The number of University of Minnesota students diagnosed with mumps is up to 25­­­­­, after the University reported seven students with the infection April 23.

All cases so far have been mild and only among vaccinated students, said Medical School Dean Brooks Jackson in an email to University students, faculty and staff Friday.

Gary Christenson, Chief Medical Officer at Boynton Health, said the sudden uptick in cases is likely due to the 16- to 18-day duration of the illness when students can infect each other up to two days before and four days after symptoms stop showing.

The illness may appear to leave only to be followed weeks later by a large second round of cases, he said.

He added students should avoid sharing cups and eating utensils and make sure to wash down surfaces that have been exposed to the illness to avoid further infection.

“We’re directing students to quarantine themselves and telling them to request time off from exams,” Christenson said. “This is obviously a terrible time to get ill.”

He said although the timing is poor for students taking exams, it may help prevent further spread of the illness since many students are spread out and not concentrated in the same location.

Christenson said the University is staying in contact with the Minnesota Department of Health to discuss possible plans of action in case the illness doesn’t fade before students return in the fall.