Eastern Equine Encephalitis

Eastern Equine Encephalitis

Tuesdays with Tony

Eastern Equine Encephalitis  

 

So I was scrolling through Facebook the other day (I may have hacked one of the docs pages, one day maybe they will let me have my own page) but to my surprise I came across a post about horses and people in Florida becoming infected with Eastern Equine Encephalitis. I was shocked and frankly a little scared! I have heard everyone around here talk about the dreaded “triple E” before and I even think we had a few cases come through the clinic last year. Nonetheless, reading about it being so close to home yet again, made me realize just how lucky I am that cats don’t get EEE.

 

What is EEE?

 

Eastern Equine Encephalitis, sometimes referred to as “Sleeping Sickness”, is a viral disease that affects birds, horses and humans. It typically occurs on the eastern half of the United States and more specifically in the southeast. “Encephal” means head or brain, and “-itis” means inflammation, therefore, the virus that causes EEE results in inflammation of the brain in both humans and horses. Birds typically are not affected by the disease and just carry it, although the exception to this is Emus.

 

How is EEE Transmitted?

 

Mosquitoes, what are they even good for? All they do is buzz around, bite us, cause horrible itchy skin, and spread nasty diseases. These little suckers are the main transmitters of EEE. A mosquito bites a bird that is a carrier of the virus. The mosquito then bites your horse (or you) and transmits the virus. Don’t you just wish we could wash mosquitoes mouths out with soap? Lucky for most birds and mosquitoes, the virus typically does not affect them, they are just the carriers and transmitters of the disease. However, once an infected mosquito bites you or your horse, the whole story changes. A horse that is infected with EEE cannot, however, spread the disease to another horse, or to a human, and humans cannot spread the disease to horses. Basically, transmission of the virus is the fault of birds and pesky mosquitoes. 

Springhill Equine Veterinary Clinic

Clinical Signs

 

90% of horses and 35-50% of humans that become infected with EEE will die from the disease. Once a horse is bitten by an infected mosquito it takes 7-21 days before clinical signs appear. An infected horse may initially show signs of depression, fever, increased heart rate, decreased appetite, and drooping of the eyes and lips, hence the term “Sleeping Sickness”. Clinical signs can eventually progress to weakness, erratic behavior, and seizures which can lead to your horse laying down and not being able to get back up. 

 

Treatment

 

As an honorary doctor, my favorite thing about my job is the successful treatment of an ill patient. Sadly, EEE does not have a specific treatment, and supportive treatment is often unsuccessful. It hurts my kitty heart when I hear about a horse who has had to suffer through the effects of EEE. Of course, myself and the docs here will do all that we can for a horse who has contracted EEE. 

The goal of supportive care is to treat fevers associated with EEE, and this is usually accomplished with the use of NSAIDs. Often times, horses with EEE will be placed on intravenous fluids and may require nutritional support as they typically have a hard time drinking and eating on their own. 

Once a horse reaches the point of the disease where they lay down, it is unlikely they will stand back up. When they are down they can thrash and cause self-inflicted trauma. Slings have been used on occasion to assist a down horse back into the standing position, however, horses with EEE are typically in a comatose state and the use of a sling is widely unsuccessful. Since EEE is a virus, no kind or amount of antibiotics will be useful in treatment. Often, humane euthanasia is elected by owners to prevent their horse from further suffering. 

 

Prevention

 

Fortunately, there is an extremely effective vaccination against EEE. As you are all well aware by now, my docs here are sticklers for upholding the highest standard of care for your horses. This includes the EEE vaccination which is also considered a “Core Vaccine”. What is a “Core Vaccine” you ask? Well, it is a vaccination that is vital to keeping your horse healthy and protected from diseases they are at risk for. 

Here at the clinic we use a combination vaccine that will provide your horse protect from 4 or 5 of the common diseases they are exposed to. You may hear the docs or technicians refer to the vaccine being administered to your horse as the EWT/WN or EWTR/WN.  All these letters can get very confusing at times. EWT/WN stands for Eastern encephalitis, western encephalitis, tetanus, and west nile, where as EWTR/WN includes all of the above plus the rhinopneumonitis vaccine.  

These vaccines are given at least every 6 months. Horses that travel often or are in many competitions during the year may receive the EWTR/WN vaccine 3 times a year. The most important thing to remember is that mosquitoes are present in Florida all year long! Because of this, twice yearly vaccinations against the mosquito-borne illnesses including EEE and West nile are imperative to your horse’s health and frankly, their life. 

It is definitely mosquito season and there have been reports of EEE all around the area, so if you think you might be behind on getting your horse vaccinated, give me a call at the clinic and we will get you on the schedule and your horse up-to-date.  

 

Until next week,

~Tony

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!

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Rabies

Rabies

Tuesdays with Tony

Rabies

This week I’m starting with the condensed version of things. Rabies can look like just about anything neurologic, from a little bit quiet, to raging maniac. It can also look like a wound that won’t heal, and is super itchy. Oh, and it can also look like a mild colic that doesn’t respond to Banamine. Even better, you can get Rabies from your horse. The answer? VACCINATE your horse for Rabies. And your dog, and cat, too! And now, the rest of the story.

If you’re a mammal, you can get it

Rabies is an interesting virus. Lots of them are, but Rabies is really good at getting itself passed around. To start with, it only infects mammals, but it does a pretty good job being able to infect all of them. From rats, to foxes, to dogs, cats, and elephants, they all have the potential to get Rabies. Once an animal is infected, it usually takes between three and eight weeks to show symptoms. BUT, and it’s a huge but, it can take a really, really long time for symptoms to show up, like months, and in rare cases, years. Rabies has to travel from the point of entry to the brain before it starts wreaking havoc, and the immune system is fighting it the entire way. This means if an animal gets infected by a bite at the tip of its tail, it’s going to be a long time before it makes it to the brain. Know what keeps it from getting to the brain? A vaccinated animal! Know who makes sure your horse gets all the right vaccines at the right time? My Docs!

Rabies in Da House!

I’m not gonna lie, I find it fascinating what teanie, tiny viruses can do to make sure they live, and reproduce. Now that the Rabies virus has made it to the brain, it’s going to change the behavior of the animal to increase the chances it gets passed around. How crazy is that?!? I mean, I’ve changed the behavior of my humans so it’s more to my liking, but I’m a wickedly intelligent cat. This is a virus. You can’t even see it with a microscope. While signs of rabies can start out pretty varied, almost all infected animals will go through these next phases at some point. The virus will make them start drooling. This is brilliant because the virus is concentrated in the saliva. What better way to spread yourself than make more drool? 

Springhill Equine Veterinary Clinic

Next, the virus makes the animal lose its fear. This means that wild fox is faster to come up to you and act tame. Or, if no humans are around, go after a horse like you see in this video https://www.facebook.com/TCEESFL/videos/1985117155060876/   The fear of water thing is a bit of a myth, but nearly all of them will get aggressive at some point. Which makes sense. This aggression drives them to attack and bite other animals, and then the virus gets to live another day, in another animal. Know what prevents this? A properly vaccinated animal. 

What’s with the crazy quarantines?

Because rabies can be given to humans, the Health Department takes quarantine and testing very, very seriously. My Docs recommend calling your local Health Department if you have an animal you think may have rabies.They will work with animal control, and/or local veterinarians to capture and test the suspicious animal. They will then quarantine your animals, and your property for the safety of everyone else. You don’t want to be the one responsible for spreading rabies to everyone in your neighborhood, do you? Pretty sure that would get you unfriended in real life as well as the Face thingy. 

If your animals are vaccinated by a veterinarian, that quarantine will only be 10 days. I know none of you would vaccinate your animals any other way, because you know your veterinarian is the best way to make sure the vaccines are handled and administered properly, but we all have weird friends and relatives. If you vaccinated your animals, or, even worse, if they aren’t vaccinated at all, that quarantine could be as long as 6 months, because of the potentially long incubation time I talked about earlier. Seems like cheap protection to have your veterinarian properly vaccinate your horse. 

Speaking of Vaccines

I hear this one all the time: my dog and cat get vaccinated for rabies every three years. How come my horse gets it every year? Because your horse is really bad at responding to the vaccine, that’s why. Horses are really bad at the important things like digestion, good support structure, and responding to vaccines. Extensive research shows that horses are protected by the vaccine for 14-16 months. That’s not a spectacular response time. And that’s why your horse should get one every 12 months. Rabies vaccines are also only recognized by the powers that be when administered by a veterinarian. Again, I know you would never administer your own vaccines, but there’s the weird friends and family to think about. 

Back to where I started. Make sure your horse is vaccinated for rabies yearly, and report weird wildlife behavior. 

Now be a well-behaved, non-rabid human and scroll down to the subscribe button. If you subscribe, you get my blog a day early, and you never miss my wisdom and charm. 

Until next week,

~Tony

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!

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Vaccines: It Really Is Life and Death

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!

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Encephalitis: Mosquitoes and their Nasty Viruses

Encephalitis: Mosquitoes and their Nasty Viruses

Tuesdays with Tony

Eastern Equine Encephalitis

It’s been a rough two weeks around here. My Docs have diagnosed three horses with Eastern Equine Encephalitis (EEE). Two of those were very healthy, well cared for horses which helped them defy the odds, and survive the virus. The third horse, unfortunately, had to be euthanized. Ninety (yes, ninety) percent of horses who get EEE die or are euthanized. Being a cat, I’m not one to mince words, but I’m really not going to here. It’s a horrible way to die. They get super-high fevers, they get massive headaches, and, after as little as 12 hours, they start having seizures. Once they start having seizures it can be impossible for my Docs to even euthanize them.

Horrible, awful, no good mosquitoes

EEE normally goes about life happily going from birds, to mosquitoes, to birds, and round and round. This works well for EEE. Birds (most of them anyway) don’t get sick or die from the virus, and mosquitoes make an excellent delivery vehicle as they fly around being annoying. However, if one of these mosquitoes carrying Encephalitis bites a horse or human, the story changes dramatically.

The key to remember here is that a mosquito is carrying the virus to your horse. All that’s needed is some water (we’ve got lots of that in Florida), some mosquitoes (we probably have more mosquitoes than water in Florida), some birds, and some EEE virus. Your horse doesn’t even have to leave the farm to get sick. No other horse has to come visit to bring the virus. It comes to you just like a pizza delivery.

EEE Springhill Equine Veterinary Clinic

Is EEE everywhere?

Yes, it’s everywhere in Florida. If you want to know just how everywhere it is, click here. Each week the State of Florida posts an update about the prior week’s mosquito-borne virus activity. Personally, it’s what I’m checking out while it appears I’m sleeping on the keyboards around here. Did you know the State has sentinel chicken flocks? These are chickens that get a little bit of blood taken every week. This blood is tested for EEE, WNV, and a bunch of other viruses to see if the chickens have been exposed. Watching these flocks helps people like my Docs know if Encephalitis or West Nile Virus is active in an area. You can see some crazy stuff on these reports! This past week a person in Taylor county tested positive for EEE!!!

Wait… Humans can get it too?

Yep. I said it earlier, but you might have been distracted as you humans are prone to do. The good news is not every horse or human will get sick. The DNA that particular horse or human has is a key factor in how they respond. If they have an immune system that lets the virus get into the brain and spinal cord, that’s really bad. If the immune system then recognizes the foreign invader and goes after it with all-out warfare, that’s really, really bad. The immune system likes to respond with a nuclear annihilation-level response. That response inside the brain and spinal cord causes a lot of swelling. Swelling inside the skull doesn’t go very well.

Vaccines save lives

Great news: there’s an easy, inexpensive way to save your horse from the agony of EEE. Vaccinate. It’s so easy even a dog can understand it. For the average horse, twice-yearly vaccination for EEE will give them good protection. For youngsters, old guys, and anyone else who may have a stressed immune system, every 4 months is a better plan. This vaccine works! My Docs have even made it easy to know if your horse is protected with their Wellness Plans. In fact, Eastern Equine Encephalitis is one of the biggest reasons the Wellness Plans exist. My Docs want to make sure every horse is well-vaccinated against this horrible virus, so they came up with a plan that made it easy for you horse owners to stay on schedule. Sure, it’s a shameless plug for the Wellness Plans, but this is one of the many reasons Wellness is fantastic!

We live in the land of mosquitoes and water, which means EEE has the perfect environment to live the good life. Be a good human. Vaccinate your horse so they don’t get this horrible virus.

Now be an even better human and scroll on down and subscribe to my blog. Weekly Tony wisdom for free: You can’t beat that!

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

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 SpringhillEquine.com, or follow us on Facebook!

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Why Equine Vaccines Are Only Good For Six Months

Why Equine Vaccines Are Only Good For Six Months

Tuesdays with Tony

Yeah yeah, I know I just talked about this, but today I want to answer the question I get ALL THE TIME: Do I really have to give vaccines every every 6 months? Yes. Yes you do. If you need more than my assurance, then read on.

When the immune system attacks

That’s exactly how the horse immune system works. My Docs give vaccines, and your horse’s immune system responds great. By that, I mean it makes antibodies to the diseases the vaccines were for. Those antibodies roam around the body 24/7/365 looking for their target (like Eastern Equine Encephalitis, EEE for short). When they find their target, they attack and fight to the death. When something like EEE attacks, it doesn’t attack with two or three little viruses. It attacks with millions of viruses, which means the body needs millions of antibodies. Even more important in a state like Florida with EEE out there all the time, the body needs to have millions more antibodies ready for the next attack.

There’s something I was supposed to be doing…

That last part is where horses have trouble. You see, the immune system needs to remember what viruses it’s supposed to make antibodies to. The equine immune system suffers from short term memory loss. My Docs give a vaccine, those millions of antibodies get made for a while, then the body starts to forget. That time frame is about 6 months. In some horses, it’s as short as 4 months! A bunch of researchers have vaccinated horses, then checked the blood every month for 6 months to see how many antibodies there are floating around. Turns out that number drops in a big way at 2 months, then does a slow decline over the next few months. Here’s a link to one of these papers, in case you need to read it for yourself. The important thing to note in this paper is that these horses were routinely vaccinated every 6 months for YEARS before this study came out. ← And that’s why horses have to get vaccinated all the time, even when they’ve had them for years.

Can’t you do a blood test?

My Docs often get asked, What if we run a blood test to see if there are enough antibodies? You may not realize it, but that’s a super-complicated question. Until recently, it was tough to find a lab that would run these blood tests, called titers. We do now have a lab at Kansas State University where Eastern Encephalitis, West Nile, and Rabies titers can be run. Next tricky part is deciding how many antibodies are enough. No one really knows. There was some work done many, many years ago to look at how much was enough. However, by today’s standards, the answers they got give us an OK answer, but not a very definitive one.

So yes, for some diseases, a titer can be done, but the answer may still be a big question mark.

Is this true for all equine vaccines?

Pretty much, yep. Horses just don’t respond well to vaccines. They do about the best with Rabies, but even then those antibody numbers drop hard and fast at about 14 months. Rhinopneumonitis (also called Herpes, Rhino, or EHV-1) is weird and will get its very own blog, but suffice it to say the vaccine doesn’t work very well, and it follows different rules anyway.

The influenza vaccine has two different versions: an intranasal one and an intramuscular one. The intranasal one is tough to get antibody levels on. Most of the antibodies hang out in the mucosa lining the nose and mouth so a blood test doesn’t work very well. However, in studies it does a great job preventing the flu for at least 6 months (and really more like 12). The intramuscular vaccine makes antibodies, we can measure them, and they seem to help make the flu less icky, but when compared to the intranasal, it’s no contest.  

Strangles also comes in an intranasal and intramuscular variety. This is another tough vaccine to sum up in a sentence. Tell you what, I’ll write a future blog about Strangles too, just for you guys.

So to answer your questions: When it comes to Eastern Encephalitis, West Nile Virus, and Tetanus, your horse definitely needs to be vaccinated every 6 months at a minimum. Rabies needs to happen at least yearly. The intranasal flu can happen every year. Strangles and Rhino are complicated. If you prefer, a blood test can be done for EEE, West Nile, and Rabies, but knowing what the results mean is tough.

Don’t want to worry about any of this? Leave it all to my crack staff of minions. They’ll take excellent care of your horse so you can worry about how that pesky outside rein works.

Now show this cat some love: scroll down a little further, just below that beautiful green virus, and hit that subscribe button.

Springhill Equine vaccines blog

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 SpringhillEquine.com, or follow us on Facebook!

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