EDMONTON -- Austin O'Brien High School is under COVID-19 watch after it added four new cases Tuesday and Wednesday.

The high school reported its first two cases of the coronavirus last Friday and Sunday.

On Tuesday, the school added two cases that sent 56 people into self-isolation, and a day later, a fifth case that did not require anyone else to go home, and a sixth case that forced 19 people to quarantine.

Alberta Health Services places schools under its watch category after they have five or more confirmed cases.

Another two Edmonton schools, Vimy Ridge and Highlands Schools, are under the category, as well as one elementary school in Calgary.

Louis St. Laurent, which reported a case Monday, added another case on Tuesday that sent 35 people into self-isolation, Edmonton Catholic Schools said.

Cardinal Leger also reported one case Wednesday that forced 62 people to quarantine.

Edmonton Public Schools reported two new cases of the coronavirus on Wednesday.

A day earlier, an individual at Brander Gardens School tested positive for COVID-19, sending 16 Grade 3 students, six people who ride the yellow bus and two staff members home.

And on Wednesday, Aldergrove School was qualified as at outbreak after a second person tested positive for the disease — although the two cases are not connected. Eighteen students and three staff members will self-isolate.