NORTH PHILADELPHIA (WPVI) -- We are now three weeks into the mumps outbreak, and more students are becoming sick.
One of the reasons we're seeing it continue is because of the long incubation period of the mumps.
Right now, 74 out of 40,000 students have been infected at Temple's two campuses. An online petition was posted Wednesday calling on the school to close, but experts say that wouldn't make a difference.
It seems to happen about every 5 years - a rise in mumps outbreaks on college campuses.
Dr. Kirsten Feemster, a communicable disease expert with the Philadelphia Health Department, says it may be due to several factors coming together.
First, the virus spreads easier in close quarters.
"Contact with someone who is talking, sneezing, or coughing," said Dr. Feemster. "Parties, lectures where you're sitting close to your classmates. You may be sharing a room."
Unlike the measles outbreaks reported around the country in recent years, most who develop mumps are vaccinated with 2 doses of the measles-mumps-rubella vaccine, or MMR. But, some people lose a little immunity - right about the time they're in college.
Still even if they do get the virus, being previously vaccinated helps.
"You're less likely to have severe symptoms and to develop complications," said Dr. Feemster.
Experts say closing Temple wouldn't stop the virus. It can take weeks for symptoms to develop and people who were exposed before the closing can get sick and still spread the virus after the school re-opens.
Dr. Feemster says there are more important measures -
"Making sure that you cover your cough, you're washing your hands, you're not sharing cups or utensils with friends," she said.
Mumps cases at Temple University continue to climb