Mumps Pathophysiology and Clinical Manifestations

Causative Agent and Transmission

Mumps is caused by the mumps virus, a member of the Paramyxoviridae family, and transmission occurs primarily through respiratory droplets or direct contact with infected saliva, with an incubation period averaging 16-18 days after exposure 2
Patients are contagious from approximately 7 days before through 8 days after the onset of parotid gland swelling 4

The virus demonstrates particular tropism for salivary glands, especially the parotid glands, gonads, pancreas, and meninges 1, 2, 5
Parotitis, the hallmark of mumps infection, occurs in 60-70% of infections and can be unilateral or bilateral, preceded by prodromal symptoms including fever, headache, malaise, myalgia, and anorexia 2, 3
Asymptomatic infection occurs in approximately 15-20% of infections, while nonspecific or respiratory presentation occurs in up to 50% of infections 2
Neurological complications, including aseptic meningitis and meningoencephalitis, can occur in approximately 4-6% of clinical cases, with potential for permanent sequelae 2
Orchitis, inflammation of the testes, occurs in up to 38% of postpubertal males, while oophoritis, inflammation of the ovaries, can occur in postpubertal females 2, 5, 6
Pancreatitis and hearing loss are also potential complications, with hearing loss being a major cause of sensorineural deafness among children in the pre-vaccine era 2, 5

Inapparent infection is more common among adults than children, while parotitis occurs more commonly among children aged 2-9 years 2
Severity of disease generally increases with age, and women who develop mumps during the first trimester of pregnancy have an increased risk for fetal death 1, 2

Infection or vaccination typically confers long-lasting immunity, but waning immunity can occur over time, particularly with vaccine-induced immunity 6
Vaccine effectiveness is approximately 88% after two doses, and the most effective prevention is through vaccination with the live attenuated mumps vaccine, typically administered as part of the MMR vaccine 2, 4, 7
Two doses of the vaccine are recommended for optimal protection, and vaccination has reduced mumps incidence by 99% in the United States since its introduction 2, 4