Canada warns travellers of cyclosporiasis outbreak in U.S. with 4,173 confirmed cases
Global Affairs Canada issued an advisory about an intestinal parasite causing severe diarrhea, with cases confirmed across multiple U.S. states since May.
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The Canadian government is warning travellers about cyclosporiasis, a serious intestinal illness caused by the parasite cyclospora, spreading across multiple U.S. states.
Since May 1, the U.S. Centers for Disease Control and Prevention has confirmed 4,173 domestic cases of cyclosporiasis. As of July 21, the CDC is aware of over 7,400 additional unconfirmed cases. People contract the parasite by eating or drinking water that contains it, though it is unlikely to spread directly between people.
Most people infected with the parasite experience watery diarrhea. Without treatment, symptoms may persist for days to months — typically six to seven weeks — and may disappear and then return.
Canada's government recommends several steps to reduce infection risk while travelling to affected states: thoroughly wash fresh fruits and vegetables under clean, cool running water before eating; disinfectants and produce washes may not completely remove cyclospora; wash produce even if labelled as pre-washed or ready to eat; cook produce while travelling in states experiencing outbreaks; and follow safe food and water practices throughout your trip. If you develop diarrhea that is severe, watery, or lasts more than a few days, seek medical attention.
By the numbers
How many cyclosporiasis cases has the CDC confirmed in the U.S. since May 1?
Since May 1, 2026, the U.S. Centers for Disease Control and Prevention has confirmed 4,173 domestic cases of cyclosporiasis.
How long do cyclosporiasis symptoms typically last without treatment?
Most people infected experience watery diarrhea that typically persists for six to seven weeks without treatment, though symptoms may disappear and then return.
How do people contract cyclosporiasis?
People contract cyclosporiasis by eating or drinking water that contains the cyclospora parasite, though it is unlikely to spread directly between people.
