HOW DO HORSES GET TETANUS?
Tetanus is an often-fatal bacterial disease caused by the organism Clostridium tetani, which is found in soil and droppings.¹, ² It’s found all over the world and can affect many species, including humans, as well as horses. The bacterium can survive as spores in the environment for long periods of time, and while it is in the soil, it’s harmless. However, the bacterial spore can enter the body through wounds, particularly puncture wounds where there is a lack of exposure of the bacteria to oxygen. The spore then re-activates and multiplies, producing a potentially fatal neurotoxin.
WHY DO I NEED TO VACCINATE?
The tetanus bacteria multiply rapidly in the damaged tissues at the site of the injury. The bacteria produce a powerful nerve toxin, causing distressing symptoms and death in about 80% of cases. If diagnosed early, your vet may treat your horse with large doses of antibiotics, usually penicillin, and administer the tetanus antitoxin injection.² Sadly, however, many owners are still faced with having to euthanase their horse on humane grounds.²
MY HORSES DON’T LEAVE MY PROPERTY, DO THEY STILL NEED TO BE VACCINATED?
Yes. Your horse can be exposed to tetanus even if it does not leave your property. For example, your horse can be exposed to tetanus if it steps on a nail or is punctured by a barbed wire fence. Essentially, the risk of tetanus is pretty much everywhere as the organism that causes it, Clostridium tetani, lives in soil and manure and it enters the body through wounds.¹, ² Horses are particularly at risk because of their environment and tendency to injure themselves.²
THE LABEL SAYS 1-5 YEARS, CAN'T I JUST VACCINATE EVERY 5 YEARS?
The label for Equivac® T suggests that following a first annual booster, vaccination every 5 years may be sufficient. This recommendation is inconsistent with the recommendations of the Equine Infectious Diseases Advisory Board (EIDAB), which has decided that protection for all horses would be more likely if an annual protocol were followed. The EIDAB recommendation is also consistent with recommendations for annual tetanus vaccination in other countries. If a horse is vaccinated at intervals of greater than one year then it would be a good idea to administer a booster dose in the event of an injury occurring.
WHEN SHOULD I ADMINISTER TETANUS ANTITOXIN?
Equivac® TAT is used as a short-term protection in the event of a wound in an unvaccinated horse. If the wound is fresh and the horse has been vaccinated before then a vaccine booster with Equivac® T or Equivac® 2in1 will act rapidly enough to protect the horse. If the wound is a few days old then it may be prudent to administer both Equivac® TAT and a vaccine simultaneously at different sites of injection.
HOW LONG WILL TETANUS ANTITOXIN LAST?
Antibody levels provided by a single 1ml dose of Equivac® TAT containing 1500IU of tetanus antitoxin have been shown to exceed the accepted protective level for 2-3 weeks in the horse.
I HAVE VACCINATED PREVIOUSLY, BUT IT’S BEEN YEARS, DO I HAVE TO START AGAIN?
No, if your horse was vaccinated in accordance with the label at some time in the past, then a single booster should restore protective antibody levels.
CAN I VACCINATE AND ADMINISTER TETANUS ANTITOXIN AT THE SAME TIME?
Yes, a study has been performed that demonstrates no interference with vaccine efficacy if administered simultaneously with Equivac® TAT
1. Hoare R. Horse health – vaccination against tetanus and strangles. PrimeFact 495, June 2007. NSW Department of Primary Industries. www.industry.nsw.gov.au
2. Queensland Horse Council Inc. Tetanus Fact Sheet, May 2010
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