All horses are at risk for developing tetanus. This is why a good vaccination program is so important. Journal photo.

As American Quarter Horse owners, there are a number of diseases to keep an eye out for and help protect your horse against, such as West Nile virus, Eastern and Western equine encephalitis, rabies, strangles and tetanus. The good news is that tetanus, like the other core diseases, is preventable through a veterinarian-administered vaccination program.

All horses can be at risk for developing tetanus, an often-fatal disease caused by a toxin produced by Clostridium tetani, a spore-forming bacterium present in the digestive tract of many animals and in the soil?. Spores of Cl. tetani can survive in the environment for many years, resulting in an ever-present risk of exposure in horses at equine facilities. Tetanus is not a contagious disease but can be the result of the Cl. tetani toxins entering the horse’s body via puncture wounds, open lacerations, surgical incisions or exposed tissues in unvaccinated horses?.

?Tetanus vaccines are very effective,? said Dr. Tom Lenz, senior director of equine veterinary services for Pfizer Animal Health. ?However, your horses won?t be protected if they are not vaccinated.?

Your horse’s health is important to you. To stay on top of it and keep up-to-date on health information, check out our Common Horse Health Issues report. You?ll find information about strangles, West Nile virus, colic, laminitis, EPM and more!

If tetanus is left untreated, it can be fatal. According to Dr. Nat T. Messer IV, professor in equine medicine and surgery at the University of Missouri College of Veterinary medicine, ??usually 50 to 75 percent of the horses that get tetanus will succumb to the disease, no matter what is done to treat them???.

Wounds and Tetanus

Wound contamination typically leads to infection, as a well-cleaned wound is not likely to result in tetanus. Rather it is usually a wound that contains foreign matter such as soil?.

The incubation period for tetanus is usually one to three weeks. Spores can lie dormant in tissues after wound healing and produce toxins if the local oxygen level drops?. Much of the progression and outcome of this disease depends on how much toxin makes it to the spinal cord?.

Clinical Signs

Tetanus affects the central nervous system of the horse. Once the toxins reach the central nervous system, they stimulate the muscles to extend, and the characteristic muscle spasms begin?. Some of the early indications may include a stiff gait, a raised tail or the horse being reluctant to move.

When the muscles are in spasm, the head and face contract, producing a classic facial expression with ears erect, nostrils flared and a sardonic grin ? the muscles of the lips are pulled back like the horse is smiling, showing his teeth?.

The disease is commonly known as lockjaw, because the jaw muscles become rigid and the horse can’t eat and has difficulty swallowing.

Due to the neurological symptoms such as the stiffness and muscle rigidity, it is important to have a proper diagnosis from a veterinarian, as the disease could be confused with other neurological diseases such as EPM, botulism or rabies.


Proper vaccination by a veterinarian is the best way to help protect a horse from tetanus. Vaccines are currently available with inactivated, adjuvanted tetanus toxoids. Tetanus toxoid vaccines administered per manufacturer recommendations are both safe and effective?.

According to the American Association of Equine Practitioners vaccination guidelines, tetanus is considered a core vaccination. Core vaccinations are those that help protect against diseases that are endemic to a region and that have potential public health significance?. Core diseases include Eastern equine encephalitis, Western equine encephalitis, West Nile virus and rabies. Due to the variations of vaccines on the market, it is important to consult a veterinarian when developing a vaccination program.

If you suspect that a horse has tetanus, notify a veterinarian to confirm the disease.


1. Thomas, Heather Smith. Tetanus in Horses. November 1, 2009. Available at:

http://www.thehorse.com/ViewArticle.aspx?ID=15276. Accessed August 2, 2011.

2. Tetanus American Association of Equine Practitioners. 2008. Available at:

http://www.aaep.org/tetanus.htm. Accessed on June 13, 2011.

3. Core Vaccination Guidelines. American Association of Equine Practitioners. 2008. Available

at: http://www.aaep.org/core_vaccinations.htm. Accessed on June 13, 2011.

From America’s Horse Daily.

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