Cyclosporiasis

Reporting Obligations

Suspected cases must be reported immediately by phone to the Thunder Bay District Health Unit at 625-8318 or toll-free 1-888-294-6630, ext. 8318 (Monday-Friday, 8:30 am to 4:30 pm). After hours and on weekends/holidays call Nurses Registry Thunder Bay at (807) 624-1280.

 

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. Low-grade fever occurs in approximately 50% of patients. Biliary tract disease also has been reported. Infection usually is self-limited, but untreated people may have remitting, relapsing symptoms for weeks to months. 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 including Guatemalan raspberries and Thai basil. Investigations done by the Canadian Food Inspection Agency in the early 2000’s indicated that fresh fruits and vegetables (berries, basil and mesclun lettuce) were sources of Cyclospora infection. 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 to 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

  • Consumption of fresh herbs, berries, raw produce, potentially contaminated water
  • Recreational water contact
  • Travel outside the province in seven days preceding illness

 

Diagnosis & 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)

Testing Information & Requisition

 

Treatment & Case Management

Treatment is under the direction of the attending health care provider.

Exclude symptomatic food handlers, healthcare 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

Patient Fact Sheet

 

Additional Resources

1. CDC. “Parasites—Cyclosporiasis”.

 

References

1. Ministry of Health and Long Term Care, Infectious Diseases Protocol, 2016.  Appendix A (2014) and Appendix B (2014)

Last Updated: 26/10/2017