Mumps is an acute viral illness. although the parotitis and orchitis were described by Hippocrates in the 5th century B.C., until relatively recently mumps was viewed primarily as an illness that affected armies during times of mobilization. In 1934, Johnson and Goodpasture showed that mumps could be transmitted from infected patients to rhesus monkeys and demonstrated that mumps was caused by a filtrable agent present in saliva. This agent was later shown to be a virus. Mumps was a frequent cause of outbreaks among military personnel in prevaccine era. During World War I, only influenza and gonorrhea were more common causes of hospitalization among soldiers. Outbreaks of mumps have been reported among military personnel as recently as 1986. MUMPS VIRUS Mumps virus is a paramyxovirus in the same group as parainfluenza and Newcastle disease virus. Parainfluenza and Newcastle disease viruses produce antibodies that cross-react with mumps virus. The virus has a single-stranded RNA genome. The virus can be isolated or propagated in cultures of various human and monkey tissues and in embryonated eggs. It has been recovered from the saliva, cerebrospinal fluid, urine, blood, milk, and infected tissues of patients with mumps. Mumps virus is rapidly inactivated by heat, formalin, ether, chloroform, and ultraviolet light.