Here are some of the biggest E. coli O157 outbreaks in Canada

E. coli has infected more than 260 people in Calgary outbreak — but it's far from the biggest in Canada

Image | Walkerton 10 Year Memorial 20100516 TOPIX

Caption: During a memorial ceremony in Walkerton, Ont., on May 16, 2010, people gather around the defunct well where the original water contamination began. The E. coli outbreak killed seven people and made almost 2,500 others sick. (Nathan Denette/The Canadian Press)

An outbreak of E. coli infections at several Calgary daycares has infected more than 260 people, most of them children. It's not the first major outbreak of the food-borne illness, which is caused by bacteria that live in the feces of animals and is carried to humans through undercooked meat, unpasteurized food or contaminated water.
The E. coli variant known as 0157 is often the most virulent and can cause hemolytic uremic syndrome, which affects the kidneys and the ability of blood to clot.

Here's a chronological list of some of Canada's other major E. coli O157 outbreaks.
1980: In one of the first recognized outbreaks of the E. coli, 14 Toronto-area children fell sick with hemolytic uremic syndrome and one of them eventually died. Doctors traced the outbreak to unpasteurized apple juice.
1982: An outbreak in an Ottawa nursing home affected 31 residents. One person died. Undercooked hamburger was the suspected source.
1985: Seventy-three residents and staff in a nursing home in London, Ont., fell sick after eating uncooked meat in sandwiches. Nineteen residents died.
1991: In what was then the Northwest Territories, 521 Inuit in six communities were sickened over several months. Contaminated beef and caribou were considered the likely sources of outbreaks that caused 22 cases of hemolytic uremic syndrome. Two people died.
1999: Dry salami was linked to an outbreak in British Columbia that infected 143 people.
2000: Canada's largest outbreak occurred in Walkerton, Ont., when manure-tainted drinking water caused more than 2,300 cases. Seven people died.

Image | Beef Recall Lawsuit 20141126

Caption: Two people wearing fluorescent safety vests stand atop a pile of packaged beef products from the XL Foods cattle processing plant as more are dumped at a landfill site near Brooks, Alta., on Oct. 22, 2012, after an E. coli outbreak prompted the largest meat recall in Canadian history. (Jeff McIntosh/The Canadian Press)

2012: XL Foods recalled more than 1.8 million kilograms of beef in Canada and the United States from a processing plant then operated by XL Foods Inc., in Brooks, Alta., after health officials confirmed that 18 Canadians tested positive for E. coli bacteria linked to meat from the plant.
2014: Contaminated pork sickened 119 Albertans.
2018: Eighteen people in Quebec and Ontario were infected and six were hospitalized after eating contaminated lettuce.
2019: Packaged salad kits were identified as the most likely source of contamination that infected 28 people across seven provinces. Eight were hospitalized.
2022: Contaminated kimchi sickened 14 people in Alberta and Saskatchewan. None were hospitalized.
2023: An outbreak of E. coli is declared on Sept. 4. As of Sept. 12, the exact cause of the outbreak was still under investigation but Alberta Health Services said it was believed to have originated in a food source from a central kitchen used by multiple daycares. By Sept. 12, AHS said the outbreak had grown to include 264 lab-confirmed cases, mostly among children. Twenty-five patients receiving care in hospital, 22 of whom were confirmed as having hemolytic uremic syndrome. Six patients were receiving peritoneal dialysis.
WATCH | Alberta officials investigating Calgary E. coli outbreak:

Media Video | CBC News : Hear the full news conference as Alberta health minister, chief medical officer speak a week after the start of an E. coli outbreak that has affected more than 260 people, mostly children

Caption: Minister of Health Adriana LaGrange and Minister of Children and Family Services Searle Turton join Dr. Mark Joffe, chief medical officer of health, and Dr. Tania Principi, section chief of pediatric emergency medicine at Alberta Children’s Hospital, to discuss the measures being taken to address the current E. coli outbreak at daycares in Calgary.

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