|Description||Symptoms begin with a headache and fever for a day or two before the disease is characterised by swelling of the parotid glands which may be unilateral (one side) or bilateral (both sides). However, at least 30% of cases in children have no symptoms. Complications of symptomatic mumps include swelling of the ovaries (oophoritis), swelling of the testes (orchitis), aseptic meningitis and deafness. Cases may have no salivary gland involvement but develop symptoms elsewhere (orchitis, meningitis). Despite common belief there is no firm evidence that orchitis causes sterility. Other symptoms may include pancreatitis, neuritis, arthritis, mastitis, nephritis, thyroiditis and pericarditis. Mumps was the commonest cause of viral meningitis in children prior to 1988, when vaccine was introduced.
The incubation period is 14-21 days and mumps is transmissible from several days before the parotid swelling to several days after it appears. Contagiousness is similar to that of influenza and rubella but not as infectious as chickenpox or measles. Exposed individuals should be considered infectious from 12 to 25 days after exposure