In the past month, 128 cases of mumps were reported at the University of Missouri on the Columbia campus -- one of a handful of U.S. colleges facing outbreaks during the worst year for mumps in the past decade.

As of Nov. 5, 2,879 people were infected by mumps in 45 states, according to the Centers for Disease Control and Prevention. That’s more than double the reported mumps infections in 2015.

Mizzou has seen the greatest number of mumps cases since the outbreaks began, and as a result, the university has asked student groups to cancel nonmandatory social events as the semester winds down. The State University of New York at New Paltz has also seen many cases of mumps, with 32 infections confirmed after the first outbreak in October. Students at Yale University received an email in late November about two suspected cases of mumps on campus.

Mumps infections have also been spreading in the Boston area. Nine cases were confirmed on the Medford campus of Tufts University. At least four infections were diagnosed at Harvard University, months after an outbreak of 66 mumps cases in the spring. Also earlier this year, 65 people were diagnosed with mumps in Indiana, most of them at universities.

Mumps is a highly contagious respiratory virus. It causes swollen salivary glands, fever and muscle aches, and symptoms generally last for two to three weeks. It is easily spread through coughing, sneezing, talking or sharing objects, according to the CDC.