Bacterial disease caused by a neurotoxin released by the bacterium Clostridium tetani. The bacterium is present in soil and can contaminate wounds. The neurotoxin 'tetanospasmin' leads to muscle spasms and contractions that can culminate in recumbency and asphyxiation.

As the bacterium responsible for the disease has an extremely high prevalence in environments where horses are kept, and because horses are particularly susceptible, regular vaccination against tetanus is essential.