On Oct. 20, 2015, the Veterinary Teaching Hospital at Oregon State University notified the public that it will not accept horses for anything but emergency services until at least Monday, Oct. 26, due to a diagnosed case of equine influenza virus at the hospital.
One horse has been tested and found to be infected with this virus, and it has been moved to an animal isolation facility for treatment. Other horses at the hospital are being monitored for any signs of infection, and if one or more are found to be infected, it could further delay the opening of the facility, officials say.
Equine influenza is a highly contagious respiratory disease in horses that typically is not fatal, but is a particular concern to foals and pregnant mares. Other than equine species, the situation will not affect the care of any other small or large animals at the hospital.
Officials wish to emphasize that this is equine influenza virus, not equine herpesvirus-1, a far more serious disease that is often confused with the influenza virus.
Equine influenza is endemic in the United States, and outbreak situations occur intermittently. It’s not transferable to humans or other animal species, but it can spread rapidly among horses and other equine species. It is the most common contagious respiratory pathogen of horses, and most infected horses show mild clinical signs from which they fully recover. However, young, elderly or pregnant animals are more vulnerable to viral diseases such as equine influenza, which can cause abortion in pregnant mares.
“We acted quickly to diagnose and isolate the horse that was showing signs of the disease, and hopefully no more animals will be found to be infected,” said John Schlipf, DVM, MS, DACVIM, a large animal internal medicine specialist in the OSU College of Veterinary Medicine. “We will be able to accept emergency cases if needed.”
The first clinical sign of influenza in horses is typically a fever, followed by cough, nasal discharge and lethargy. Horses with a rectal temperature of greater than 102.5 degrees, cough or nasal discharge should be evaluated by a veterinarian.
Infected horses can “shed” or transmit the virus for up to 10 days after incubation, although the peak of shedding occurs three to five days after infection. Horses that show signs of the disease should be isolated from other horses for 10 days after clinical signs first appear. Testing of nasal swab samples can be used to identify influenza infection in horses and to determine when horses infected with the virus are no longer a risk to others.
The influenza virus is easily killed by a variety of disinfectants, and thorough cleaning of stalls and equipment can help prevent the virus from spreading. Vaccination of horses during an outbreak in a training facility or barn can be beneficial and should be performed in consultation with a veterinarian, since it may have implications for influenza test results.
Anyone with concerns about their animals may contact their veterinarian or the Lois Bates Acheson Veterinary Teaching Hospital at OSU, at 541-737-2858 or http://vetmed.oregonstate.edu