Vaccines: It Really Is Life and Death
Tuesdays with Tony
Vaccines
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.
Rabies
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
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,
-Tony
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 SpringhillEquine.com, or follow us on Facebook!
Culicoides (kyōō′lĭ-koi′dēz′) is a species of gnat very common here in Florida. Many horses are actually allergic to the saliva of this gnat, so every bite by one of these annoying little devils sends the poor horse into an itching frenzy. The early signs of this gnat allergy include frequent scratching and hair loss in the ears, mane, base of tail, and chest. Over time the skin in these places will become thickened, there will be multiple open bite wounds, the hair will be completely gone, and the horse will constantly be scratching on anything and everything he can find. Horses with chronic Culicoides hypersensitivity will often develop a “cauliflower ear” appearance over a period of years. Once this happens, the ears will never return to their original shape.
Once the ear has gotten to a point where there is a secondary laceration, abscess, or hematoma, it can be difficult to treat. While we always try conservative options first, these horses sometimes have to undergo surgery under general anesthesia to drain the ear, followed by weeks with the ear taped down against the horse’s head to allow for continued drainage. No fun.
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