A disease caused by the toxin of the bacterium Clostridium tetani that affects the central nervous system , sometimes resulting in death. In the spore form, Clostridium tetani may remain dormant in the soil but infectious for periods longer than 40 years.
Infection begins when the spores are introduced into an injury or wound .
The spores germinate, releasing active bacteria that multiply, and produce a neurotoxin, called tetanospasmin. Tetanospasmin selectively blocks inhibitory nerve transmission from the spinal cord to the muscles, allowing the muscles to go into severe spasm. Spasmodic contractions may be so powerful that they tear the muscles or cause compression fractures of the vertebrae. During these episodes, fractures and muscle tears can occur. The incubation period is 5 days to 15 weeks, with 8 to 12 days as the average.