Schools will remain closed on Friday and through the district's Thanksgiving break, which lasts the entire week of the holiday from Nov. 25-29.

Mesa County health officials think norovirus is a possible cause of the outbreaks. The main symptom is vomiting that lasts between 12 and 24 hours, with a few reports of diarrhea, as well.

Officials warned the public that when it comes to norovirus, not all cleaning liquids and hand sanitizers can kill the germs. People sick with the virus can continue to spread the illness 24 hours after symptoms have passed. Officials urged parents to keep their children at home if they show any signs of illness.