Mumps is transmitted by direct contact with saliva and discharges from the nose and throat of infected individuals. Approximately one-third of infected people do not exhibit symptoms. The incubation period is usually 16 to 18 days, although it may vary from 14 to 25 days. Swelling of the testicles occurs in 15-25 percent of infected males. Other complications include arthritis, kidney involvement, inflammation of the thyroid gland and breasts and deafness.
Mumps is contagious seven days prior to and nine days after the onset of symptoms.
A person is most contagious 48 hours prior to the appearance of symptoms. Immunity acquired after contracting the disease is usually permanent. Mumps vaccine is given on or after a child's first birthday, but is recommended at 15 months of age if administered in combination with measles and rubella vaccine. The vaccine is highly effective and one injection usually produces lifelong protection. The single most effective control measure is maintaining the highest possible level of immunization in the community.