Tetanus is an infectious disease caused by anaerobic bacteria, Clostridium tetani, the spores of which are widespread in the environment.
Under favorable anaerobic conditions, such as in dirty, necrotic wounds or in the umbilical cord if it is cut with a non-sterile instrument, this bacillus may produce tetanospasmin, an extremely potent neurotoxin. This toxin blocks inhibitory neurotransmitters in the central nervous system and causes the muscular stiffness and spasms typical of generalized tetanus which is often manifested as lock jaw. Restlessness, headache, and irritability are common associated symptoms.
The incubation period between exposure to the bacteria and development of the initial symptoms of tetanus ranges from two days to two months, but it's commonly within 14 days of injury.
The disease may affect any age group. As the disease progresses, mild stimuli may trigger generalized tetanic seizure-like activity, which contributes to serious complications and eventually death unless supportive treatment is given. Case-fatality rates are high even where modern intensive care is available.