Also known as infectious or epidemic parotitis, mumps is an acute viral disease caused by a paramyxovirus. It’s most prevalent in unvaccinated children between ages 2 and 12, but it can occur in other age-groups. Infants younger than age 1 seldom get this disease because of passive immunity from maternal antibodies. Peak incidence occurs during late winter and early spring. The prognosis for complete recovery is good, although mumps sometimes causes complications.
The mumps paramyxovirus is found in the saliva of an infected person and is transmitted by droplets or by direct contact. The virus is present in the saliva 6 days before to 9 days after onset of parotid gland swelling; the 48-hour period immediately preceding onset of swelling is probably the time of highest communicability.
The incubation period ranges from 14 to 25 days (the average is 18 days). One attack of mumps (even if unilateral) almost always confers lifelong immunity.
Signs and symptoms
Signs and symptoms of mumps vary widely. An estimated 30% of susceptible people have subclinical illness.
Mumps usually begins with prodromal signs and symptoms that last for 24 hours; these include myalgia, anorexia, malaise, headache, and low-grade fever, followed by an earache that’s aggravated by chewing, parotid gland tenderness and swelling, a temperature of 101° to 104° F (38.3° to 40° C), and pain when chewing or when drinking sour or acidic liquids.
Simultaneously with the swelling of the parotid gland or several days later, one or more of the other salivary glands may become swollen. (See Site of parotid inflammation in mumps.)