The number of students sickened by a mystery illness at Ursinus College in eastern Pennsylvania has risen to over 170.

College spokeswoman Esme Artz says 174 have shown signs of a stomach infection. Overnight, two students went to the , and two others were taken to a hospital Thursday morning.

The school closed its cafeterias and snack bar after students began complaining of vomiting, diarrhea and Tuesday night.

Classes remain open, but weekend events have been canceled.

The school is working with Montgomery County health authorities to try to determine whether the ailment is foodborne or transmitted from person to person.

Ursinus has partnered with Wawa, Wegman's, local pizza shops and a bakery to provide food while the cafeterias are closed.