The mumps virus is an enveloped, single‑stranded, negative‑sense RNA virus in the genus Rubulavirus of the family Paramyxoviridae. It primarily infects humans and causes mumps, an acute systemic illness best known for painful swelling of the parotid and other salivary glands.
Virology & Pathogenesis
Mumps virus has a nonsegmented RNA genome that encodes six structural proteins (nucleoprotein, phosphoprotein, matrix, fusion, hemagglutinin‑neuraminidase and large polymerase) and several accessory proteins that modulate host immunity. As a member of the Paramyxoviridae family, it is an enveloped, negative‑sense RNA virus that replicates in the cytoplasm. Viral attachment is mediated by the hemagglutinin‑neuraminidase glycoprotein, which binds sialic acid residues on respiratory epithelial cells, and membrane fusion is executed by the F protein. Mumps virus is transmitted via respiratory droplets or direct contact with saliva or fomites. Some infected individuals—up to one‑third—are asymptomatic but still contagious. Peak infectivity occurs a few days before parotitis develops, while the virus replicates in the upper airways. Once inside the host, the virus replicates locally and then spreads to regional lymph nodes and the bloodstream, causing viremia. It disseminates to multiple organs, leading to inflammation of the central nervous system, salivary glands, pancreas, testes or ovaries, and mammary glands. Vaccination, introduced in 1967, reduced mumps incidence by 99.8% in the United States.
Clinical features and prevention
Mumps typically presents with a nonspecific prodrome of fever, headache, myalgia and malaise followed by parotitis, which occurs in about 70% of symptomatic infections. Parotid swelling is often bilateral, and inflammation may extend to the submandibular and sublingual glands. Complications include orchitis and oophoritis, leading to transient infertility, pancreatitis, meningitis, encephalitis, hearing loss and, rarely, spontaneous abortion during pregnancy. Aseptic meningitis occurs in up to 10% of cases, and sensorineural deafness is a rare but serious sequela. Diagnosis is primarily clinical but can be confirmed by reverse transcription PCR or serology. Treatment is supportive, consisting of rest, hydration and analgesia; there are no specific antivirals. The live attenuated measles‑mumps‑rubella (MMR) vaccine is highly effective and provides long‑lasting immunity. High vaccination coverage is critical to prevent outbreaks, as waning immunity and vaccine hesitancy have led to periodic resurgences on college campuses and among under‑vaccinated populations.
Mumps virus remains a vaccine‑preventable cause of parotitis and systemic illness. Maintaining immunization programs and rapid identification of cases help control this contagious virus.
Related Terms: Rubulavirus, Parotitis, MMR vaccine, Orchitis, Paramyxovirus