Clostridial Diseases in Horses: Understanding, Prevention, and Treatment

Clostridial Diseases in Horses: Understanding, Prevention, and Treatment

Whinny’s Wisdoms

Springhill Equine Veterinary Clinic

Hey everybody, Whinny here! This week I’m talking about a tiny little microscopic thing that can have a huge impact on our equine friends. Clostridial diseases are a group of potentially life-threatening bacterial infections that can affect horses. While these conditions can be rare, they can be extremely dangerous when they do occur. We’ll delve into the world of clostridial diseases in horses, including their causes, symptoms, prevention, and treatment options.

Understanding Clostridial Diseases

Clostridial diseases are caused by a group of bacteria known as Clostridia. These bacteria are commonly found in the environment and in the gastrointestinal tracts of horses, making them a constant risk. When conditions are favorable for their growth, Clostridia can produce deadly toxins, leading to various diseases in horses.

Common Clostridial Diseases in Horses

Springhill Equine Veterinary Clinic

  1. **Tetanus**: Clostridium tetani is perhaps the most well-known clostridial disease in horses. It occurs when the bacterium Clostridium tetani enters the body through wounds or injuries. Tetanus is characterized by muscle stiffness, difficulty swallowing, and spasms. Vaccination against tetanus is a crucial preventive measure, especially since horses are more sensitive than other species to tetanus. It is important to vaccinate horses every 6 months against tetanus.
  1. **Botulism**: Botulism is caused by Clostridium botulinum and can result from the ingestion of contaminated feed or forage. Large round bales and compacted hay cubes or hay bales have a higher risk of becoming contaminated. Horses with botulism experience muscle weakness, paralysis, and difficulty eating or drinking. Immediate veterinary care is essential.
  1. **Malignant Edema/Gas Gangrene**: Clostridial myositis is a serious condition also known as malignant edema or gas gangrene. It can occur when Clostridia bacteria are introduced into the muscle, often due to improper intramuscular injection with Banamine (flunixin meglumine). It results in painful swelling, lameness, and systemic illness.


Preventing clostridial diseases in horses primarily involves vaccination, good management practices, and safe injection techniques:

  1. **Vaccination**: Ensure your horse is up to date with vaccinations for tetanus, botulism, and other relevant clostridial diseases. Consult your veterinarian for the best vaccination schedule.
  1. **Wound Care**: Properly clean and care for any wounds or injuries to minimize the risk of bacterial entry. Maintain a clean environment.
  1. **Feed and Forage Hygiene**: Pay close attention to the quality and storage of feed and forage to prevent botulism. Avoid feeding spoiled or contaminated forage.
  1. **Injection Safety**: Ensure proper injection technique, site sanitation, and needle hygiene to prevent the introduction of Clostridia into muscle tissue. Known how medications are suppiosed to be administered and which medications should be given by a trained professional.

Springhill Equine Veterinary Clinic


If you suspect your horse may have a clostridial disease, immediate veterinary intervention is crucial. Treatment often involves aggressive supportive care, including antibiotics and wound management in the case of tetanus or clostridial myositis. Severely affected horses may require hospitalization.


Clostridial diseases in horses are rare but dangerous. Prevention through vaccination, good management practices, and safe injection techniques is essential. Being informed about the potential risks and early recognition of symptoms can help protect your horse from these life-threatening conditions. Always consult with your equine veterinarian for guidance on vaccination schedules and other preventive measures to keep your horse healthy and safe.

Until next week,


P.S. Did you know that the podcast my docs created, called Straight from the Horse Doctor’s Mouth, is the #1 equine podcast in the world? It’s true! Depending on the day, it’s somewhere in the Top 5 Pets and Animals podcasts on Apple Podcasts, and has been #1 many times. That means it’s beating out all those dog and cat shows! You horse people definitely love this podcast, and I just wanted to say thanks for listening on behalf of the humans here at the Clinic. If you haven’t discovered it yet, you can check it out over on the Podcast Page of my website.

Whinny’s Wisdoms is the official blog of Whinny the Clinic Mouse at Springhill Equine Veterinary Clinic in Newberry, Florida. If you liked this blog, please subscribe below, and share it with your friends on social media! For more information, please call us at (352) 472-1620, visit our website at, or follow us on Facebook!

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More Adventures of the Horse Doctor's Husband
Vaccines: It Really Is Life and Death

Vaccines: It Really Is Life and Death

Tuesdays with Tony


I know this has been said before, but apparently some of you still need reminding: Vaccinate your horses. Every 6 months. By a veterinarian- not something you picked up at the feed store. Don’t skip Rabies, or West Nile, because you’ve owned a lot of horses and you’ve never had one get those diseases. Please humans, for the love! Bonus tip: if your horse has been vaccinated by a veterinarian within the appropriate time period and does contract the disease he was vaccinated against, the vaccine company will probably pay for your treatment costs. Of course, this would be an extremely unlikely scenario, because these vaccines are so incredibly effective. This whole anti-vaccine movement makes me so mad, I could pee outside my litter box!
    Many of these life-threatening diseases are transmitted by mosquitoes. Now, there are 2 ways to protect your horse from such diseases:
    1. Keep your horse indoors in a fully enclosed, air-conditioned, mosquito-free environment 24/7.
    2. Vaccinate.

Seeing as most horses live outside, horse owners usually choose the latter. That’s not to say you can’t work on mosquito control at your farm. Eliminating standing water, installing fans, and fly spray systems are all great ways to cut down on the number of mosquitoes in your barn. But you are never going to be able to prevent your horse from ever being bitten by a single mosquito; and it only takes one bite. Let’s take a closer look at these diseases, to remind us why it’s well worth a few bucks twice a year to protect horses against them.


West Nile Virus

    West Nile Virus is transmitted by a bite from an infected mosquito. The early signs of West Nile are subtle. Your horse may have muscle fasciculations, or twitches, of his face, ears, and neck. He may go off his feed. He may have a fever and act lethargic. You may also notice that he is hyper-reactive to sound, touch, or light. Within a few days, most horses will progress to stumbling, falling down, and being unable to stand. They may go blind. They are often distressed because they want to get up, but their legs are too uncoordinated for them to do so. The rule of thumb with West Nile virus is that once a horse is recumbent, or down, they never get back up. If the horse is not euthanized at this point, his signs will progress to seizures or coma, followed by death.
    Now, on to the treatment for West Nile: oh yeah, there isn’t one. All vets can do is supportive care in the form of IV fluids, anti-inflammatories, nutrition, and slinging the horse to keep it standing. If caught early enough and kept standing, eating, and drinking, about 30% of these horses will survive, but many of them will have lasting neurologic deficits.

Eastern Equine Encephalitis

   This is another mosquito-transmitted disease for which there is no treatment. Some fun facts about Eastern Encephalitis: far and away the most cases of this disease are seen right here in Florida. In fact, we  Floridians have already had 18 cases this year! The EEE vaccine only lasts for 6 months max, so you HAVE to be getting your horses boostered twice a year for this one. Another fun fact: Eastern Encephalitis is almost 90% fatal. This means that no matter how early the signs are noticed, nor how soon supportive care is initiated, the horse is most likely not going to survive longer than 5 days.
    Early signs of Eastern Encephalitis include fever, depression, and going off feed. The condition usually deteriorates rapidly to stumbling, circling, head-pressing, and sometimes blindness. EEE is also called “sleeping sickness,” so named because of the characteristic stance horses tend to adopt during the later stages of the disease. These horses hang their heads low between their legs, often with their tongue sticking out and their eyes nearly swollen shut. From there, many horses become recumbent (there’s our new vocabulary word for the day again), and begin to have seizures or go into a coma. At that point, a decision must be made to euthanize the horse.


   When people think of Rabies, they often think of that dog (ugh, dogs) in Old Yeller. He had one form of Rabies, called the “furious” form. But there is another presentation of Rabies called the “stuporous” form that many owners don’t know about. It is also important to note that an aggressive, lunging, biting, foaming at the mouth horse would be in the late stages of this disease. Earlier, more subtle signs include dysphagia, or difficulty eating, and difficulty drinking or water aversion. The horse may also exhibit neurologic signs such as incoordination, stumbling, circling, and an altered mental status. In the stuporous form of Rabies, these horses will become unresponsive to their environment. With the furious form, horses can become hyper-reactive and even aggressive.
   The single most important thing for you to know about Rabies is that it is contagious to humans, and it is nearly 100% fatal. The Rabies virus is passed through the saliva of an infected animal. This means that even without sustaining a bite, you can get Rabies from an affected horse or other animal just by coming into contact with secretions from their mouth, eyes, or nose. Vaccinating your horses against Rabies is really a no-brainer. Horses live outside amongst several wildlife species that can carry Rabies, such as skunks, bats, foxes, and raccoons. Moreover, by vaccinating your horse against Rabies, you are really protecting yourself and your own family from exposure.


    Tetanus is a recommended core vaccine for horses because most horses have 4 feet in contact with dirt most of the time. Seeing as Tetanus is a bacteria that lives in the soil (definitely all over Florida), horses have an especially high risk for this disease. The Tetanus bacteria can infect a horse through even the tiniest wound. It is a myth that it takes a puncture from a metal object such as a nail to seed tetanus into a wound; any cut or break in the skin or hoof can create an opportunity for tetanus bacteria to enter.
    Tetanus also has a very high mortality rate when tetanus antitoxin is not administered rapidly. The first sign of tetanus is stiffening of the muscles, often first noted in the jaw, which is why this disease is also termed “lock jaw.” From there, all of the horse’s muscles will begin to contract and will be unable to relax. This results in the “sawhorse stance” typical of tetanus infection. Another common sign of tetanus is third eyelid elevation, which means the pink flap at the inner corner of the horse’s eyes becomes prominent. Over a period of only a few days, horses will go down and be unable to stand. Once the muscles of breathing are affected, the horse inevitably dies.

Western Equine Encephalitis

    If we lived on the West coast I would tell you about Western Equine Encephalitis as well, but thankfully we don’t see that disease round these parts. Suffice it to say, this disease is also spread by mosquitoes, and it causes signs very similar to Eastern Equine Encephalitis.
   You may notice a few themes with these diseases:
    1. They all have a high fatality rate. (That’s why we are so hyper about keeping your horses from getting them.)
     2. They are all easily transmitted to horses, either through the bite of a mosquito or other animal, or through the soil.
    3. They all exhibit some pretty horrible signs that you would never want to witness in your horse.
    4.  They are all easily preventable through vaccines.
   We are fortunate that we have vaccines which are extremely safe and effective against all of these core diseases in horses. Now, it is your job as a responsible horse owner to use your noggin and get your horse vaccinated!
   Ok, I’ll get off my cat-box now.
   Until next week,
P.S. Why don’t you check out the Podcast page while you’re here? After you scroll down a bit more and subscribe to this amazing blog, of course. It’s right below my handsome photo in the purple box.

Tuesdays with Tony is the official blog of Tony the Clinic Cat at Springhill Equine Veterinary Clinic in Newberry, Florida. If you liked this blog, please subscribe below, and share it with your friends on social media! For more information, please call us at (352) 472-1620, visit our website at, or follow us on Facebook!

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Everything You Need To Know About Tetanus

Everything You Need To Know About Tetanus

Tuesdays with Tony

A little housekeeping before we get started on Tetanus: don’t forget about my Paddocks & Pastures Seminar on April 19th @ 6:00pm. Join me, the docs, and the Alachua County Extension Office to learn all you ever wanted to know about grass! The talk will be held right here at Springhill Equine, and as always, admission is FREE!

   Now for this week’s enlightening blog. Continuing my trend of why we vaccinate horses for things, I decided to talk to you all about Tetanus today!

What is Tetanus?

   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, chemicals, and fire-breathing dragons. Ok, I got a little carried away there… but seriously, 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? On horse farms!
    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 *evil cat laugh*. 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?

Sawhorse stance tetanus    What this looks like is a horse with all 4 limbs stiffened (often called a “sawhorse” stance), a tight or locked jaw, 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 (read: $expensive$). 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. Better yet, you should call your vet any time your horse suffers a wound that breaks the skin.

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, and this cat has met a lot of horses), 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.
    “But Tony,” you may ask, “humans only need a tetanus booster like once every 5 years. Why do horses need boosters every 6 months?” Well, there are the high-risk factors discussed above (living outside in the dirt, having manure that is naturally full of tetanus). Then there is also the fact that nobody has ever studied exactly how long the protection of a tetanus vaccine lasts in horses. If you have a spare million dollars sitting around, you are welcome to fund such a study. Until then, I’m going to continue to err on the side of caution and recommend you vaccinate your horse once every 6 months.

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 $20 vaccine. For this reason, many of the combination vaccines we give include tetanus. Tetanus is the “T” in “EWT-WN” (Eastern/Western Encephalitis/Tetanus/West Nile) and “EWTR-WN” (Eastern/Western Encephalitis/Tetanus/Rhino virus/West Nile) vaccines. It just so happens that these other vaccines are also recommended every 6 months, so why not lump them all into one poke? If that’s not your style, and this post has inspired you, we do stock the plain Tetanus vaccine at the clinic as well.
    So let’s all remember to call Shannon or MJ at the office to check when our horses are due for a tetanus booster, mmkay? Now I think I’ll go walk through some lovely tetanus-laden horse manure, and roll in some tetanus-flavored dirt! While I’m doing that, why don’t you scroll down a bit and subscribe? I’ll let you take a selfie with me at the next seminar if you do.
Until next week,

Tuesdays with Tony is the official blog of Tony the Office Cat at Springhill Equine Veterinary Clinic in Newberry, Florida. For more information, please call us at (352) 472-1620, visit our website at, or follow us on Facebook!

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