Caused by a virus, mumps is a salivary gland infection. It takes between 12 and 25 days for symptoms of this disease to show after infection. People may be infectious 6 days before symptoms develop and up to 9 days after they go away. The mumps virus is passed through air droplets and contact with the saliva of an infected person.

Mumps was a common and typically very mild childhood disease prior to widespread vaccine use. Permanent long-term complications are rare and about 35% of infections are actually asymptomatic and go virtually unnoticed. It becomes more potentially serious in adolescence and adulthood (although the greatest advertised fear, that of sterility in adult males, is relatively rare).