On Feb. 21, an attending veterinarian confirmed one horse in Multnomah County, Oregon, positive for equine influenza, with nine additional suspected cases. The 9-year-old Thoroughbred gelding also tested positive for the respiratory form of equine herpesvirus-1 (EHV-1). He started experiencing clinical signs of coughing, fever, and nasal discharge the same day he tested positive. Reported as undervaccinated, the gelding is affected and alive. The affected and suspected horses are under voluntary quarantine.

About Equine Influenza

Equine influenza is a highly contagious respiratory disease that infects horses, ponies, and other equids, such as donkeys, mules, and zebras. The virus that causes it is spread via saliva and respiratory secretions from infected horses. Horses are commonly exposed via horse-to-horse contact; aerosol transmission from coughing and sneezing; and contact with human’s contaminated hands, shoes, or clothes or contaminated tack, buckets, or other equipment.

Clinical signs of equine influenza infection can include a high fever (up to 106°F); a dry, hacking cough; depression; weakness; anorexia; serous (watery) nasal discharge; and slightly enlarged lymph nodes. Consider monitoring your horse’s health at shows by taking his temperature daily, which can help you pick up on signs of infection early and take appropriate measures to reduce disease spread.

Vaccination is an important and inexpensive way to protect your horse. US Equestrian requires proof that horses have had an equine influenza vaccination within the six months prior to attending organization-sanctioned competitions or events. Your veterinarian can help you determine what other vaccines your horse might benefit from