Tetanus is a neurotoxin caused by the bacteria Clostridium tetani, which lives in the soil pretty much everywhere. Clostridium tetani likes to form spores that are very resistant to heat, drying and chemicals. This bacteria can survive for years in the environment. More bad news: it is particularly common in horse manure. You know where you can find plenty of that?
Tetanus becomes a problem when it enters the body, usually through a wound or surgical incision. It is a myth that tetanus comes from sharp metal objects… it’s just that sharp metal objects tend to cause wounds which serve as a perfect entry point for this bacteria.
Once the organism enters the body, it begins to multiply . Clostridium tetani loves anaerobic (oxygen-poor) environments, like the inside of a wound. The tetanus toxin travels through the bloodstream and binds to nerve endings at neuromuscular junctions. The toxin signals the muscle to contract, and the muscle gets locked in the contracted position.
What does Tetanus look like?
• Progressively worse muscular spasms in the limbs with the horse reluctant to move
• Stiffness in the head and limbs
• Muscle spasms in the head and neck with the horse not able to eat or chew properly (hence tetanus may also be referred to as ‘lockjaw’)
• Flaring of the nostrils
• The horse exhibits a startled, wide-eyed expression due to facial muscle spasms
What this looks like is a horse with all 4 limbs stiffened (often called a “sawhorse” stance), and the third eyelid flashing across from the corner of the eye. The horse may be lying down with all 4 limbs extended, unable to stand. Eventually, the tetanus toxin binds to the muscles used to breathe, leading to death.
In short, Tetanus looks very scary. Horses usually begin exhibiting signs within 24 hours of infection. The disease can progress over days to weeks, but is over 50% fatal. In order to survive tetanus, a horse must be rapidly treated with tetanus antitoxin, and managed with intensive supportive care. Even with treatment, horses often have long-lasting deficits from the tetanus infection.
If you suspect your horse may have tetanus, call your veterinarian immediately.
Is my horse at risk?
If your horse’s hooves ever touch the ground, then yes, he is at risk. If your horse lives on a horse farm full of tetanus-laden horse manure, then he is definitely at risk. If your horse lives on a horse farm, goes outside, and has access to sharp objects he could potentially cut himself on (this basically describes every horse I’ve ever met), then he is at high risk for being exposed to tetanus at some point in his life.
In fact, as a human you are also at a pretty high risk of contracting tetanus. This risk is increased if you spend time outside and at the barn, which most of our clients do with most of their free time. If you are a human, you probably received a series of tetanus vaccines as a child. Even so, you will probably receive a tetanus booster vaccine if you have a serious wound and have not been recently vaccinated against tetanus.
How can I prevent Tetanus?
I thought you would never ask! Conveniently, there is a simple, inexpensive vaccine that is very effective at preventing tetanus in horses. Our docs recommended the vaccine twice a year in case your horse suffers a puncture wound or laceration. If we perform a surgery (such as castration) we will want to make sure your horse has been vaccinated against tetanus within the last 6 months. Reminder: that’s not because the docs dip their scalpel blades in Clostridium tetani before your horse’s surgery. It’s because cuts, even clean surgical ones, create a route for this bacteria that lives all around us to get inside the body.
When it comes to tetanus, an ounce of prevention is worth a pound of cure. Since the disease is often fatal, and treatment is very difficult, we feel strongly that it is well worth a vaccine. For this reason, many of the combination vaccines we give include tetanus. In the UK boosters are normally administered every two years – but ensure you check with your vet as products can vary. Tetanus vaccines often give rise to a reaction (swelling) that will disperse
in a few days. If you have any concerns, contact your vet.
in a few days. If you have any concerns, contact your vet.
