is unlikely to spread from person to person.

Additional Resources on Cyclosporiasis

For more details on Cyclospora infection, see:

For more information on cyclosporiasis in Ontario, including links to testing information, see: 

For further information please contact Infectious Disease program at 1-888-505-6074 or 905-688-8248 ext. 7330.