Tetanus - Is your horse vaccinated?
Date: 1 Nov 2025
We have seen some recent cases of tetanus in the region, so we thought it important to remind you about tetanus and the importance of vaccination.
Tetanus is a disease caused by the spores of the bacterium Clostridium tetani, a common inhabitant of the intestinal tracts of animals and found in soil and droppings.
The bacterium can survive as spores in the environment for long periods, and while it is in the soil, it is harmless. However, bacteria can enter the body through wounds, particularly puncture wounds, and through exposed tissues such as the umbilicus of foals and the reproductive tract of post-foaling mares (especially in the event of traumatic foaling or a retained placenta).
Clostridium tetani is an anaerobic organism, meaning it thrives in low-oxygen conditions – such as those found in deep puncture wounds or where the blood supply to tissues has been damaged. However, tetanus can result from any break in the skin that allows the spores to enter the body. In the right conditions, the bacteria are activated, multiply, and release neurotoxins which travel via nerves or the bloodstream to the brain and spinal cord, where they interfere with certain neurotransmitters, resulting in painful muscle contraction and spasms. Horses are the most susceptible of all domestic animals to tetanus toxins.
The progressive muscle stiffness will cause:
- The tail to become stiff and stand straight out
- The ears to stand erect
- Spasm of the jaw (lockjaw), facial “grimace”
- Protrusion of the third eyelid across the eye, especially when the horse is startled.
As the disease progresses, the horse experiences severe pain, is sensitive to light and noise, and has difficulty chewing, swallowing, and moving. The horse will become recumbent, and death occurs when paralysis of the respiratory muscles prevents breathing.
Unfortunately, 80% of horses that contract tetanus will die. Early diagnosis and treatment are critical, but there is no specific cure. Treatment is aimed at killing the bacteria, neutralising the toxins before they bind to the nerves, and supportive care to reduce the severity of the signs while the disease runs its course (this may be days to weeks)
Thankfully, tetanus can be avoided with vaccination.
Horses can be vaccinated from 3 months of age. A primary course consists of two vaccinations 4 weeks apart, then yearly boosters.
Mares should receive a booster 4-6 weeks before foaling to provide foals with early immunity via colostrum.
Dr Catherine Pemberton, Equine Vet
