Tetanus in Horses
Every year there are cases of tetanus in horses but this is a disease which is entirely preventable. A safe, affordable and highly effective vaccination is available and so this disease really should be a thing of the past. But it isn’t!
The disease is caused by the toxins which are released by the bacterium Clostridium tetani. This bacterium is common and its spores can be in dust, manure and soil. If the spores enter a wound on a horse and find the right conditions they will germinate into bacteria. Surprisingly a dirty cut of significant size is a lower tetanus risk than a small puncture wound. The bacteria thrive in deep wounds which are not exposed to the air.
So, it is puncture wounds, castration wounds and stake wounds that represent the greatest danger and equines are highly susceptible to tetanus.
What is Tetanus?
This disease is also known as lockjaw because as it progresses, the horse's mouth clamps shut. This prevents them from eating or drinking. The infection produces deadly toxins which travel through the nervous system to the brain. Horses become stiff, suffer muscle spasms and will be sensitive to stimuli.
The incubation period varies and depends on the distance the toxins have to travel from the wound to the brain. Tetanus can develop within a couple of days of infection or take several weeks to appear. The shorter the incubation period, the more serious the disease tends to be.
The early signs of tetanus are generally a higher sensitivity to touch and sound, a stiff gait, prolapsed third eyelids, a rigid tail and rigid ears. The horse will also exhibit a concerned expression and flared nostrils. Eventually they will not be able to open their mouth. Food and water may be regurgitated via the nostrils and the horse will drool when it becomes difficult to swallow.
The disease will progress to an even more distressing stage when the horse suffers more dramatic spasms and convulsions. Death is generally the result of respiratory failure and dehydration.
Tetanus is usually straightforward to diagnose due to the very obvious and highly distressing symptoms together with the presence of a wound. If you observe the symptoms of tetanus it is crucial to call the vet immediately. Around 75% of infected horses will not survive the illness. Horses that survive tend to be the ones that receive treatment early, but treatment is costly.
You should ensure that your horse receives vaccination against this unpleasant disease. A primary vaccination should be followed by boosters every two or three years. Vaccinated pregnant mares should have a tetanus booster four to six weeks prior to foaling. This ensures that the foal receives maximum protection from the antibodies in the colostrum (first milk).
Foals usually start their vaccination programme at approximately four months of age. Foals of unvaccinated mares or those who do not receive adequate colostrum for any reason should be given tetanus antitoxin at birth.
If you invest in a horse and its history in unclear, vaccinate them as a priority.