The Public Health Agency of Canada is warning people in Ontario and Quebec not to eat romaine lettuce as it works with U.S. health officials to determine the source of an outbreak of E. coli infections in the two provinces and in 11 states.
As of Tuesday, there have been 18 confirmed cases of the bacterial infection in Canada, the agency said in a notice posted on its website. Fifteen cases of the illnesses were in Quebec and three were in Ontario.
“Currently, there is no evidence to suggest that residents in other parts of Canada are affected by this outbreak,” the notice said.
The illnesses believed to be associated with the outbreak began in mid-October and the risk appears to be “ongoing,” the Public Health Agency of Canada said.
“Recent illnesses indicate that contaminated romaine lettuce may still be on the market, including in restaurants, grocery stores and any establishments that serve food,” it said.
The warning includes pre-made salad mixes containing romaine lettuce.
Although no deaths have been reported, six people were hospitalized, the agency said.
The strain of bacteria in this outbreak, called E. coli O157, is the same one that appeared in another outbreak linked to romaine lettuce in December 2017, which also affected people in Canada and the U.S.
That outbreak investigation was declared closed in February 2018 after almost two months during which no illnesses were reported and various romaine lettuce samples tested negative for E. coli. However, the cause of the romaine lettuce contamination was never determined.
The fact that the strain is the same, the agency said, “suggests there may be a reoccurring source of contamination. Investigators are using evidence collected in both outbreaks to help identify the possible cause of the contamination in these events.”
E. coli O157 is more likely than other strains to cause illness, but most people “recover completely on their own,” the agency said. Those most at risk for developing serious complications are pregnant women, people with weakened immune systems, young children and seniors.
Some people can be infected with E. coli, but still spread the infection to others, the agency said.
Despite the current outbreak, neither the Canadian government nor the Food and Drug Administration (FDA) are issuing a formal recall of romaine lettuce.
“At this time, the origin of the romaine lettuce has not been confirmed,” said Anna Maddison, a spokesperson for the Public Health Agency of Canada in an email to CBC News.
“We are working with public health and food safety partners in both Canada and the U.S. to investigate possible sources of the lettuce as well as possible sources of contamination, but more information is needed and the outbreak investigation is ongoing.
“If contaminated food products are identified, the Canadian Food Inspection Agency will take the necessary steps to protect the public, including recalling the product as required.”
FDA Commissioner Scott Gottlieb also said his agency didn’t have enough information to request suppliers issue a recall, but he said supermarkets and restaurants should withdraw romaine products until the contamination can be identified.
According to the FDA, 32 people have become ill in the U.S.
Symptoms of E. coli illness include nausea, vomiting, headache, fever, severe stomach cramps and watery or bloody diarrhea. People usually get better within five to 10 days and there is no “real treatment” apart from staying hydrated.
E. coli bacteria are naturally found in the intestines of farm animals. Contamination of vegetables and fruit can occur when they come in contact with animal feces. Most forms of the bacteria are harmless.