Health officials are continuing to search for the culprit behind a cluster of daycare-associated Escherichia coli infections affecting children in Canada.
An outbreak of Shiga-producing E. coli was officially declared in Calgary, Alberta just over a week ago, after doctors there saw an influx of children with symptoms such as bloody diarrhea visiting the city’s emergency rooms over the Labor Day long weekend.
“On September the 4th, [the provincial health agency] Alberta Health Services declared an E. coli outbreak in the Calgary zone,” Alberta’s Chief Medical Officer of Health Mark Joffe explained during a video news briefing today. “This was prompted by a noticeable increase in young children coming to the emergency departments in the city with gastrointestinal complaints, including bloody diarrhea.”
As doctors began to link cases to daycare centers in the city, suspicion soon fell on a centralized kitchen shared by 11 childcare sites. Investigators have not yet found a concrete source of infection, though the kitchen is closed during the search.
“This is an ongoing, very complex investigation that does take time,” Joffe said, calling the outbreak “extraordinary” in terms of its severity and the number of people affected.
To date, there have been 264 lab-confirmed cases of Shiga toxin-producing E. coli infections, most in children under five years old — a group that is especially vulnerable to severe health complications such as hemolytic uremic syndrome (HUS), which affects the blood, small blood vessels, kidneys, and other organs.
More than two-dozen children and one adult are currently hospitalized, and 22 cases have progressed to HUS. Six children are receiving dialysis due to related kidney problems. Still other individuals were already treated and released from hospital.
“While our frontline workers are caring for these symptomatic and sick children, our public health experts are investigating to determine what happened and how to stop an outbreak of this magnitude from ever, ever happening again,” Adriana LaGrange, the province’s health minister, told reporters.
In particular, Joffe said provincial public health investigators have turned to whole-genome sequencing to profile E. coli isolates from infected individuals to see if they are genetically similar to those found in other parts of the country or internationally in the past.
Such genetic investigations are “routine” in this type of outbreak, he emphasized, adding that “we have no indication that the outbreak occurring in Calgary is linked in any way to any other site.”
He noted that public health inspectors have collected samples of 11 food types found in a centralized kitchen suspected in the outbreak, along with eight samples of leftover food from childcare sites. So far, all the food samples have been negative for Shiga toxin-producing E coli.
The team is also considering epidemiological evidence — from the timing of when children at different locations began experiencing symptoms to investigations into the foods delivered to sites with distinct infection rates.
“Based on the epidemiology of the cases we’ve seen to date, it seems highly likely that the source of the outbreak is food that was distributed from [a] central kitchen,” Joffe said. “This kitchen remains closed and will only reopen once we are absolutely satisfied that it is safe.”
Shiga toxin-producing E coli outbreaks are most often associated with food products, particularly undercooked meats and food such as raw milk that have come in contact with material from cattle in some way. But it can also spread via contaminated water, fecal matter from infected animals (including humans), or produced exposed to such water or… material.
Canada’s largest known E. coli outbreak took place more than 20 years ago, when drinking water in Walkerton, Ontario became contaminated with manure, CBC News reports, Thousands of people became infected and seven people died during that outbreak in 2000.
An environmental health inspection report released by Alberta Health Services today revealed three “critical” violations found at the daycare-associated food facility during an inspection done after the latest outbreak was announced last week.
Those violates were related to food handling, equipment sanitation, and pest control. Investigators also found two non-critical violations, including a sewer gas smell near a food preparation area. The same facility was investigated five times previously this year.
As CBC News reported today, last week’s inspection found living and dead cockroaches on site, among other problems.
For her part, Tania Principi, section chief of pediatric emergency medicine at Alberta Children’s Hospital, outlined the care being provided to young pediatric patients currently hospitalized with E. coli infections. Most are getting intravenous fluids, she noted, though some children have received blood transfusions and a small subset require dialysis.
Far more children across the western Canadian city have been tested for E. coli after attending one of the daycares, and public health officials have been continuing to track cases and potential secondary infections within their homes.
In an opinion piece in the Globe and Mail, health reporter and columnist André Picard pointed to public health issues behind the outbreak. Last week, the Calgary Herald reported that affected families have filed a class-action lawsuit related to the outbreak.
Several childcare sites associated with the outbreak are currently closed. Four sites that shared the same kitchen have reopened this week. Global News reported that no lab-confirmed cases were detected at the newly reopened locations.
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