Mumps Mumps is a disease caused by a virus and occurs only in human beings. Mumps is found all over the world. Mumps is a contagious disease when the salivary glands, on one or both sides of the jaw, swells. Mumps usually occurs in school age children, but young adults may catch the disease. Everyone born before1957 has already had mumps. After one attack of mumps, you will have lifelong immunity. The mumps virus is spread by contact of another person's discharge from the nose or mouth. The virus is present in these discharges from six days before symptoms to nine days after the glands begin to swell. The virus will then incubate for two to three weeks bef