Updated 5 p.m. Aug. 15: The Large Animal Clinic at the UC Davis Veterinary Medical Teaching Hospital has resumed receiving horse patients as of today. Client-owned horses previously identified as having equine influenza have been treated in isolation, cleared of the viral disease and returned to their owners. Our original advisory, dated Aug. 5, is below.

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The Large Animal Clinic at the UC Davis Veterinary Medical Teaching Hospital is dealing with equine influenza, or horse flu, which was diagnosed Aug. 1 in a horse admitted to the hospital for an unrelated elective surgery.

Since then, every horse in the clinic’s barns has been tested daily. A few of the horses that had been kept in the vicinity of the first horse also tested positive for influenza, a respiratory viral disease much like influenza in humans. All of the flu-positive horses have been moved into an isolation unit separate from the main barns or sent home, providing they did not need further treatment and the owner chose to treat them at home. UC Davis veterinarians recommended that those horses being taken home be separated from other horses.

“We were very fortunate that the hospital’s routine surveillance screening and diagnostic program detected the initial case early so that appropriate measures could be implemented rapidly to limit the exposure of any additional horses,” said Pam Hullinger, a veterinarian and director of the Large Animal Clinic. She noted that horse owners are advised to make sure that their horses are current on their flu vaccinations as well as other vaccinations.

Equine influenza viruses, which do not infect people, dogs or other animals, are highly contagious among horses. Equine flu is often seasonal and more often affects the highly mobile, competition horse population and those in barns with high horse traffic.

The clinic is limiting its equine appointments to emergencies and critical recheck appointments until the veterinary staff has clear evidence that the equine part of the hospital is completely free of flu. All equine outpatient and emergency appointments are being handled by separate staff in an area away from the isolation barn.

More information on equine influenza and how it is being managed at the Large Animal Clinic is available online at: http://www.vetmed.ucdavis.edu/whatsnew/article.cfm?id=3597