George Washington University officials alerted the campus Wednesday that about 85 students were infected by norovirus this week.

After testing by the university’s Student Health Service and D.C. Department of Health, officials confirmed that norovirus was the cause of dozens of cases of gastrointestinal illness since Monday, university officials said in a prepared release. They said they could find no common link for the infections, as students were affected who live at the Foggy Bottom campus, the Mount Vernon campus and off campus.

The ill students also attended classes, studied and dined at many locations, the statement said. Students were advised to wash their hands frequently and disinfect surfaces they use, and the school said it would increase the cleaning of commonly used areas.

The virus is usually not considered serious, the statement said, and most people recover in one or two days. Symptoms include diarrhea, vomiting, nausea and stomach cramps. Other symptoms are a low-grade fever, chills and muscle aches.