Mumps is a contagious disease caused by a virus. It typically starts with a few days of fever, headache, muscle aches, tiredness, and loss of appetite, followed by swollen salivary glands.You can protect yourself and your family against mumps with vaccination.umps is no longer very common in the United States, but outbreaks continue to occur. Outbreaks have most commonly occurred in places where people have had prolonged, close contact with a person who has mumps, such as attending the same class, playing on the same sports team, or living in the same dormitory.