Tetanus in horses is a bacterial infection, where the toxins produced attack the horse’s nervous system. The condition is also known as lockjaw because as the disease progresses, the mouth clamps shut so the animal cannot eat or drink. It is usually fatal. Once a horse is recumbent because of the disease, it is reported that almost 80% of these cases will die. Certainly, it is a far easier disease to prevent by vaccination than it to treat.
At least three different types of deadly toxins are released by the bacterium Clostridium tetani to cause tetanus. Spores of this bacterium are widespread and can be found in dust, manure and soil. These spores enter a wound and given the appropriate conditions, they will germinate into bacteria.
Perhaps surprisingly, a large, cleanish cut is a lower tetanus risk than a small puncture wound. The biggest danger is a deep, festering wound with dead tissue and pus, which is not exposed to fresh air.
Horses and ponies are the most susceptible domestic animal to tetanus. They are readily exposed to the spores while grazing and their predilection for wounds such as lacerations and punctures make them prime candidates for acquiring tetanus.
High-risk situations that are most likely to lead to a horse suffering from a tetanus infection include:
- Puncture wounds contaminated with soil, e.g. kicks
- Stake wounds, because they are often deep and heavily contaminated
- Umbilical infections in the foal
- Castration wounds
- Infections at foaling
Once the Tetanus infection takes hold, the deadly toxins migrate along the peripheral nerves to the brain affecting the nervous system.