Tetanus is a disease of the nervous system. It is a relatively rare disease and if you’ve ever stepped on a nail or had a deep cut that required a doctor’s attention you’ve probably had a tetanus shot yourself. In fact, it’s recommended that you get a tetanus vaccination every ten years. Your horse needs a regular vaccination against tetanus too and this is one of the AAEP recommended core vaccines.
Because horses can be fairly ‘inventive’ about the types of wounds they get and it sometimes isn’t possible to clean a wound immediately after it happens (like when a horse gets a pasture injury after you’ve gone to bed and don’t find it until morning), it just makes sense to protect your horse against this potentially deadly disease.
Other Names for Tetanus:
The old fashioned name for tetanus is lockjaw. One of the symptoms of tetanus is muscle stiffness. The tightness of the muscles makes it hard for the horse (or human) to open their mouth. Clostridium tetanii
Causes of Tetanus:
Lockjaw or tetanus is caused by the bacteria called Clostridium tetani. Outside of the body the spores of the bacteria live in any type of soil, dust or manure. The bacteria from the dirt or manure can enter the body through any wound such as a cut, open burn, surgical incision or puncture in the skin as well as punctures in the soles of the hoof.
Even a small innocuous wound may be an entry point for the Clostridium titanic bacteria. Foals whose dams have not been vaccinated for tetanus can develop tetanus through an infected naval. It is even possible for horses with EGUS to get tetanus by eating contaminated feed. Puncture wounds are particularly worrisome as they are difficult to clean and provide the perfect anaerobic conditions for the bacteria to thrive.
The bacteria enter the wound and there begin to multiply. The powerful toxin (a neurotoxin) that the bacteria produce as they multiply blocks the nerves’ messages to the muscles causing the muscles to tense up.
It may take ten days to two weeks for the symptoms of tetanus to appear. There will be stiffness and the head and neck area, hind quarters and area of the wound may be affected first. The nostrils may be unusually flared. The animal will become progressively stiffer, taking on a ‘saw horse’ stance with head and tail up and will not be able to eat or drink. The horse may become more agitated. Fever may develop with sweating, increased pulse and respiration rate and congested breathing. The nictitating membrane or third eyelid may be seen across the eye. As the horse approaches death the fever can increase.
The mortality rate for horses with tetanus is unfortunately high. Treatment will include cleaning the wound and the area around it thoroughly. Large amounts of antibiotics will be administered in an effort to stop the bacteria’s growth. Tetanus antitoxin will also be administered. For horses still able to eat, food and water should be placed at a height that is easy for the horse to reach.
If you’ve read the popular book War Horse, you’ll know that that horse was also kept in a secluded dark stall to avoid over stimulating it in its already agitated condition. If the horse is unable to stand it may be put in a sling to keep it on its feet. Fluids may be administered intravenously and the bladder may be catheterized. In most case though, humane euthanasia is required.
Tetanus is easily prevented in horses. Your horse should be vaccinated against tetanus at least every two years although as part of the core vaccinations, most people will vaccinate yearly. Foals need to be vaccinated after about four months. If the mare is vaccinated, the foal will receive some protection from the colostrum. Because you work around dirt and manure when you’re with your horse, be sure your tetanus shot is up-to-date as well.
Hayes, M. Horace, and Peter D. Rossdale. Veterinary notes for horse owners: an illustrated manual of horse medicine and surgery. 17th ed. New York: Prentice Hall Press, 1987. Print.