By Mark Floyd
OSU Extension Service
CORVALLIS, Ore. – A horse from Eastern Oregon that was referred to Oregon State University’s veterinary teaching hospital because of illness has been diagnosed with equine influenza virus, a highly contagious respiratory disease in horses that typically is not fatal.
The four-year-old quarter horse mare, which recently arrived in Oregon from Texas, has been placed in isolation and is being treated.
OSU veterinary clinicians say equine influenza is not transferable to humans or other animal species, but can spread rapidly among horses and other equines. It is the most common contagious respiratory pathogen for horses and most animals fully recover. However, young, elderly or pregnant animals are more at-risk for viral diseases such as equine influenza.
“Equine influenza is especially dangerous to foals and the foaling season just started,” said Keith Poulsen, an internal medicine specialist at the Lois Bate Acheson Veterinary Hospital in OSU’s College of Veterinary Medicine. “The virus can be spread by direct contact with nasal discharge, or when aerosolized from coughing.”
The Large Animal Internal Medicine and Surgery Services program at OSU’s College of Veterinary Medicine is working with the state veterinarian’s office to inform veterinarians and horse owners about the disease.
Poulsen said the first clinical sign in horses is typically a fever, followed by cough, nasal discharge and lethargy. Horses with a fever of greater than 102.5 degrees should be seen by a veterinarian. Horse owners should also consult with their veterinarian about vaccinations, he added.
Infected horses can “shed” or transmit the virus for up to 10 days after incubation. Horses that show signs of the disease should be isolated from other horses for 10 days after clinical signs first appear.
“The good news is that many disinfectants can easily kill the equine influenza virus, and thoroughly cleaning stalls and equipment can help prevent the virus from spreading,” Poulsen said.
The Eastern Oregon horse was purchased at a sale in Hermiston last weekend and several horses that were in close contact with it also have developed signs of illness, though they have not yet been diagnosed with equine influenza virus, officials say.
The horse will remain at OSU in isolation until it fully recovers. As an added precaution, the OSU hospital is only accepting equine patients requiring emergency treatment until Wednesday, Feb. 27. Horses being referred for elective surgery, lameness or non-emergency conditions will be delayed until after Wednesday.
“The college has some of the most sophisticated isolation facilities of any facility in the country,” noted Helio de Morais, interim director of the Lois Bates Acheson Veterinary Hospital. “Safely treating animals such as these – and working with veterinarians and animal owners around the state to prevent the spread of these diseases – is what we do best.”