Cyclospora cayetanensis

Brent Dixon

Identified as a coccidian protozoan parasite and named in early 1990’s. Humans are the only host for this species.

Cyclospora cyst 2Cyclospora cyst
Figure 1. Two images of Cyclospora oocysts (left: UV fluorescence microscopy; right: wet mount).

Life Cycle: Transmission stage (oocyst) is spherical and 8-10 µm in diameter. Unsporulated (immature) oocysts are shed into the environment with the faeces of infected individuals. Oocysts undergo sporulation, becoming mature and infectious within 7-15 days.

Cyclospora lifecycle
Figure 2. Cyclospora cayetanensis life cycle (Source: CDC).

Transmission: Early outbreaks were waterborne. Since mid-1990’s foodborne outbreaks have been reported annually in Canada and the U.S. Foodborne outbreaks mainly associated with the consumption of fresh imported produce, including raspberries, blackberries, mesclun, basil, snow peas.

Guatemalan raspeberries
Figure 3. Foodborne outbreaks are mainly associated with the consumption of fresh imported produce, such as raspberries.

Prevalence: Reported worldwide; endemic in Haiti, Peru, Guatemala, Nepal; 151 cases reported in Canada in 2008

Susceptible Populations: Immunocompromised persons, travellers

Symptoms: Diarrhea, loss of appetite, abdominal cramps, bloating, nausea, fatigue

Treatment: bactrim (sulfamethoxazole and trimethoprim) is the drug of choice

Control Measures: Good agricultural practices including use of filtered water in irrigation, mixing pesticides, processing, and washing hands and equipment; good worker hygiene (hand washing). Cyclospora is resistant to chemical disinfectants. At consumer/food handler level, good hygiene is important, washing of fruits and vegetables is recommended, when possible, cooking and freezing are effective in destroying Cyclospora.