Cyclosporiasis

Cyclosporiasis is a diarrheal illness caused by a parasite called Cyclospora, which only infects humans. The parasite is found in the intestine of an infected person and is passed in their feces (stool). Cyclospora is common in developing countries, in particular in tropical and subtropical countries where sewage and water treatment is poor.

People become infected with Cyclospora by eating food or drinking water contaminated with the parasite. In Canada, cyclosporiasis is seen most often in travellers to regions where the parasite is common, or from eating contaminated fruits or vegetables imported from these regions. Fresh fruit and vegetables can come in contact with water or soil contaminated by infected farm workers. People with cyclosporiasis pass immature parasites in their feces, which then develop in the environment (for example, in soil) into mature parasites, which can cause infection if ingested. Cyclospora cannot be spread by direct person-to-person contact. 

Symptoms usually start within 2 to 14 days after a person eats food or drinks water contaminated with the parasite. Most people experience some or all of the following symptoms:

• watery diarrhea
• nausea
• vomiting
• stomach cramps
• bloating and gas
• loss of appetite
• weight loss
• tiredness

The illness may be more severe in young children, older adults and people with weakened immune systems.

Some people may recover from cyclosporiasis on their own without treatment. However, without treatment, the illness can last for several weeks to months and symptoms may come and go. The infection responds well to antibiotic treatment, which is available from your health care provider, but even with treatment, it may take time for the gut to return to normal. Always drink plenty of liquids when having diarrhea and/or vomiting, to prevent dehydration.

Anyone who is infected with Cyclospora and has symptoms of diarrhea should stay at home. People whose work involves preparing or handling food, providing child care or health care, and children who attend daycare, should remain at home until the diarrhea has stopped for at least 24 hours.

To help prevent becoming ill with cyclosporiasis:

• Avoid local water when travelling to countries where the water supply is uncertain; use only sealed bottled water for drinking, brushing teeth, preparing foods, making ice and cooking. Cyclospora are destroyed by boiling or cooking, but may not be killed by chemicals such as chlorine used for treating water.
• Beware of raw foods washed in local water when travelling; eat only cooked food and fruit that can be peeled after it has been washed with water from a safe source.
• Rinsed produce can reduce, but may not always remove the parasite.
• Avoid swallowing water when swimming and do not drink untreated water from lakes and rivers.
• Always wash hands well with soap and water for at least 15 seconds before and after preparing food, before eating, after using the toilet, after changing diapers, after handling pets or their feces, and anytime hands may be dirty.

Ottawa Public Health (OPH) must be notified by health care providers and laboratories when a person is infected with cyclosporiasis. OPH conducts an investigation to determine the potential cause or source of the infection, provides education to the infected person and their close contacts, and follows up with the infected person’s health care provider, as needed.