Mumps is an acute viral infection characterized by a non-specific prodrome with myalgia, loss of appetite, fatigue, headache, and fever. These symptoms are followed by acute onset of unilateral or bilateral tender swelling of the parotid or other salivary glands. Usually 60-70 percent of those infected have this typical acute parotitis, others are associated with non-specific or primarily respiratory symptoms but 20 percent may be asymptomatic. Complications can include inflammation of the testicles, ovaries, or breasts, meningitis, spontaneous abortion, and deafness.

The incubation period is usually 14 to 18 days (range 14 to 25 days) from exposure to onset of symptoms. Patients are infectious from 3 days before until 9 days after symptoms begin. Transmission is via direct contact with respiratory secretions or saliva. Treatment is symptomatic and supportive with patients kept in isolation. Quarantine and exclusion from school or work is mandated by the Department of Public Health for those who are ill as well as non immune contacts. If a significant number of cases should be identified within the Harvard community, students who have not been immunized or otherwise have proven mumps immunity may be asked to leave the University.