As the nation grapples with a measles outbreak, the number of mumps cases at Indiana University has more than doubled since last week, school officials said, with similar outbreaks occurring at Temple University and Penn State University. As of Thursday morning, there are 17 mumps cases at the Bloomington campus, up from seven last week. More than half of the cases have been linked to a single fraternity, which is where the disease is believed to have originated back in February, a school official said. “We feel confident about where a lot of this is coming from which has helped us deal with it,” university spokesman Chuck Carney told HuffPost. “It’s not sweeping broadly around the campus.” The university’s students are required to have two MMR vaccines ― for measles, mumps and rubella ― by their second semester at the school. There is an exemption for religious reasons.

Michael Hickey via Getty Images There were 17 known mumps cases at Indiana University in Bloomington on Thursday, a school official said.

Of the 16 cases known on Wednesday, Carney said 14 of them had received two doses of the MMR vaccine. One of them had received just one dose, and the other had not had one because of a religious exemption. A health clinic was recently held at the fraternity where the outbreak is believed to have originated and 58 percent of its members received a third MMR vaccine during it, Carney said. “What that does is it provides them with a boost of immunity for about a month so it helps them stave off the illness if they are exposed,” he said. The university is working to inform students about the disease’s spread and things they can do to avoid infection, which Carney said is “simply practicing good hygiene.” That includes washing hands frequently, not sharing drinks and sneezing in the crook of one’s arm and not their hands. “The basic things that you would do to avoid any illness,” he said. Temple University in Philadelphia had been dealing with a similar outbreak. As of Thursday, there are 155 cases associated with the Temple University outbreak. Twelve of them are from surrounding counties, while the other 143 are in Philadelphia, the city’s Department of Public Health said in an email.

ASSOCIATED PRESS A line of mostly students wait to enter a vaccination clinic amid a mumps outbreak on the Temple University campus in Philadelphia on March 27.