Mumps

Mumps

 

Mumps is an acute, generally self-limiting, contagious disease of short duration.

Epidemiology

  • Prevalence – from 2001 to 2003, fewer than 300 cases in U.S.
    • Since 2003 – several outbreaks involving >1,000 people
  • Incidence has decreased greatly since the MMR vaccine was licensed in 1971; this vaccine protects patients against measles, mumps and rubella
  • Age – highest incidence is found in 16-24 year olds
  • Transmission
    • Infections are transmitted by droplets spread from the upper respiratory tract

Organism

  • Family – Paramyxoviridae; genus – Rubulavirus
  • Mumps virus is an RNA virus
  • Immunity after infection appears to be lifelong
    • Silent re-infections occur infrequently

Clinical Presentation

  • The incubation period for this RNA virus is 18-21 days
    • 25-30% of all infections are silent
  • Bilateral or unilateral parotitis is the most common clinical feature; 60-70% of infections
  • Secondary involvement of testes (orchitis), ovaries (oophoritis), central nervous system (aseptic meningitis, encephalitis) and, rarely, the pancreas, peripheral nervous system, eye, inner ear and myocardium (myocarditis)
    • Testicular involvement, particularly in teenagers, can lead to infertility or decreased fertility

Diagnosis

  • Generally diagnosed by clinical presentation
  • Laboratory testing
    • Culture  – saliva, throat, urine and cerebrospinal fluid
    • Appearance of an IgM antibody response normally occurs 7-14 days after the onset of disease
      • IgM antibody response may be delayed or absent in previously vaccinated patients and the period of viral excretion may be shorter
    • Assays for IgM are more useful than IgG assays for acute infections, since cross-reactions have not been observed with IgM
      • Cross reactivity can occur with assays for IgG, particularly due to parainfluenza 1 and 3
    • IgG antibody levels induced by vaccine are lower than that from natural infection

Differential Diagnosis

  • Viral – parainfluenza type 3, influenza A, coxsackievirus, Epstein-Barr virus, adenovirus, herpesvirus, HIV
  • Bacterial parotitis – unilateral
  • Parotid gland neoplasm – unilateral

Treatment

  • Supportive

Prevention

  • Preventive strategies include MMR vaccine which is 75-90% effective
  • Mumps is uncommon in the U.S., secondary to current vaccination programs
  • Administer vaccine to infants (12-15 months of age) with revaccination of children (between 4 and 12 years)
  • Since the vaccine is a live attenuated virus, it is not recommended for patients who are:
    • Significantly immunosuppressed (e.g., HIV, cancer, chronic corticosteroid therapy)
    • Allergic to gelatin (component of the vaccine)
    • Pregnant

See Also