Mumps

Epidemiology of Infectious Diseases: Mumps

Causal agent
Mumps virus - paramyxovirus.

Common clinical features

  • Acute viral illness characterized by fever, headache, tenderness and swelling in one or both parotid salivary glands.
  • Swelling commonly peaks between 1-3 days following infection.
  • In 25% of cases swelling occurs only on one side.
  • 30% of cases in children are asymptomatic.
  • Complications are rare but can include, aseptic meningitis, orchitis (occurs in about 25% of adolescent and adult males and is rare in prepubescent males), oophoritis (occurs in 5% of post pubertal females, mastitis may also occur. Less common complications include pancreatitis, myocarditis, arthritis, thyroiditis, deafness and spontaneous abortion1,2. 

Epidemiology

  • In the UK infections with mumps peaks during the winter and spring.
  • Prior to the introduction of vaccination in 1988 mumps caused epidemics every 3 years with the highest attack rates occurring among children aged 5-9 years1.
  • The HPA has reported a large increase in both notifications and laboratory confirmed cases since 2003, suggesting a marked increase in true infection.
  • In 2004 90% of confirmed cases of mumps occurred among children and young adults over 15 years (an age-group who did not receive the MMR).

Reservoir
Humans

Mode of transmission
Person to person via airborne transmission or droplet spread. Also direct contact with the saliva of an infected person.

Incubation period
16-18 days - range 14-25 days.

Period of Communicability

  • Identified in saliva - 7 days before to 9 days after the onset of parotid swelling. Maximum infectiousness occurs 2 days before to 4 days after the onset of illness.
  • Subclinical infections can be communicable.

Identification
Serology. The mumps virus can be isolated from saliva, blood, urine and CSF in acute phase.

Prevention and control

  • Routine MMR vaccination, 2 doses at 12-15 months and at 4 years of age. There is no upper age limit and where required, two doses can be given separated by at least a one month interval (HPA).
  • Exclusion from school for 5 days from onset of parotid swelling and arrange for laboratory confirmation2. 
  • There is no single antigen mumps vaccine licensed in the UK (HPA).
  • Laboratory diagnosis by oral fluid testing is offered by the Health Protection Agency.

References

  1. Heymann D L, editor, Control of Communicable Disease Manual. 18th ed. American Public Health Association; 2004.
     
  2. Hawker J, Begg N, Blair I, Reintjes R, Weinberg J. Communicable Disease Control Handbook, Blackwell, 2005.

© CM Kirwan 2006