On Thursday, nearly 150 students at Trillium Public School in Kitchener came down with a gastrointestinal illness.

The students – nearly half the school’s population – were either sent home or didn’t come to school that day.

“My son was in the office feeling ill and he had thrown up,” says Susan Marostega. “I went to pick him up, and brought him home. It was pretty clear right off that it was some type of a stomach virus.”

The Waterloo Regional District School Board suspects it was a Norovirus outbreak, but it has not yet been confirmed by Public Health.

“It wasn’t a long drawn out process,” says mom Susie Deyo. “But it was pretty dramatic when it did happen.”

Classes were cancelled on Thursday, and students were sent home. Friday was a P.D. Day for students, and all scheduled parent-teacher meetings were cancelled as well.

The school’s biggest concern is stopping the spread of this highly contagious virus.

“We know when you’re sick, Norovirus is landing on everything,” says epidemiologist Kimberly Repp. “[You don't] just wipe down the toilet when someone’s sick. We need to think about everything, sitting on the counter… anything that can be touched by someone else, clean that too.”

That’s something Kelly Mann understands all too well. She has three sick kids who are students at two different schools. “I had to do loads and loads of laundry just to kill all the germs,” she says. “I scrubbed walls, scrubbed floors.”

TrilliumPublic School has also had a thorough cleaning, and officials say it will re-open on Monday.