Leo Nickerson School in St. Albert. (Google Street View)

Alberta Health Services has sent a letter out to parents at Leo Nickerson School in St. Albert after someone at the Sigis Daycare attached to the school tested positive for COVID-19.

The letter, dated Sunday, doesn’t specify whether the case was in a student or staff member.

St. Albert Public School told CTV News Edmonton that approximately 18 students and five staff members are affected.

Affected students and staff must quarantine for 10 days, or until they get a negative test result for COVID-19.

The school is scheduled to undergo extensive cleaning on Monday.

Two cases of COVID-19 were also confirmed at Edmonton schools last week.

One was detected Wednesday at Ecole Saint-Jeanne D’Arc Elementary. Officials said the case is considered low risk.

The second was detected Friday at Louis St. Laurent Junior/Senior High School. The Catholic school board said it was a student who has not been at school since last Wednesday, and is now self-isolating.