Equine Herpesvirus, or EHV for short, is found all over the world and has 9 different variations. The EHV-1, EHV-3 and EHV-4 variants are the most serious for horses. The EHV-1 and EHV-4 can cause flu like symptoms and respiratory diseases in horses along with neurological issues and miscarriages in pregnant mares. EHV-3 can cause coital exanthema, where lesions grow on or near the horse's genitals. For the past few years there has been an uptake in EHV-1 neurologic cases, also called Equine Herpes Myeloencephalopathy (EHM).
Sadly, EHM is exactly what my mare caught and it was a horrible experience. I want to share with you her story, her treatment and general medical knowledge of this devastating virus. If your horse or another is dealing with this, I want you to know I understand your fear, anxiety, sadness and hopelessness. I hope my mare's story will give you some hope and you learn more about this virus.
Before diving into her illness, I just wanted to give you some info about her and where I was during this awful period.
Olivia is a paint quarter horse mare who has had one foal, Golan, who is my other mare! She has had Potomac fever and other small issues here and there. When she got sick with EHV-1 she was about 17 years old and in Connecticut with my mom. I was in Michigan finishing up graduate school and Golan, her baby, was with me there.
Olivia got sick right in the beginning of 2021 when Covid was still an issue. I could not come home for fear of getting my family sick and I was healing myself from some stomach issues. I was a wreck listening everyday through the phone as the vet checked Olivia and tried walking her down the aisle to see how she was balancing. I was crying everyday and my partner had to come to the barn in Michigan to help me take care of Golan because I just was devastated. I was accepting that she was going to die and that I was not going to be there to say goodbye. But something deep down inside of me kept saying that it was not her time. And I am so thankful that voice was right!
Please keep some hope in you if this is happening to your horse. Our horses are so strong and our vets are getting better and better at handling this virus.
*Throughout this post you will not see any pictures of Olivia during treatment. It was a horrid experience that we most certainly did not want to document. If you want to see pictures of a horse sick with EHV-1, EHV-3 or EHV-4 you can find them on Google.
Transmission: How My Mare Got It
EHV is a common virus found in horses all around the world with many being infected and not getting sick at all. Research is still being done to understand how the virus mutates into the EHV-1, EHV-3 and EHV-4 strains.
The EHV-3 strain is transmitted through intercourse or contaminated breeding tools.
EVH-1 and EHV-4 strains are spread through respiratory secretions, contact with infected horses and contaminated equipment (think your pitchforks, grooming supplies, your shoes, feed/water buckets, tack, trailers,etc.). So these strains are unbelievably easy to transmit from one horse to another!
We are not a hundred percent sure how my mare got EHV-1, but a few days prior a horse had left the property for a clinic. When he came back he was put right next to my mare's paddock and they were able to touch nose to nose. Possibly he had gotten a strain that mutated when my mare received it. Not sure but that was the only thing that was different before she got sick.
Symptoms & Diagnosis
EHV-3 you will see red bumps and discharge around the genital region.
For EHV-1 and EHV-4, there can be many different symptoms including:
loss of tail tone
weakness in hind limbs
leaning against walls or rails for balance
down and cannot rise
Some horse may not have symptoms at all. It can be a very tricky disease. To diagnose a horse, your vet will take a nasal swab and do bloodwork.
If a horse is positive for EHV-1, your vet will report it to the state in which the whole barn will be in quarantine for 21-28 days.
When my mare first started getting sick, the barn owner noticed her eye twitching at night. By the morning she was uncoordinated and could not balance. She got a fever, her head tilted to one side, she could not eat, and could not control her urination. The vet took a nasal swab which showed a very high load of EHV. He also did bloodwork which showed she was fighting an infection. The barn was reported to the state of Connecticut and it was in quarantine for 21 days, and thankfully in that time no other horse showed symptoms or tested positive besides my mare.
For EHV-3 your vet may prescribe some antibiotics to make sure no other infections occur in the lesions but otherwise your horse should heal in a few weeks.
For EHV-1 and EHV-4 treatment is more intense. The horse will need to be immediately isolated to make sure not other horse become infected. You should keep everything you use for the infected horse sperate from the rest of the barn. Treatment for both strains focuses heavily on supportive care since there are not many anti-virials that work well for this virus.
The vet may administer fluids to keep your horse hydrated and and anti-inflammatory to bring down the fever and any swelling that may occur along the spine. In very severe cases your vet may recommend getting your horse up to a veterinary hospital for intensive care because if the horse goes down, the chance of death is extremely high. At the veterinary hospitals they have swings to help your horse stay upright.
For my mare we were giving her fluids, anti-inflammatories and pumped her with steroids to get the inflation down in her spinal cord so she could balance better. For days my mom and the barn were watching her and supporting her. The vet came every day for a good two weeks. Luckily she did not go down at all! Small improvements occurred every day and she fought so hard!
It took a good month for her to be able to walk more balanced. Her head tilt went away and slowly over a few months she was able to control her urination better. She did chip a tooth during that time and because of the spine being attacked, the vet told us no hard treats and soaked food due to us not knowing how well she can truly chew anymore.
The best way to lower your chances of your horse getting EHV-1, EHV-3 and EHV-4 is to get your horse vaccinated for EHV. However the vaccine does not protect your horse from getting the neurological form but it can help your horse fight it off better. This is one reason the vets believe she recovered. We keep her up to date on all her shots for both spring and fall.
Another very important prevention method, which too many barns are lax about, is quarantining new horses or horses who have left the property for events! It should be for a period of 21 days but 30 is strongly recommended!
Pregnant mares and mares with foals should be not be introduced to new horses during this vital time period. Keep them with their same herd mates or separate from other horses.
Many times after a horse has recovered from a neurological illness they will not be able to be ridden. But they can still do liberty and ground work. Just let them tell you what they are able to handle each day. Some days they may be feeling tired or not into doing much.
It has been a year and a half since Olivia has recovered. She has gotten her balance back fully and is out in a herd with Golan and two other mares she knew before. We have retired her mostly and do some liberty and groundwork here and there. But we did get a little surprise just a couple of weeks ago!!
Olivia can be do light rides here and there! I never ever thought she would be able to do this again!
But the vet came out for fall shots and did a general check up of her. He turned to my mom and I and asked if we had ridden her, and we answered of course not. And he said right on back, "You can!"
My mom and I were in shock! It was a miracle she survived and it is a miracle she can be ridden!
So just last week I got back on her for the first time in over 3 years! It was weird, exciting, wonderful and amazing!
We look forward to more amazing moments with her!
Thank you so much for reading about Olivia's illness and all about EHV. Below are veterinary sources I got my information from and that you can check out too.
If you need support with something like this please do reach out to me.
Keep the hope up!
Equine herpesvirus (EHV). USDA APHIS | Equine Herpesvirus (EHV). (n.d.). Retrieved October 29, 2022, from https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/equine/ehv/equine-herpesvirus
Peter, D. (2022, October 18). Equine coital exanthema - reproductive system. Merck Veterinary Manual. Retrieved October 29, 2022, from https://www.merckvetmanual.com/reproductive-system/equine-coital-exanthema/equine-coital-exanthema
Pusterla, N. (2020). FAQ: Equine Herpesvirus (EHV). AAEP. Retrieved October 29, 2022, from https://aaep.org/horsehealth/faq-equine-herpesvirus-ehv