More than 100 students and teachers at a California middle school were sickened in a Norovirus outbreak that began at the end of last week and seems to be tapering off now. Last Thursday, 80 students called in sick to Medea Creek Middle School in Oak Park. This was an unusually high number, according to the school. By Friday, 150 kids were home from school, many reporting gastrointestinal symptoms such as vomiting, nausea and diarrhea. On Monday the number of absences had dropped back to 90, according to the Ventura County Health Department, which is leading the investigation. Samples taken from those sickened showed that they had been infected with Norovirus, a pathogen that causes inflammation of the stomach, intestine or both. It is unclear whether all of the absent students were sick or whether some stayed home to avoid catching the illness, but the school says over 100 students and staff reported being ill. So far, the source of contamination has yet to be determined, but school staff is working to sanitize the building to prevent the spread of the virus, which is transmitted via the fecal-oral route. “At MCMS, we have had crews sanitize all desks, doors, and other surfaces that students are in contact with,” said the school in a press release. “This process will continue. We are providing hand sanitizer in all classrooms and common areas. The situation will be closely monitored by VC Environmental Health and we will be following their advice and directives. All other schools will also be receiving a thorough cleaning of all surfaces, etc. and hand sanitizer for the classroom.” The school also gave instructions to family members of children who have fallen ill. “If your child has these symptons, please do not send him or her back to school until 48 hours after the symptoms have stopped. The virus is highly contagious during this period. It is still present in the stool for up to two weeks.” It is also important that infected individuals not prepare food and wash their hands frequently in order to prevent the spread of infection, notes Ventura County Public Health.