EHV-1 case confirmed in northeast Kansas horse
By Kylene Scott
There are billions of dollars tied up in the horse industry, and keeping equines safe and healthy becomes a priority for owners. Thousands of dollars are spent on the horses themselves, tack and equipment, and everything that goes along with the care of the animals. Even more money is spent on costs associated with showing and competing. When a disease outbreak occurs, owners will work to protect their investment.
A horse in northeast Kansas has been confirmed positive with a wild type of a non-neurotropic case of Equine Herpes Virus, or EHV-1. The Kansas Department of Agriculture Animal Health Commissioner Dr. Bill Brown reported the confirmation April 29. EHV-1 is normally fatal.
According to the KDA, the affected horse was euthanized and samples were sent to Kansas State Veterinary Diagnostic Laboratory April 25. Preliminary tests showed lesions consistent to EHV-1. Additional samples were then sent to the Equine Diagnostics Services in Lexington, Kentucky. Results from a PCR test were received late April 29 confirming the positive nature of the samples. A Wisconsin horse has also been confirmed positive for EHV-1 and was euthanized days following a large barrel racing event in Lincoln, Nebraska, April 10 to 13. The Kansas horse was also at the Nebraska event.
What is EHV-1?
Valley Center, Kansas, veterinarian Quinley Koch said the EHV-1 is a large group of DNA viruses that can cause neurologic form, respiratory disease, abortion and neonatal death. When testing for EHV-1 the PCR assays differentiate the neuropathic EHV-1 from the non-neurotropic EHV-1 based on their DNA.
“The non-neurotrophic form has a different DNA than the neurotrophic form, but a percentage of the non-neurotrophic form can still cause neurologic signs and Equine Herpesvirus Myeloencephalopathy,” Koch said.
The incubation period is 4 to 21 days, according to Koch.
“By 2 years of age, almost all horses have been infected with EHV-1. The initial exposure generally occurs in foals from contact with their dams,” Koch said. “The virus can then become latent (inactive) in the horse’s body. This creates a carrier state that is lifelong.”
Horses of any age that are carriers of EHV-1 do not show external signs of the disease while the virus sits in the latent phase. The virus can be reactivated during times of stress such as hauling, performing, weaning and strenuous exercise.
KDA recommends owners monitor their animals carefully for signs of EHV-1. This includes checking temperatures twice a day for changes and implementing good biosecurity practices for equines. The virus is easily spread by airborne transmission, horse-to-horse contact and by contact with nasal secretions on equipment, tack, feed and other surfaces. Caregivers can spread the virus to other horses if their hands, clothing, shoes or vehicles are contaminated.
Koch agrees with the KDA recommendations and suggests horse owners should keep the horse at home, isolated from other horses and take the horse’s temperature twice daily.
“The EHV-1 virus generally causes a fever as the first sign, so when taking twice-daily temperatures, if the horse’s temperature is 101.5 F the owner should call their veterinarian immediately,” she said. “Often times after the horse spikes a fever, its condition will quickly degrade to ataxia, inability to urinate, dog-sitting and possible recumbency.”
Symptoms of the disease may include a fever, nasal discharge, wobbly gait, hind-end weakness and dribbling of urine. The neurological form, including wild strains, of the disease is often fatal.
Precautions to take
Koch said when facing an EHV-1 outbreak, owners should keep their horses at home and away from all other horses until the outbreak has passed.
“In general, ways that the virus is spread include tack and bits, grooming equipment, buckets, people’s hands or clothing,” she said. “The air around a horse that is shedding the virus can also be contaminated with infectious virus.”
Those horses who stay home and don’t travel are at low risk of being exposed, unless they are comingled with those horses that do travel. Koch said horses that travel but were not at the specific event are at risk if they are exposed to a horse that was exposed at the event and is possibly shedding the virus. Following strict biosecurity methods is the safest way to travel. She suggests the following tips from the Center for Equine Health-UC Davis and the American Association of Equine Practitioners website:
1. Keep your horse from touching other horses, especially nose-to-nose contact.
2. Take your own buckets and do not share buckets or allow your horses to drink from community water. People can also transmit the virus via their hands and clothes.
3. Do not share equipment, especially bits.
4. You can administer immunomodulators, such as Zylexis or Eqstim to help improve your horse’s immune system be better prepared when traveling and stressed. These products have a very specific time frame of administration and duration of activity. The entire series of three must be given before hauling and the duration of activity is 10 days after the last injection.
5. Vaccinate your horses for EHV. No vaccine is currently labeled to prevent Equine Herpesvirus Myeloencephalopathy, but it is still a good precaution to take for your horse. University and private researchers are looking into existing vaccines to determine whether they protect against EHM.
The facility that held the barrel race where the two horses attended, the Lancaster Events Center in Lincoln, Nebraska, issued a statement on April 29 on its website about biosecurity actions the center will be doing before events scheduled to start May 2.
“The Lancaster Event Center has decided to conduct before Friday (May 2) morning a thorough disinfection of all buildings where horses have been present in April (most of our buildings totaling over 300,000 square feet) including: Pavilions 1, 2, and 3; Amy’s Arena and the Multi-purpose Arena. We are using the highly recommended, natural, safe and effective disinfectant used in many horse facilities, called Nixall, you can find more information at www.nixall.com,”; the statement reads.
LEC will also be spraying group areas—aisles, arenas, walkways and doorways—as well as making stall disinfecting spray available to horse owners. The center made the disinfectant available to those who attended the barrel race in early April.
“We are now disinfecting every stall top to bottom (floor, walls, bars). We are exploring if we can get the heat on in the buildings with dirt floors to help get it nice and dry as well as it is true the virus can persist in dirt up to 35 days if in a cool and wet environment,” Amy Dickerson, managing director of LEC, said.
Upon arrival, horse owners will find that LEC is continuing to offer ready-to-spray Nixall in convenient spray bottles and cleaning kits (bucket, gloves, rags) for sale at a reasonable price, which can be delivered along with shavings. The center plans on disinfecting for as long as the outbreak remains reports say.
Dickerson wrote that three small horse events scheduled for April 29 and 30, which would have around 100 horses total, would have to postpone their events until after May 2 in order to do a thorough disinfecting. All future horse shows on the LEC schedule are still planned to be held starting May 2.
Due to the nature of this disease, the Kansas Department of Agriculture Division of Animal Health is not imposing any restrictions on equine events or movements at this time; however, horse owners are encouraged to take precautionary measures when traveling or participating in equine events. If horse owners are planning on participating in upcoming horse events across Kansas, call ahead to event planners to confirm whether the event is still taking place.
One association postponed its event in light of the positive EHV-1 horse, the Kansas National Barrel Horse Association State Finals, in Topeka.
“The Kansas NBHA wants to take a proactive role in trying to help control the EHV-1 virus to help protect our community of horses by choosing to reschedule our Kansas NBHA State Championships set for May 9 to 11,” Kansas NBHA State Director Dawn Dawson said.
Keeping horses at home and limiting exposure is one way to start controlling the spread of the disease.
“Stopping the movement of horses or large gatherings of horses is the first step in preventing the spread of the virus,” Dawson said. “The incubation periods and normal quarantine requirements will not expire until approximately the timeframe of our event and we feel this is the best decision for all to help control this highly-contagious disease.”
On the association’s website, Dawson further explained their actions.
“We are working with the Kansas Expocentre in finding a date where we can reschedule this event from their very limited options. We are currently looking at possible dates in August or October. We have a lot of conflict checking on big events to do. We are also working on a process to allow for carryover of the current entries, a refund request form for members needing that option, and an additional new entry deadline for members who might be able to enter the rescheduled show,” the website reads at www.ksnbha.com.
Dawson suggests horse owners visit their local veterinarian for ways to manage horses for EHV-1.
“Our thoughts and prayers to those individuals who are dealing with the tragic loss of a horse through this,” Dawson wrote. “Please be sure to monitor your horses carefully.”
Koch also suggests if owners have questions regarding EHV-1 to call either their veterinarian or a university such as Oklahoma State University (which does EHV research) or Kansas State University.
“It is very important that owners don’t believe everything they read on Facebook and other online forums,” she said. “When reading online, owners should read university sites, such as UC Davis or go the American Association of Equine Practitioners for information. These types of sites will have the most current and best information.”
A great resource for owners is the AAEP website for owners, www.aaep.org/info/owners.
Kylene Scott can be reached by phone at 620-227-1804 or by email at firstname.lastname@example.org.