Mumps is a disseminated virus infection, although the main clinical feature is salivary gland enlargement. Evidence of nonsalivary gland involvement is most commonly seen in adults. In men, orchitis (usually unilateral) is reported in about 20% of cases. Adult women occasionally develop oophoritis. Persons of any age may be affected by meningoencephalitis, the most serious complication of mumps. This is reported in 0.5%-10% of patients. Many persons with CSF changes are asymptomatic. Females are affected five times more frequently than males. Complications of mumps may appear before, during, or after parotitis, sometimes even without clinical parotitis. Diagnosis is made by culture or serologic tests. Saliva is probably best for culture; mouth swabs or CSF can be used. Serologic tests require acute and convalescent serum specimens.