Amid the rapid U.S. spread of cyclosporiasis, an illness of the intestines caused by a parasite called cyclospora, questions surrounding potential prevention of the sickness continue to circulate.
That comes as the Canadian Food Inspection Agency says it is not considering restrictions on fresh produce imports from the United States, and after the Public Health Agency of Canada says it is not investigating any outbreaks.
As of July 13, 1,645 lab-confirmed cases were reported in the U.S. across 34 states, with 141 people hospitalized, according to the Centers for Disease Control and Prevention (CDC), with those becoming sick “after eating food in the United States.”
On July 9, 843 cases were reported across 31 states, resulting in 86 hospitalizations, marking a quick rise in cases. The CDC does indicate that “states are likely to report higher case counts of cyclosporiasis than reflected in CDC data.”
The Michigan Department of Health and Human Services (MDHHS) has reported 3,762 total cases, while Ohio’s Department of Health has recorded 177 cyclosporiasis cases in the state as of July 2.
The source of the rising cases has yet to be pinpointed, with the CDC saying that “investigations to identify source(s) of illness are ongoing.”
Those sick also “did not report any travel during the 14 days before they got sick,” according to the CDC.
While the (PHAC) told Global News that no Canadian cyclosporiasis outbreaks are currently being investigated, the agency did note that “there is usually an increase in cyclospora infections acquired in Canada linked to consuming fresh fruit and vegetables imported from other countries during the spring and summer.”
The PHAC also told Global News that cyclosporiasis is “a nationally notifiable disease in all provinces and territories,” yet information surrounding case counts “is shared on an annual basis.”
Investigations, the agency noted, happen in outbreaks involving more than one province/territory or that involves Canada and another country.
The agency also works alongside provincial and territorial health authorities, the Canadian Food Inspection Agency, and Health Canada to investigate any source.
Global News reached out to provincial health officials directly asking whether their departments had seen any cases of the parasite and whether any are linked to U.S. produce.
Global News confirmed that the Northwest Territories, Nova Scotia, New Brunswick and Prince Edward Island say they have seen no cyclosporiasis cases this year.
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Alberta health officials told Global News that the province has seen five cases of cyclosporiasis as of July 13, with none of the cases involving recent travel to the U.S. Follow up questions about whether any of the individuals had consumed any produce imported from the U.S. went unanswered.
Nunavut health officials confirmed five cases lab-confirmed cases this year, stating to Global News “there is no evidence to suggest that the case identified in Nunavut is linked to any ongoing foodborne outbreak or to imported fruits or vegetables from the United States.”
Two cases were reported to Public Health Ontario in March, officials there said. Manitoba health officials have also reported one case this year that is currently under investigation.
Quebec media have also reported, citing provincial health ministry statements, that cases are rising in the province this year but do not have any clear link to the U.S. outbreak.
Global News has asked the Quebec health ministry for that statement, but has not received a response.
The risk of contracting cyclospora is also “not common on food and is not in drinking water in Canada.”
The illness also has “remarkably little” human-to-human transmission.
“The parasite has to go through its life cycle, and it requires several days outside of a human host before it can be ingested and infectious to another human,” Dr. Isaac Bogoch, an infectious diseases specialist at the Toronto General Hospital said.
“So, these cases are very likely to be primarily from ingestion of a contaminated food, like a fruit or a vegetable, and not significantly from human-to-human transmission.”
The symptoms of cyclosporiasis can vary between watery diarrhea, abdominal bloating and gas alongside loss of appetite, among others.
Between 2004 and 2019, an average of 238 Canadian cases of cyclosporiasis were reported annually through the Notifiable Disease Surveillance System.
For those who are worried about potentially ingesting the parasite, PHAC says there are some steps that can reduce risk of exposure.
- Follow safe food handling practices for produce on a daily basis.
- Cook produce imported from countries where cyclospora is found.
- Consume fresh produce grown in Canada, especially during the spring and summer months when an increase in cyclospora infections linked to consuming fresh fruit and vegetables imported from other countries are reported.
The Michigan health department says there are several specific foods people should be careful with:
- Lettuce/leafy greens: Buy whole heads of lettuce (rather than prewashed, bagged lettuce or salad mixes), throw away the outer two–three layers of leaves and wash the inner leaves under running water. For leafy greens that can be cooked, cooking is the safest option.
- Cilantro, basil: Wash thoroughly under running water, separating the leaves. Safest when cooked.
- Green onions: Trim the root end and remove the outer layer, wash thoroughly under running water. Safest when cooked.
- Raspberries: Their bumpy surface makes them especially hard to clean; the parasite can hide in the tiny crevices. Safest when cooked (pies, jams etc.) Consider frozen raspberries as an alternative (freezing may reduce but does not guarantee elimination of the parasite).
- Snow peas: Wash under running water and rub the surface. Safest when cooked.
Heating food to 70 C or higher can also kill the parasite, along with washing all fresh produce under clean running water, even if the food can be peeled.
Many times, the ingestion of contaminated foods is “accidental,” according to Bogoch.
“You think about where a food can get contaminated and you have to think about all the steps, from when a crop is grown to how it’s harvested, to how its transported, to how it is processed, how it ends up on a grocery store shelf,” he said. “But much of the time, some of the contamination can her while the crop is still on the farm.
“After the accidental ingestion of this, it has an incubation period of about seven days.”
Unless Canadians start to contract the illness, Bogoch does not believe they should stop purchasing or consuming American produce.
“We don’t have any reports of outbreaks of this is Canada, so for us it’s business as usual.”
The PHAC states that cyclosporiasis “can be hard to prevent,” because “washing produce does not always get rid of the cyclospora parasite that causes the illness.”
According to the Canadian Produce Marketing Association, Canada imported $5.5 billion in fresh produce from the U.S. in 2024, representing nearly half of all fresh produce imports.
Lettuce is listed as the top U.S. commodity imported to Canada, with strawberries coming in second.