Alberta Health Services says E. coli cases related to daycare outbreak stable

Alberta Health Services say while the number of E. coli cases related to an outbreak at numerous Calgary daycares remains stable, health officials are watching for further secondary spread.

The health authority says there have been two additional lab-confirmed cases of the bacterial infection that have now been linked to the outbreak, up to 350 from 348 on Tuesday.

Eight patients are still receiving care at Alberta Children's Hospital for hemolytic uremic syndrome, a complication affecting the blood and kidneys.

Two of those children are on dialysis, but the health authority says all patients are in stable condition and responding to treatment.

The outbreak affecting 11 Calgary daycares was declared more than two weeks ago.

All of those daycares have reopened, but the central kitchen that's believed to be the source of the outbreak has been closed indefinitely and five other daycares are either closed or partially closed due to secondary spread.

Calgary JCC Child Care had its closure order extended for its infant and toddler rooms after additional children showed symptoms. The cases are not yet confirmed positive for E. coli, but the facility is to remain closed until at least Monday.

Parents received a letter from Alberta Health Services, late on Tuesday, saying "several" other cases of shiga toxin-producing E.coli had been identified.

In a statement shared with CBC News,  AHS said two new symptomatic cases, linked to the initial outbreak, were discovered on Tuesday, in addition to two previously confirmed cases. 

They're currently going through testing and have not been confirmed, AHS said.

"I don't expect we're going to see a surge," said Dr. Stephen Freedman, a professor of pediatrics and emergency medicine at the University of Calgary.

According to Freedman, some secondary spread is bound to happen  in an outbreak of this magnitude.

"That is totally within what we would expect to see given the large number of children infected in the primary outbreak and the fact that we know that 10 per cent of the initial cohort of kids in general will transmit their infection to another child," he said.

"You need 10 infected individuals, on average, to transmit it to one person. So I think given our numbers, given where we're at  and the messaging…in terms of the prevention of transmission, we really should not see significant further secondary spread."

AHS is reminding Albertans that anyone with E. coli symptoms, including diarrhea, nausea, stomach cramps, vomiting and fever, should stay home from daycare, school or work, in particular work that involves food handling or caring for children, patients or seniors.

"It is crucial for parents who have children who attend these daycares to follow the guidance being given to them by healthcare professionals," spokesperson Kerry Williamson said in a statement.

"If you have received an exclusion order, please keep your children at home. Only send your child to a childcare facility once you have been issued a clearance letter from AHS."

As of Wednesday, the  number of lab-confirmed secondary cases currently was unchanged at 27.

The number of lab-confirmed secondary cases currently remains at 27.

A total of 825 children connected to the outbreak have been cleared to return to daycare.