Health officials say 23 cases of mumps are confirmed in an outbreak at Ohio State University. Eighteen students and a staff member are among those infected.

University and public warned Ohio State students, faculty and staff to take precautions to keep themselves healthy as they headed back to class Monday after .

A Columbus Public Health spokesman says authorities are mapping cases to determine how people became infected and any links between them. He says three people have been hospitalized for at least one day.

The confirmed cases involve 11 women and 12 men. They range in age from 18 to 48.

The spokesman says they include a relative of a student and three people who don't study or work at Ohio State but have links to the university community.