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Cyclosporiasis

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Reporting Obligations

Confirmed and suspected cases shall be reported to the local Health Unit.

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Epidemiology

Aetiologic Agent

Cyclospora cayetanensis is a coccidian protozoan; oocysts (rather than cysts) are passed in stools and become infectious days to weeks following excretion.

Clinical Presentation

Watery diarrhea is the most common symptom and can be profuse and protracted. Anorexia, nausea, vomiting, substantial weight loss, flatulence, abdominal cramping, myalgia, and prolonged fatigue also can occur. Fever is rare. Infection usually is self-limited, but untreated people may have remitting, relapsing symptoms for weeks to months. Individuals who are not treated may develop chronic complications including Guillain-Barré syndrome or Reiter’s syndrome. Biliary tract disease also has been reported.

Asymptomatic infection has been documented most commonly in settings where cyclosporiasis is endemic.

Modes of Transmission

Both foodborne and waterborne outbreaks have been reported. Most of the outbreaks in the United States and Canada have been associated with consumption of imported fresh produce. Imported fresh fruits and vegetables, including basil, cilantro, raspberries, blackberries, mesclun lettuce, snow and snap peas, and pre-packaged salad mixes have been linked as sources of Cyclospora infection in Canada. Cyclospora is not naturally found in or on fresh fruits and vegetables, or any other foods. However, it is suspected that food contamination occurs during cultivation, harvest, packaging or transportation through contact with contaminated water or infected workers.

Direct person-to-person transmission is unlikely, as excreted oocysts take days to weeks under favorable environmental conditions to sporulate and become infective. The oocysts are resistant to most disinfectants used in food and water processing and can remain viable for prolonged periods in cool, moist environments.

Incubation Period

Incubation period is approximately 7 days and ranges from 2–14 days.

Period of Communicability

Direct person-to-person transmission is unlikely. Low-level shedding of oocysts is common, even in persons who are symptomatic. Excreted oocysts take days to weeks under favorable environmental conditions to sporulate and become infective.

Risk Factors/Susceptibility

Immunocompromised individuals appear more susceptible to infection; diarrhea can last for months in some patients. If you have already had cyclosporiasis, you can get it after recovery if you are exposed to the parasite again.

Diagnosis and Laboratory Testing

Diagnosis by demonstration of Cyclospora cayetanensis oocysts (by morphologic criteria) or Cyclospora deoxyribonucleic acid (DNA), by polymerase chain reaction (PCR) from an appropriate clinical specimen (e.g., stool, duodenal/jejuna aspirate, small bowel biopsy).

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Treatment and Case Management

The disease is not endemic in Canada; therefore, cases should be investigated as most likely associated with imported food or travel. Treatment is under the direction of the attending health care provider.

Exclude symptomatic food handlers, health care providers, and day care staff and attendees until symptom free for 24 hours, OR symptom free for 48 hours after discontinuing use of anti-diarrheal medication. The rationale for exclusion for 48 hours after discontinuing the use of anti-diarrheal medication is to ensure that diarrhea does not return after the anti-diarrheal medication has been discontinued. In the event that antibiotics are used, the person should be excluded until symptom free for 24 hours.

Provide education about the illness, hand hygiene, safe food handling and on preventing the spread of infection. This includes washing hands after using sanitary facilities and before handling food; washing fresh fruits and vegetables; avoiding foods from questionable sources such as roadside vendors when travelling and avoiding consumption of surface water without prior treatment.

Patient Information

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Additional Resources

Public Health Ontario. “Cyclosporiasis.”

Government of Canada. “For health professionals: Cyclosporiasis (Cyclospora).”

References

Ministry of Health and Long-Term Care, Infectious Diseases Protocol, 2019.