What is the mumps virus?

The mumps virus is a type of paramyxovirus. The virus core contains single-stranded RNA (ribonucleic acid). Exposure to heat, ultraviolet light, formalin, ether, and chloroform can inactivate the mumps virus.1

How is mumps transmitted?

The mumps virus is contagious and acquired by respiratory droplets. Mumps transmission occurs when the saliva or mucus from the mouth, nose, or throat of an infected person contacts another individual by2:

  • Sneezing, coughing, or talking
  • Sharing cups or cutlery
  • Touching surfaces with unwashed hands that are then touched by others

Mumps is most infectious in the several days before and after parotitis onset.1

What are the pathogenesis and clinical features of the mumps infection?

Once a person is infected, the mumps virus replicates in the nasopharynx and regional lymph nodes.1

As with most viral infections, pathogenesis and clinical features usually present in phases: incubation phase, viremia phase, and prodromal phase.

General Clinical Phases of the Mumps Infection1

Phases Characteristics

Incubation Phase

  • Days 12–25 duration from exposure

Viremia Phase (when the virus spreads within the blood)

  • Days 15 to 30 from exposure (3–5 day duration)
  • Virus may spread to and ultimately lead to inflammation of:
    • Parotid glands: causing parotitis as early as 16–18 days from exposure
    • Meninges (outer protective layer of the brain): causing aseptic meningitis
    • Other glands: including salivary, pancreas, testes, and ovaries

Prodromal Phase (early signs and symptoms of disease)

  • Onset may occur days 16–30 from exposure
  • Generally nonspecific symptoms include:
    • Muscle pain
    • Anorexia
    • Malaise (general feeling of discomfort)
    • Headache
    • Low-grade fever

The most common manifestation of the disease is parotitis, occurring in 31%–65% of patients of all ages. The inflammation may affect 1 or both of the parotid gland(s) and may also affect 1 or multiple salivary glands. First signs and symptoms include earache and tenderness in glands along the jaw line. Symptoms decrease a week after onset and may subside 10 days thereafter.1

What are the potential complications of mumps?

In the prevaccine era, common complications of mumps included orchitis, asceptic meningitis, and pancreatitis. In the postvaccine era, most complications have been less than 1%.1

Complications Incidence Rates Details



  • Prevaccine: post-pubertal males
  • In 60%–83% of post-pubertal males, only one testis was affected
  • Characterized by testicular swelling, tenderness, nausea, vomiting, and fever
  • Pain usually lasts for one week but tenderness can persist for weeks

Clinical manifested meningitis


  • Prevaccine
  • Characterized by headache or stiff neck as a result of inflammatory cells in the cerebrospinal fluid
  • Men were at risk three times more than women
  • Symptoms would usually persist about 3–10 days from onset
  • Occasionally encephalitis (acute inflammation of the brain)
  • Mumps-related encephalitis made up 36% of all reported encephalitis in the US in 1967 (0.02%–0.3%)



  • Prevaccine
  • Occasionally occurs without parotitis
  • High blood sugar is transient and reversible

Unilateral deafness


  • Prevaccine



  • From 1966–1971


  • No deaths in recent United States outbreaks

How is mumps diagnosed?

It is highly recommended to take samples from patients that are suspected to be infected by the mumps virus. A mumps diagnosis can be made from the parotid duct, affected salivary gland ducts, throat, urine, and cerebrospinal fluid. The preferred sample is a swab from the parotid gland duct or affected salivary gland duct. Samples should be taken within 3–8 days from the onset of parotitis onset.1

How does geography affect the disease pattern of mumps?

In Temperate Climates, the Incidence of Mumps Cases Seems to Peak In the Late Winter and Early Spring

The incidence of mumps seems to peak in the late winter and early spring.1


No difference in rate of occurrence in tropical climates.3

Downloadable Resource

The resource below has been created to help your patients, their parents, or their legal representatives, learn about mumps while they wait in the doctor’s office.

What you should know about mumps
PDF about mumps that you can download and share with patients, their parents, or their legal representatives.

CDC Disease Information

DISCLAIMER: By clicking on the link below, you will be directed away from to another website. Merck does not review or control the content of the site to which the hyperlink connects; therefore, the hyperlink does not constitute an endorsement by Merck.

CDC, Centers for Disease Control and Prevention



  1. Centers for Disease Control and Prevention (CDC). Mumps. In: Hamborsky J, Kroger A, Wolfe S, eds. Epidemiology and Prevention of Vaccine-Preventable Diseases.13th ed. Washington, DC: Public Health Foundation; 2015:247–260. Accessed January 22, 2020.


  1. Centers for Disease Control and Prevention (CDC). Transmission of Mumps. Updated March 15, 2019. Accessed January 22, 2020.



  1. Rubin SA, Mumps Vaccines. In: Plotkin SA, Orenstein WA, Offit PA, Edwards KM, eds. Plotkin’s Vaccines. 7th ed. Philadelphia, PA: Elseveir; 2018:663-688.

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