What is shiga toxin-producing E. coli and why are Calgary children getting so sick?

A ballooning E.coli outbreak connected to Calgary-area daycares is sending dozens of children to hospital, some with serious complications, and sparking concern among parents and doctors alike.

According to Alberta Health Services (AHS), 128 cases of an E. coli strain that can be particularly dangerous for young kids have been identified so far and 25 children are in hospital.

In addition, three patients have already been released and three more are being treated in other provinces.

What is most worrisome, doctors say, is that nine children have been diagnosed with a severe complication that can force kids into dialysis treatment.

"This is not the typical type of E. coli that causes maybe a day or two of watery diarrhea, or 'traveller's diarrhea,' that some people talk about," said Dr. Stephen Freedman, an ER physician at Alberta Children's Hospital and professor in the Cumming School of Medicine at the University of Calgary.

This particular strain is a type of E. coli 0157. It is known as shiga toxin-producing E. coli (STEC) because it secretes a toxin that can lead to serious organ damage, often targeting the kidneys.

"This is one of the most distressing illnesses that we see," Freedman said in an interview on The Calgary Eyeopener.

This strain is often carried by cattle and can contaminate food, including meat (through the slaughtering process) and fresh produce (through water tainted by infected animal feces).

Eleven child-care centres have been shut down by health officials as they search for the source of this outbreak. Public health investigators suspect the culprit is likely a common food served from a central kitchen.

What is so problematic about this outbreak, according to doctors, is that it has taken root among children under the age of five — one of the most vulnerable groups.

"What's scary about this one is that it seems to have a large number of kids involved," said Dr. Cora Constantinescu, an infectious diseases specialist at Alberta Children's Hospital.

Early in the infection, symptoms can include diarrhea (sometimes bloody), vomiting and fever.

But the toxin can eventually lead to a condition known as hemolytic uremic syndrome (HUS), where the toxin enters the blood stream and attacks the kidneys, potentially leading to kidney failure.

According to Constantinescu, while most children who are infected will recover, approximately 10 to 20 per cent will go on to develop HUS.