Tetanus

Epidemiology of Infectious Diseases: Tetanus

Causal agent
A neurotoxin produced by the bacterium Clostridium tetani.  

Common clinical features
Characterized by generalized increased rigidity and convulsive spasms of skeletal muscles. The muscle stiffness usually involves the jaw (lockjaw) an neck and then becomes generalised 1,2.

Case fatality rate ranges from 10-80% and is highest among infants and the elderly1.

Epidemiology

  • Worldwide - present in the environment.
  • In 2001 an estimated 282,000 died worldwide from tetanus, mostly in Asia, Africa and South America.
  • The incidence of tetanus in the UK decreased following the introduction of national tetanus immunisation in 19612.
  • Between 1984 and 2002, there were 186 cases of tetanus in England and Wales, of which 74% occurred in individuals aged over 45 years2.
  • Neonatal tetanus is an important cause of mortality in many countries in Asia and Africa due to infection of the baby's umbilical stump.

Reservoir
The gastrointestinal tract and faeces of horses and other animals, including humans.

Tetanus spores are found in soil contaminated with animal faeces.

Tetanus spores are ubiquitous in the environment.

Mode of transmission
When tetanus spores are introduced into the body through a puncture wound contaminated with soil, street dust human faeces or by injecting drug use, and occasionally through abdominal surgery1.

Person to person spread does not occur.

Incubation period
3-21 days, range 1 day to several months.
Most cases occur within 14 days1.

Period of Communicability
No direct person to person transmission. 

Prevention and control
Immunization with tetanus toxoid. A Total of five doses of tetanus toxoid containing vaccine at the appropriate intervals are considered to give lifelong immunity2.  

References

  1. Heymann DL, editor, Control of Communicable Disease Manual. 18th ed. American Public Health Association, 2004.
     
  2. Salisbury DM, Begg NT.  Immunisation against infectious disease (The green Book). London: HMSO, 1996. Available at http://www.dh.gov.uk/assetRoot/04/07/29/84/04072984.pdf

© CM Kirwan 2006