Mumps Virus Overview and Epidemiology

Mumps Virus Overview

• Mumps is a viral illness caused by the mumps virus, part of the Paramyxoviridae family.
• The virus causes acute viral parotitis, painful swelling of the parotid glands.
• The mumps virus is closely related to parainfluenza virus type 2.
• Mumps, like measles, is highly contagious, affecting only humans.
• Humans are the only source of the virus, with transmission favored by asymptomatic infections.

Epidemiology

• Mumps outbreaks can occur, with unvaccinated individuals at higher risk of infection.
• Vaccinated people typically exhibit milder symptoms and fewer complications.

Morphology

• Mumps virus is spherical, ranging in size from 100 to 250 nm.
• It is a single-stranded RNA virus.
• The nucleocapsid is surrounded by a lipid envelope.
• The virus has HN and F proteins.

Pathogenesis

• Over a third of mumps infections are asymptomatic.
• Transmission occurs through person-to-person contact via respiratory droplets.
• The virus infects respiratory tract epithelial cells and spreads through the bloodstream (viremia).
• Infection can affect the parotid glands, testes, and central nervous system.

Clinical Features

• Mumps is an acute illness characterized by non-suppurative enlargement of one or both parotid glands (salivary glands).
• Typically, mumps causes mild childhood disease, but in adults, complications such as meningitis and orchitis (inflammation of the testicles) are more prevalent.

Symptoms

• The primary symptom is swelling of the parotid glands.
• Symptoms include fever, headache, pain while chewing or swallowing, loss of appetite, and general weakness.
• The incubation period is typically 12-25 days.
• Systemic conditions may include enlargement of the testicles in men and pelvic pain in women.
• Other possible conditions include aseptic meningitis, meningoencephalitis, pneumonia, deafness, pelvic pain, and orchitis.

Laboratory Diagnosis

• Lab studies are generally not needed for typical cases.
• The mumps virus was isolated in embryonated eggs in 1945 and in cell culture in 1955.
• Clinical specimens (saliva, cerebrospinal fluid (CSF), and urine) are collected soon after symptom onset.
• Specimens are inoculated into monkey kidney cell cultures, or human amnion/HeLa cells.
• Isolation can take 1-2 weeks. Cytopathic changes are not reliable.
• Serological diagnosis (ELISA, immunofluorescence) is useful.
• Molecular diagnosis using PCR is also available.

Treatment

• No specific treatment for mumps is available.
• MMR (measles-mumps-rubella) live virus vaccine is used for prevention.
• Drinking water or juice helps prevent dehydration.

Prevention and Control

• Vaccination with a live mumps vaccine is the main preventative measure.
• Avoid sharing utensils, drinking glasses, etc., with an infected person.
• Limit close contact with sick individuals.
• Cover coughs and sneezes with a tissue to prevent the spread of the virus.
• Wash hands regularly, particularly before eating and after handling potentially contaminated objects.
• Use alcohol-based sanitizers or soap.