Cyclosporiasis is an intestinal infection caused by Cyclospora, a microscopic parasite that people swallow in contaminated food or water. It can cause frequent, watery diarrhea that usually starts about a week after exposure and, without treatment, can last for weeks or even months.
Cases usually rise in Québec between May and August. In 2026, more cases were reported than during the same period the previous year. This guide covers how to recognize the infection, how people catch it, when to get care, and how it is diagnosed, treated and prevented.
Key takeaways
- Cyclospora is a microscopic parasite. The infection it causes is called cyclosporiasis.
- Symptoms usually begin about one week after exposure, with a range of 2 to 14 days, and can include frequent or profuse watery diarrhea.
- People catch it by swallowing contaminated food or water. Direct spread from one person to another is unlikely.
- In Québec’s 2026 season, most infections were acquired during travel, especially to Mexico, or from contaminated imported fresh produce or herbs.
- Diagnosis usually requires a stool test. The first-line prescription treatment in Canada is trimethoprim-sulfamethoxazole (TMP-SMX).
- If watery diarrhea persists, contact Bina Medical Clinic or call Info-Santé 811.
What is cyclospora?
Cyclospora is a microscopic parasite that infects the intestine. The illness it causes is called cyclosporiasis. A person becomes infected by swallowing food or water that contains the parasite.
Having had cyclosporiasis before does not protect you. The infection does not leave lasting immunity, so a person can catch it again.
What are the symptoms of cyclospora?
Cyclospora symptoms can include frequent or profuse watery diarrhea, cramps, bloating and fatigue, but some infected people have no symptoms at all.
When symptoms appear, they may include:
- Frequent or profuse watery diarrhea.
- Abdominal cramps or pain.
- Bloating and gas.
- Nausea and sometimes vomiting.
- Loss of appetite and weight loss.
- Marked fatigue.
- Mild fever.
How soon after exposure do symptoms start?
Symptoms usually appear about one week after exposure, although the delay can be anywhere from 2 to 14 days. So the food or water responsible was often consumed a week or two before you felt sick, not the day before.
How long does cyclospora last?
Without treatment, cyclospora symptoms can last for several weeks or even months. Symptoms can also improve for a few days and then return, which can make the illness seem to have cleared when it hasn’t. Once prescription treatment starts, symptoms often begin to improve within 2 to 3 days.
How do you get cyclospora?
You get cyclospora by swallowing food or water contaminated with the parasite. The risk of infection is higher for people who travel to tropical or subtropical regions and drink untreated water or eat raw local produce.
Is cyclospora contagious?
Direct spread of cyclospora from one person to another is unlikely. When the parasite leaves the body in stool, it is not immediately infectious. It usually needs 7 to 15 days in the environment before it can infect someone.
Who may have a longer or more severe illness?
Young children, older adults and people with a weakened immune system may develop a longer or more severe illness.
Why are cyclospora cases up in Québec in 2026?
The Québec government’s update of July 30, 2026 reported more cyclosporiasis cases since its investigation began on May 1 than during the same period the previous year. Cases in Québec usually rise between May and August.
- Where people were infected: In the 2026 season, mainly during travel, especially to Mexico, or by eating contaminated fresh fruit, vegetables or herbs imported from countries where the parasite is more common.
- Common source: At the time of the update, public-health authorities were investigating whether cases shared a common source.
- Link to the US outbreak: As of the July 30 update, no Québec cases were believed to be linked to the outbreak happening at the same time in the United States.
- Is imported produce unsafe? Not all of it. The Québec update did not name a specific product for everyone to avoid. For advice on a specific product, follow official food-recall notices.
When should you see a doctor for cyclospora symptoms?
Contact Bina Medical Clinic or call Info-Santé 811 if you have persistent watery diarrhea. This is especially important if you:
- Recently travelled, especially to Mexico or another tropical or subtropical region.
- Ate raw imported fruit, vegetables, leafy greens or fresh herbs.
- Are a young child, an older adult, pregnant, immunocompromised, or living with a significant chronic illness.
- Cannot maintain normal hydration.
Seek same-day medical advice
- Diarrhea continues beyond 48 hours despite rehydration.
- Fever with diarrhea lasts more than 48 hours.
- Diarrhea lasts longer than one week.
Go to an emergency department
Seek emergency care for signs of severe dehydration or deterioration, including:
- Extreme thirst with no urination for 12 hours.
- Inability to keep fluids down.
- Confusion.
- Severe abdominal pain.
- A large amount of blood in the stool.
- Black stool.
How is cyclospora diagnosed?
Diagnosing cyclospora usually requires a stool test that looks for the parasite. The parasite is not always present in every sample, so you may be asked for several stool specimens collected on different days.
Tell your healthcare professional about any recent travel and the foods you ate. This information can help guide testing and support the public-health investigation.
How is cyclospora treated in Canada?
The first-line treatment for cyclospora in Canada is a prescription antibiotic, trimethoprim-sulfamethoxazole (TMP-SMX). Symptoms often start to improve within 2 to 3 days of starting treatment, although intestinal symptoms can take longer to settle.
While you recover:
- Stay hydrated. Drink water or an oral rehydration solution to replace lost fluids and mineral salts.
- Don’t self-treat. Do not start antibiotics on your own or use leftover ones.
- Ask for individual advice if you have a sulfa allergy, a weakened immune system, are pregnant, or don’t improve after treatment.
How can you prevent cyclospora?
Washing produce lowers many food-safety risks but may not remove Cyclospora completely. Combine it with the other steps below.
At home in Québec
- Rinse fruit and vegetables under running water before eating, cutting, peeling or cooking them.
- During the seasonal rise in cases, choose fresh produce grown in Québec or elsewhere in Canada when practical.
- Consider cooking produce imported from places where Cyclospora is common.
- Wash your hands and follow safe food-handling practices.
- Check official Québec and Canadian food-recall notices. Do not eat, serve or sell a recalled product.
When travelling to a higher-risk region, such as Mexico
- Drink water from a safe source, such as sealed bottled water.
- Choose food that is thoroughly cooked and served hot.
- Eat fruit you peel yourself.
- Avoid raw foods that may have been washed in local untreated water.
Is cyclosporiasis a reportable disease in Québec?
Yes. Cyclosporiasis is a reportable disease in Québec and across Canada. Healthcare professionals and laboratories report confirmed cases to public-health authorities. If public health contacts you after a diagnosis, accurate details about your travel and what you ate help them find a common source and prevent more people from getting sick.
Concerned about cyclospora? Talk with us
If you have prolonged watery diarrhea or are worried about a recent exposure, contact Bina Medical Clinic in Brossard. When you reach us, mention any recent travel and the fresh foods or herbs you ate in the two weeks before your symptoms began.
Related: Results Follow-Up consultation
Official sources
- Gouvernement du Québec: Cyclosporiasis (update of July 30, 2026)
- Public Health Agency of Canada: Cyclosporiasis (Cyclospora)
- Public Health Agency of Canada: Cyclosporiasis surveillance
- Recalls and safety alerts: Government of Canada
This information is for education only and does not replace individualized medical advice, diagnosis or treatment. Public-health information can change as an investigation progresses.
