Douglas County health officials say it appears that the illnesses that struck dozens of children at Fire Ridge Elementary School this week were linked to the Noro virus.

The virus causes gastrointestinal illness resulting in nausea, vomiting and diarrhea.

Nearly a third of the students at Fire Ridge were out of class over the course of the week.

Officials believe the children were exposed in the school lunchroom but the source is not clear. It might have come from a food service worker or one of the students.

School officials say that 62 children were out on Wednesday, 44 on Thursday and 21 on Friday but the numbers from later in the week could represent children who were out for more than one day. Those numbers, consequently, do not necessarily add up to the total number of children affected.