Mumps is an acute viral infection caused by mumps virus, a paramyxovirus that primarily infects the respiratory tract and can spread systemically. The illness is classically associated with painful swelling of the parotid salivary glands, producing swelling around the cheeks and jaw, although some infections are asymptomatic or produce nonspecific symptoms. Mumps spreads between people through respiratory secretions and close contact. Vaccination substantially reduces the incidence and severity of disease but does not provide absolute protection against every infection.
After entering through the respiratory tract, mumps virus replicates locally and then disseminates to other tissues. The incubation period is generally around two to three weeks, after which fever, headache, malaise, muscle aches and reduced appetite may develop. Parotitis can appear subsequently, often affecting one or both sides. Swelling typically makes the angle of the jaw less distinct and may cause pain during chewing or swallowing. Because not every infected person develops obvious parotid swelling, laboratory testing can be important when the diagnosis is uncertain or outbreak surveillance is required.
Mumps can involve organs beyond the salivary glands. Orchitis, inflammation of the testicles, is an important complication in post-pubertal males and can cause significant pain and swelling, although permanent infertility is not an inevitable consequence. Oophoritis and mastitis can occur less commonly. Neurological complications include aseptic meningitis and, more rarely, encephalitis. Pancreatitis can also occur. Hearing loss is an uncommon but potentially permanent complication. The likelihood and severity of complications vary with age and individual circumstances.
Diagnosis may be suspected clinically when compatible parotitis occurs, particularly during an outbreak, but several other conditions can cause facial or salivary-gland swelling. Reverse-transcription polymerase chain reaction testing of an appropriate specimen can help detect viral RNA, while serology may provide additional evidence depending on timing and vaccination status. A negative test does not automatically exclude disease because specimen timing and collection technique affect sensitivity. Public-health authorities may recommend isolation and contact management because infected individuals can transmit the virus before or around the onset of parotitis.
Prevention relies principally on vaccination with measles, mumps and rubella vaccine. Protection is strong but not complete, and outbreaks can occur among highly vaccinated populations, particularly where immunity has declined or where close-contact settings facilitate transmission. Maintaining high vaccine coverage reduces both the frequency of infection and the likelihood of large outbreaks. Vaccination is not a treatment for established mumps infection, although ensuring that susceptible contacts are appropriately vaccinated may contribute to future protection.
Treatment is primarily supportive because there is no routinely used antiviral therapy that eradicates mumps virus. Management may include rest, adequate fluid intake and analgesic or antipyretic treatment when appropriate. Complications such as severe orchitis, meningitis or encephalitis require clinical assessment and may require hospital care. Aspirin should not be given to children or adolescents with viral illnesses because of the association between salicylate use and Reye syndrome.
Mumps is often confused with other causes of parotitis, including bacterial infection, autoimmune disorders and obstruction of salivary ducts. It is also sometimes assumed that vaccination makes infection impossible, whereas vaccines substantially reduce risk without guaranteeing complete individual protection. Mumps is different from measles even though both are included in the combined MMR vaccine. Their viruses, clinical presentations and characteristic complications differ. Accurate identification is particularly important during outbreaks because public-health measures depend on correct recognition of cases and contacts.
The public-health importance of mumps lies in its capacity for rapid spread in schools, universities, military environments and other close-contact settings. Surveillance helps identify outbreaks and assess whether apparent cases represent mumps or another cause of parotitis. Vaccination programmes have dramatically reduced disease compared with the pre-vaccine era. Continued outbreaks demonstrate the importance of maintaining population immunity and recognising that vaccine-preventable diseases can persist when susceptible individuals accumulate or when exposure intensity is high.
