Take Steps to Keep Horses Healthy
K-State veterinarian says equine herpesvirus myeloencephalopathy occurrence is a reminder to take precautions.
It’s springtime. For many horse enthusiasts that means heading out to horse shows and rodeos. Two recent cases of equine herpesvirus myeloencephalopathy (EHM) discovered after a barrel-racing event in Nebraska should serve as a reminder that good biosecurity practices can help prevent illnesses, said a Kansas State University (K-State) veterinarian.
Beth Davis, a professor of clinical sciences in K-State’s College of Veterinary Medicine referred to two cases of EHM that were diagnosed after a large barrel-racing event in Lincoln, Neb., April 10-13. One of the horses, from a farm in northeast Kansas, became ill after its return to Kansas, according to the Kansas Department of Agriculture. It was euthanized and samples tested by the Kansas State Veterinary Diagnostic Laboratory. Equine Diagnostics Services in Lexington, Ky., confirmed EHM.
The other confirmed case was a horse from Wisconsin that also was present at the Nebraska event.
“EHM can be highly contagious,” said Davis of the neurologic disease associated with equine herpesvirus infections. “If we’re not careful, this virus can spread and can be life-threatening.”
The virus that causes EHM is called EHV-1. EHV-1 is common and can be present in a horse for years, causing minor illness when first contracted and, in most cases, it never develops into EHM. Most commonly EHV-1 causes mild to moderate respiratory disease, abortion in pregnant broodmares and/or illness in young foals.
Fortunately, only rarely does EHV-1 actually cause EHM. In some cases, and especially in times of stress, however, the virus can be reactivated and shed to others. Stressful situations such as strenuous exercise, long-distance transport or weaning can be the trigger for viral shedding.
“What determines whether a horse gets sick is its immune system,” Davis said. “If a horse’s immune system is not strong and the animal is under stress, EHV-1 can develop into EHM. We usually see this after horses have been in a large group, such as at horse shows, rodeos or racetracks.”
Signs and prevention
Symptoms usually start with a fever. The illness may progress and show signs of weakness and a lack of coordination. Urine dribbling and lethargy may also signal the disease, and sometimes the illness progresses to a horse going down, Davis said. In the worst cases, in which the animal can’t rise (also called recumbency), they can die or are so ill that they will be euthanized.
She provided tips and facts for horse owners.
- EHM is easily spread by direct horse-to-horse contact. It can also be spread by contact with contaminated objects, such as tack, grooming equipment, feed and water buckets, and people’s hands and clothing.
- Contact your veterinarian if your horse’s temperature is 101.5° F or higher. A normal, healthy temperature for a horse is 100° F.
- Currently, there are vaccines available to boost a horse’s immunity. They’re labeled to fight respiratory disease and abortion, but they’re not labeled for the prevention of EHM. Work with your veterinarian to select an ideal vaccine program.
- Some horses recover from EHM, but not without treatment. In some cases, even treated horses can die.
- People cannot get sick from EHV-1, which causes EHM, so there is no threat to humans. It is most commonly an equine disease, although it can occur in camelids, such as llamas and alpacas.
“Personally, I think if we were going to have a major outbreak, we probably would have seen more cases by now. We had two from the barrel-racing event, but we’re more than two weeks out from that, and no other cases have been reported at this point,” she said.
Davis said she and K-State veterinarian Laurie Beard are available to answer questions and concerns Kansas horse owners may have. They can be reached at 785-532-5700.
More information about EHM and EHV-1 and keeping horses healthy is also available at www.aphis.usda.gov/vs/nahss/equine/ehv/equine_herpesvirus_brochure_2009.pdf and www.agriculture.ks.gov/news-events/news-releases/2014/04/29/ehv-1-case-confirmed-in-kansas.
