Citing “increased absences,” two middle schools in Mesa County Valley School District 51 closed today after noon after the spread of what is “most likely norovirus.”

CPR reports that Rocky Mountain Elementary School, Palisade High School and Mount Garfield Middle Schools have all closed temporarily for cleaning. 

On Nov. 14, 30% of Palisade students called in sick. Mount Garfield closed on Nov. 18 and reopened on Wednesday, but absences prompted the early dismissal.

“When schools are at or approaching 10% absenteeism due to illness, schools receive additional disinfecting above the regular amount of cleaning performed each day at schools,” the school district wrote on its website. 

Custodians are using bleach to disinfect the premises. The primary symptoms reported in students are vomiting and diarrhea. 

The school district recommends that students or staff should stay at home until at least 24 hours after the final instances of vomiting.

The Centers for Disease Control and Prevention describes norovirus, also known as stomach flu, as a highly contagious virus that transmits from contact with an infected person, consuming contaminated food and water, and putting hands to one’s mouth after touching an infected surface. Most people so afflicted recover within one to three days.