Minnehaha Academy in Minneapolis closed its Upper School campus for the rest of the week after what appears to be an outbreak of the norovirus.

The Lower and Middle schools, which are located in a building 1 1/2 miles south of the Upper School campus, are not affected by the closure.

School officials notified the Minnesota Department of Health, which indicated the widespread illness appears to be the norovirus. Students who contract the virus are advised to stay home for at least 24 hours after all the symptoms end.

Norovirus can cause the sudden onset of severe vomiting and diarrhea, according to the Mayo Clinic. The virus is highly contagious and commonly spread through food or water that is contaminated during preparation or contaminated surfaces. You can also be infected through close contact with an infected person.

Diarrhea, abdominal pain and vomiting typically begin 12 to 48 hours after exposure, according to the Mayo website. Norovirus symptoms last one to three days.

Since October, more than 60 norovirus outbreaks affecting about 1,000 people have been reported to state health officials, according to Health Department spokesman Doug Schultz. Ten gastrointestinal virus outbreaks were school related, he said. Most others occurred in long-term care facilities.

The number of outbreaks this season appears to be above average but not extraordinary when compared to historical statistics, Schultz said.

On Wednesday about 90 Minnehaha Academy students and staff members called in sick or got sick at school with similar symptoms, school president Donna Harris said. The numbers quickly climbed in the morning, reaching the threshold when the Minnesota Department needed to be notified, she said. The Upper School at 3100 West River Parkway has 340 students in the ninth through 12 grades.

There doesn't appear to be a common source, such as the cafeteria, for the outbreak, Harris said. School officials will monitor absences in the Lower and Middle schools because older siblings could spread the virus to them, she said.

The Upper School was closed at noon Wednesday to help stem the spread of the virus. An industrial cleaning service will clean and sanitize the building, according to a message posted on the school's website.

The Upper School will reopen Monday.

Students should check the school's digital learning program and e-mails for the rest of the week.

Mary Lynn Smith • 612-673-4788