Cyclospora Parasite Outbreak Linked to ‘Explosive Diarrhoea’ Sickens More Than 1,000 in the US

July 10, 2026 Team Contributor

A growing Cyclospora infection outbreak in the United States has sickened more than 1000 people and sparked health alerts across multiple states, raising questions about whether it poses a risk to Canadian travellers as well.

While Canadian health officials say that there is currently no outbreak under investigation in Canada, the scale of the US surge has attracted international attention.

What is Cyclospora?

Cyclospora is a microscopic parasite which causes an intestinal disease known as cyclosporiasis. The infection is popularly known for triggering prolonged watery diarrhoea often described by the health authorities as involving ‘frequent and sometimes explosive bowel movements’.

Common symptoms include:

• Low-grade fever
• Loss of appetite
• Fatigue
• Vomiting and nausea
• Stomach cramps
• Watery diarrhoea

The symptoms can appear anywhere from a few days to two weeks after exposure and might last several weeks when left untreated.

Is Cyclospora a new outbreak?

No, Cyclospora is not a new outbreak but a recurring seasonal illness that typically peaks in spring and summer. However, health officials say that the current Cyclospora parasite outbreak is unusually large, making it one of the biggest in the US in years.

The parasite spreads through water or food contaminated with human faeces. Past outbreaks have often been linked with fresh produce like:

• Blueberries
• Raspberries
• Basil
• Cilantro
• Lettuce

In fact, washing produce may reduce the risk but does not always remove parasites completely.

Where the Cyclospora parasite outbreak is happening

The US outbreak has spread across various states, with some of the highest case numbers reported in:

• Louisiana
• Massachusetts
• Illinois
• Texas
• New York
• Ohio
• Michigan (nearly 1000 cases reported)

Massachusetts health officials have also confirmed seasonal cases linked to the outbreak, while New York reported hundreds of infections since May.

Risk for Canadian travellers

As per the Public Health Agency of Canada, there is currently no active Cyclospora outbreak investigation in Canada. Officials also note that the parasite is uncommonly found in the Canadian drinking water supplies.

However, experts say Canadians travelling internationally, particularly to regions experiencing a surge in parasite-related diarrhoea, must remain vigilant about food safety.

Safety tips for Canadian travellers

To reduce the risk of Cyclospora infection, travellers must:

• Avoid food from questionable sources
• Wash vegetables and fruits thoroughly
• Drink treated and safe water while travelling
• Seek medical help when persistent diarrhoea develops after travel
• Be cautious with imported fresh produce during outbreak phase

Although Canada has not reported a related outbreak, the growing Cyclospora parasite outbreak in the United States highlights how quickly foodborne infections can spread across regions. For travellers, basic food safety precautions and awareness remain the best defence against such recurring summer health threats.

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