Alberta Health Services (AHS) says as of Wednesday morning, the number of confirmed cases of E. coli connected to 11 Calgary daycares and a common kitchen between them is 310.
Twenty-one of those cases -- all children -- are receiving care.
Hemolytic uremic syndrome (HUS) developed in 20 patients, seven of whom are on dialysis.
Fourteen patients have been released from hospital since the beginning of the outbreak.
Eighteen secondary transmissions have occurred, all within households linked to the outbreak, which AHS says shows the outbreak has remained well-contained.
Symptoms of diseases caused by E. coli include intestinal pain and diarrhea, which in some cases may be accompanied by bleeding or turn into hemorrhagic colitis. Fever and vomiting are also possible. The incubation period lasts from three to eight days, with an average duration of three to four days. Most patients recover within 10 days.