She said a letter has been sent to all parents at Churchill High School with information about the COVID-19 case.
At Ross Sheppard School in Edmonton, a letter posted online Tuesday noted that students in three Grade 10 classes need to be tested and must self-isolate at home for 14 days.
The province also announced Wednesday the launch of a website to help parents track cases of COVID-19 in schools.
That number is lower than the list compiled by the advocacy group Support Our Students Alberta, which lists more than 20 COVID-19 cases confirmed by schools.More news: Ellen DeGeneres claims to speak about bullying allegations when chat show yields
"If your child is required to isolate, you will have received a call from the school", said the letter from principal Rick Stanley.
None of the schools have declared outbreaks and all remain open.
Dr. Deena Hinshaw, the province's chief medical health officer, said officials have counted 11 cases at 11 schools but none of the infections were acquired at the schools.
Alberta has 1,692 active cases of the novel coronavirus - the highest since May 9.More news: Prince Harry and Meghan refund United Kingdom taxpayers for home renovation
She said she's concerned with the rise in case numbers across the province.
"In a school context, there is a risk for students and staff only when an infectious person has been present that they may have come in contact with".
Alberta schools are now open under what the government considers Scenario 1, or near-normal operations with some restrictions in place to help slow the spread of the virus including mandatory masks for students Grades 4 to 12 in shared spaces when physical distancing is not possible. The province said the student wore a mask on the bus and in the school the entire time.
"The premier claimed this isn't about money, and that if we needed additional resources to ensure the safe re-entry of schools that resources would be made available", said Hoffman.More news: Eminem's Home Invader Told Him He Was There To Kill Him