Equine influenza is a highly contagious respiratory disease that affects horses, donkeys, and mules. It is caused by strains of the influenza A virus, most commonly H3N8. The virus spreads quickly through nose-to-nose contact, airborne droplets produced when infected animals cough or sneeze, and it can also be transmitted indirectly through contaminated equipment, clothing, or surfaces. Because horses often travel and commingle at events, the virus can move rapidly through groups of animals, making it one of the most significant respiratory diseases in the equine industry.
After exposure, horses typically develop signs within a few days. Symptoms often begin abruptly and may include a high fever, lethargy, loss of appetite, nasal discharge, and a deep, persistent cough. Although most healthy adult horses recover with rest and supportive care, the illness can be more serious in young foals, stressed animals, or those with weakened immune systems. Even in mild cases, the recovery period can be lengthy, affecting training schedules, competitions, and equine events. Because the virus spreads so readily and disrupts normal activities, prevention and early recognition are essential for minimizing impact.
See the following pages for more specific information about equine influenza:
- Equine Influenza Information for Animal Owners
- Equine Influenza Information for Veterinarians
Outbreak Information and Updates
For information on where Equine Influenza outbreaks have been reported or are currently occurring in the United States, visit the
Equine Disease Communication Center Equine Influenza page.
Equine Influenza Cases in Oregon
Resources
ODA Resources
Other Resources