MADISON – A new outbreak of an often fatal disease in horses has prompted State Veterinarian Dr. Robert Ehlenfeldt to warn horse owners of the need for good biosecurity, and that includes always isolating horses when they return from shows or competitions.
Horses from at least 29 states, including two in Wisconsin, may have been exposed to equine herpes virus-1 or EHV-1, at a recent Utah competition. There is no human health threat.
“Any time you bring horses back from a situation where they’ve been exposed to other horses, you have to assume they may also have been exposed to disease,” Ehlenfeldt says. “Do yourself a favor and isolate them, so you’re not risking your other animals. The same is true for any species you take to shows.
“If a horse gets infected with EHV-1, there’s nothing anyone can do except try to make the horse more comfortable. The infection may run its course, or it may kill the animal. There’s no treatment, and no vaccine for the worst strain that attacks the central nervous system. That’s why prevention is so important, and you need good biosecurity to prevent disease.”
An online listing shows nearly 100 horse shows in Wisconsin between now and October, in addition to fairs and trail rides where horses from different farms may be mingled. Owners who take their horses to such events need to beware, the State Veterinarian says.
The outbreak came to light when two horses in Colorado became ill after returning from the National Cutting Horse Association’s Western National Championships in Ogden, Utah, April 29 through May 8. A horse in Washington has also tested positive after returning from the same show. That horse was a patient at the veterinary hospital at Washington State University, restricting access to the hospital for other horses. In all, horses from 29 states and Canada competed in Utah and may have been exposed.
Ehlenfeldt recommended these biosecurity precautions to prevent introducing disease:
• Isolate for seven days new horses and those returning from shows or anyplace where they’ve mingled with other horses. If they were exposed to confirmed EHV-1 infections, isolate them at least 21 days after returning.
• Encourage barn personnel and riders to wear leather or rubber footwear that can be disinfected, and keep a disinfectant tub with a 1:10 bleach-water solution at the barn entrance. Ask all visitors, including blacksmiths and veterinarians, to step in the disinfectant wash before entering the barn, and change the solution daily.
• Wash hands before handling horses.
• Don’t share water buckets, feed tubs or stalls among horses.
• Segregate horses into the smallest possible groups to limit the number of animals exposed if one is infected.
• Take rectal temperatures daily. Isolate any horse that has a temperature over 101 degrees F. or any other sign of illness, and call a veterinarian.
EHV-1 is one of nine equine herpes viruses, and one of the three most serious. It may affect the respiratory, reproductive, or central nervous system.
EHV-1 spreads when horses in close contact cough or sneeze, and on contaminated hands, water and feed. It can cause abortion in pregnant mares and death in foals. The neurologic strain may cause horses to be uncoordinated and unable to stand and to produce urine and manure. They may also have swollen, inflamed legs and hemorrhages on their gums.
