Rising Cases of Cyclosporiasis in Canada and the United States
As of July 13, the Centers for Disease Control and Prevention reported 1,645 laboratory‑confirmed cases of cyclosporiasis across 34 U.S. states, with 141 people hospitalized after eating contaminated food. A week earlier, on July 9, the count stood at 843 cases in 31 states and 86 hospitalizations, showing a rapid upward trend. The CDC notes that state health departments are likely reporting higher numbers than those reflected in the national data.
In Canada, the Manitoba and Ontario health departments have each recorded multiple cases, while the Northwest Territories, Nova Scotia, New Brunswick and Prince Edward Island have reported none this year. Alberta announced five cases by July 13, none linked to recent travel to the United States, and Nunavut confirmed five infections without any evidence of a food‑borne outbreak or connection to U.S. imports.
Case Numbers by Province and State
The Michigan Department of Health and Human Services listed a total of 3,762 cases, and Ohio reported 177 cases as of July 2. These figures illustrate the breadth of the outbreak beyond the United States border.
How Cyclosporiasis Spreads
The parasite that causes cyclosporiasis must survive outside a human host for several days before it can be ingested, which makes person‑to‑person transmission rare. Dr. Isaac Bogoch, an infectious disease specialist, explains that most infections stem from eating contaminated foods rather than from contact with an infected person.
Symptoms can include watery diarrhea, abdominal bloating, loss of appetite and other gastrointestinal discomforts. The incubation period averages about seven days after accidental ingestion of the parasite.
Foods Most Likely to Carry the Parasite
Public health officials have identified several fresh produce items that frequently harbor Cyclospora. Leafy greens such as lettuce, herbs like coriander and basil, spring onions, raspberries and sugar snap peas are highlighted as higher‑risk foods because their surfaces can trap the parasite.
To reduce risk, experts recommend purchasing whole heads of lettuce and discarding the outer leaves, washing all produce thoroughly under running water, and cooking items when possible. Heating food to at least 70 °C reliably kills the parasite, and washing even peelable fruits under clean water helps remove contaminants.
Public Health Responses and Prevention Guidance
The Public Health Agency of Canada states that cyclosporiasis is a nationally notifiable disease, though case numbers are compiled annually. Investigations are launched when outbreaks involve more than one province or cross borders. PHAC is collaborating with provincial health authorities, the Canadian Food Inspection Agency and Health Canada to trace any source of infection.
While the agency notes that washing produce does not always eliminate the parasite, it advises Canadians to follow safe food‑handling practices, choose fresh domestically grown produce during the spring and summer months, and cook imported items thoroughly. Heating to high temperatures and thorough washing are the most effective preventive measures.
Canada imported roughly $5.5 billion worth of fresh produce from the United States in 2024, with lettuce and strawberries being the most common items. Despite the significant volume of imports, health officials stress that there is currently no evidence of a widespread Canadian outbreak linked to U.S. foods, and they do not recommend halting consumption of American products.
