CORVALLIS, Ore. - The Lois Bates Acheson Veterinary Teaching Hospital at Oregon State University will resume normal operations on Thursday, Dec. 4, following several cases of equine influenza that for the past week had kept it from accepting horses for anything but emergency services.

There are three remaining horses that still have the infection but are being housed in an isolation unit. They pose no risk to the general hospital operation, officials say, where no horses are now testing positive for the virus.

Equine influenza is a highly contagious respiratory disease in horses that usually isn't fatal, but is a particular concern to foals and pregnant horses, since it can cause abortion. The original source of the infection appears to be a horse admitted to the hospital.

All horse stalls in the Large Animal Hospital have been disinfected and left empty for an adequate time to kill any remaining flu virus in a dry environment.

"We'd like to thank all of our clients for their patience and cooperation," said Ron Mandsager, interim associate director of the hospital. "Equine influenza is endemic in the U.S. and sometimes these situations occur, and we had to take the necessary precautions to protect the health of our animals."

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.

Incidents such as this, hospital officials said, should remind all horse owners to vaccinate their animals, practice good biosecurity, and monitor horses closely when they are in contact with other horses during and after events like fairs, competitions and trail rides.

The first clinical sign of this disease 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.

Anyone who has concerns about the health of their animals should contact their veterinarian or the Lois Bates Acheson Veterinary Teaching Hospital at OSU, at 541-737-2858 or

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Ron E. Mandsager, 541-737-6440