A "national outbreak" of a potentially deadly strain of E. coli may be linked to fast food restaurants, health officials say.
Six cases of E. coli O157 have been confirmed in New Brunswick, while Nova Scotia has had five and Ontario four.
An additional five E. coli cases identified by Nova Scotia health officials are still awaiting confirmation from the national laboratory in Winnipeg to see if they are from the same strain.
The source of contamination is still under investigation, but Dr. Eilish Cleary, the chief medical officer of health in New Brunswick, believes they could be connected to fast food restaurants.
"In our investigation, one of the significant facts is that all of these individuals have eaten in fast food restaurants, but there are a number of different restaurants that they’ve eaten in, and they all have consumed a wide range of food, including meat products and produce," Cleary said on Wednesday.
Officials believe the source may no longer be a threat, because no new cases have been reported since the holidays, and the normal incubation period is 10 days, she said.
Although the sixth case in New Brunswick was only confirmed on Wednesday, it was not a new case, said Cleary. The Fredericton patient was diagnosed over the holidays, like the others, but the case was previously attributed to one of the other provinces because the individual travels back and forth, she said.
"So it’s really a numbers reconciling as opposed to a new individual in Canada," she said, declining to say which other province the case had been attributed to, citing patient privacy.
"So we’re hopeful that whatever it was that caused the exposure has come and gone from the food chain here."
Still, it should be easier to narrow the source down now with all three provinces comparing notes, said Cleary.
"The more you have to compare, in terms of numbers, the greater the likelihood that we will identify something."
'We’re hopeful that whatever it was that caused the exposure has come and gone from the food chain here.'—Dr. Eilish Cleary, N.B. chief medical officer of health
Dr. Frank Atherton, Nova Scotia's deputy chief medical officer of health, agrees.
"We still have a very large provincial role to play but we need to look at it in the context of what's happening in those other provinces," he said.
"We know that there's a common source for this infection across the three provinces. That's important because it means, really, this is now a national outbreak."
E. coli O157 is the same strain that killed seven people in Walkerton, Ont., in 2000.
This particular strain of E. coli secretes a powerful toxin that can destroy red blood cells, leading to severe illness, high blood pressure and kidney damage.
The Public Health Agency of Canada has issued an advisory about the latest outbreak in the three provinces.
"Products contaminated with E. coli O157 can pose a serious public health risk," the release states.
"Since early January 2013, the agency has been leading a committee to investigate these illnesses that includes public health and food safety experts from the Canadian Food Inspection Agency, Health Canada and provincial health authorities," it states.
"Based on the ongoing epidemiological and microbiological investigations conducted to date, it is likely that the people involved all got sick from the same source."
E. coli can be transmitted by eating undercooked meat, food contaminated during preparation, or from another person infected with E. coli.
Dr. Robert Strang, the chief public health officer in Nova Scotia, has said the likely source of the outbreak is produce.
One of the possibilities being investigated is lettuce that may have been chopped or processed, he said.
Of the New Brunswick cases, two were in the Saint John region, while four were in the Fredericton area. All six patients are recovering, including the one who had to be hospitalized and has since been released.
Of Nova Scotia's 10 cases, five were in the Capital District Health Authority, two in the Guysborough Antigonish Strait Health Authority, and one each in Pictou County, Cumberland and Colchester East Hants health authorities. Those patients have all recovered, or are recovering.
E. coli O157 led to the biggest beef recall in Canadian history last fall. The Canadian Food Inspection Agency recalled more than 1,500 beef products that were packed at XL Foods, a meat processing plant in Brooks, Alta.
It also put two Fredericton teenagers in hospital in July.
Another outbreak of E. coli O157 in Miramichi in April hospitalized at least 13 people.
Symptoms of E. coli O157 resemble gastro-intestinal illness, such as severe cramps, bloody diarrhea, abdominal pain and vomiting.
Precautions include thorough hand washing after using the bathroom or changing diapers, peeling all raw vegetables and fruits before eating, thoroughly cooking all meat and preventing contact between cooked foods and raw poultry or other meats.