Purdue University announced Wednesday the school is investigating five probable cases of the mumps virus on its West Lafayette campus.
The school joins three other schools playing host to mumps outbreaks so far this year.
State health department data says the largest mumps outbreaks have occurred at Indiana University and Butler University, who have reported 17 and 24 confirmed cases, respectively.
State health department data indicates at least 45 people on Indiana college campuses have contracted mumps since January 1st. Those cases account for 18 percent of mumps cases nation-wide in 2016.
Mumps is spread through coughing and sneezing and is more likely to manifest in areas where people are crowded together. The Centers for Disease Control and Prevention says symptoms usually occur two weeks after infection.
Two weeks ago, Purdue students—along with countless other schools' students--were on spring break, crowded into cramped hotel rooms, sharing drinks and clothes.
Mugdha Golwalkar, vaccine-preventable disease epidemiologist for the state health department, says that could contribute to outbreaks spreading between schools.
“We may be seeing people from different universities going to the same locations,” she says “So there’s definitely a possibility that could be a factor.”
Golwalkar says the main concern for health departments right now is controlling the spread.
“The worry with vaccine preventable diseases, including mumps, is when you start to see a large number of cases you start to see those more severe presentations,” she says.
Purdue students returned from spring break on March 21st .
Butler, Indiana University and IUPUI (where a smaller outbreak occurred) all require students to receive an MMR vaccine, which protects against mumps. However, experts say even after two shots, the vaccine is not 100 percent effective for every person.