How I Navigated EHV-1 in My Boarding Barn
Each spring, we give all our horses their annual inoculations, which include the vaccine for rhinopneumonitis (aka, EHV-1). This carries us through our area’s limited show season that ends with our county fair at the beginning of August. Other than two of my boarders who go to a couple of local casual “fun” hunter paces, none of the clients in my barn have traveled anywhere with their horses to horse events.
On Feb. 6, one of my lesson horses, Star, who is 32 years old, wasn’t eating her feed and had a temperature of 102.3ºF, so I contacted our local veterinarian, Hannah Smith, DVM, of Southport Veterinary Services, in Pine City, and she examined Star, who wasn’t coughing and didn’t have evidence of nasal discharge. Dr. Smith took a nasal flush and blood samples, and we treated Star with IV fluids and antibiotics. Through the next four days, we kept a very close eye on the old horse, suspecting things like organ failure or cancer as the cause of her illness, but she started to rebound, and began eating again. By Feb. 10, she was eating all her ration and her temperature was staying in the 99º range, so we thought we were out of the woods.
However, on Feb 11, Dr. Smith called me with the news that Star had tested positive for EHV-1. I felt like I had been kicked in the gut. What? How could this be? No horses had come or gone from my barn for months. What was going on?
I went public about my situation immediately upon learning about the positive results. That very night, I contacted one of the local stables (because I was aware of our clients riding at each other’s facility) to let them know about the case. We took the temperatures of all the horses in my stable that night, even though none of them showed any outward signs of illness. Fortunately, every horse had a normal temperature.
On Feb. 12, I purchased and put into place a significant array of hand and boot disinfecting materials and instituted complete biosecurity measures that were approved by the state veterinarian.
On Feb. 13, I held an informational meeting at my stable for my clients, with a representative veterinarian from the New York State Department of Agriculture and Markets. Dr. Arthur Sherman (field veterinarian, Division of Animal Industry, NYS Department of Agriculture & Markets) came to the meeting, and we had a very informative discussion about EHV-1. More than a dozen of my clients attended the meeting. Dr. Sherman’s information and related experiences put everyone at ease, for sure, as he answered all our questions. Dr. Smith also provided many references and websites, and I forwarded these to my clients.
During the meeting, Dr. Sherman referred to the very informative “IDOHC EHM Incident Guidance Document,” which explains the versions of the EHV, including the neurologic form (referred to as equine herpesvirus myeloencephalopathy, or EHM).
My old horse, Star was classified as a “confirmed EHV-1 case,” defined as (from the IDOHC EHM Incident Guidance Document):
“A suspect EHV-1 case that shows no neurologic signs but has laboratory evidence of Equine Herpesvirus-1 by virus isolation and /or PCR testing of nasopharyngeal/ nasal swab or blood (buffy coat) specimens along with clinical signs consistent with EHV-1 infection, such as fever, limb edema, abortion or nasal discharge”.
And also from the same document:
“Virus isolation is considered the gold standard for confirmatory laboratory diagnosis of EHV-1 infection, although the time required to obtain a positive result limits its value for outbreak management.”
So, the PCR test, which detects viral DNA, at Cornell University’s diagnostics laboratory indicated that Star’s virus was the respiratory (non-neurologic) kind.
The challenge at this point was that Star was already clinically normal by the time we obtained the test results. Fortunately, when Star first became sick, I had already warned all my clients (I send out daily email updates) and advised them that something was going on and to not touch Star and to practice “extra good hygiene” in the barn.
We will continue to monitor our horses’ temperatures, and when we can produce a report of 14 consecutive days of no horses with “fever temperatures related to the EHV-1 or EHM viruses,” (temperatures taken twice per day), it is our hope that our quarantine will be lifted.
So, how did the virus get into my stable? How did Star get sick? We absolutely don’t know. Here is what I learned from all of this:
1. If horses on your farm rarely leave your property, you may still be at risk for your horses getting sick with a virus. None of the horses on my farm have traveled anywhere since Oct. 25, 2015.
Old Star hasn’t been anywhere in years–she’s been on the farm teaching beginner riders. This mare was happy, in good shape, and was not stressed in any way (stress being a risk factor for EHV-1 infection manifesting). She was used for about three to four lessons per week. Hardly stressed.
2. You might also think you’re safe if you don’t have any visiting horses to your farm. I have had no visiting horses in my stable since October 2015. We held an in-house schooling show on Oct. 31, and only one outside horse came to the show, a mare from a private home stable, and she rode in one dressage class and went home. She had no contact with any of my horses.
3. This virus can remain in a horse’s body, latent (not causing signs), forever, and can pop up and make the horse sick again, if the horse becomes “stressed,” such as being transported or shown at a competition.
Old Star surely hasn’t been stressed. She’s been eating well and used lightly in the lesson program and seems to generally be very content. It is possible that a latent virus erupted, but we can’t know for sure.
4. People need to know that the virus can be carried around on “fomites.” These include human hands and clothing, boots, brushes, tack … almost anything (Horses can even serve as fomites, carrying the virus around on their skin/hair coat!).
I have now become acutely aware that any human traffic coming and going to my stable has the ability to bring in a disease to my horses, and I have taken measures and instituted protocol to prevent this from happening again. Hand disinfection stations and foot disinfection pads are in place and will remain a part of a permanent “biosecurity” protocol at my stable.
Many stables owners and managers might hide EHV infection in their barns. Instead, I went public and posted information about my experience on Facebook and shared via email. As the owner of another stable told me, by going public with education, perhaps I can help save the life of another person’s horse.
The take-away message is, if it could happen to me, then it could happen to you. If it does, set up your disinfection stations at the entrances of your stables. Get everyone to wash their hands. Educate your clients of the importance of “between barns” hygiene. Talk with your veterinarian to establish a year-around protocol for inoculating horses for the EHV-1 virus, as well as other diseases. You can’t assume that if your horses don’t have contact with other horses, that you’re safe from disease.
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