Equine influenza, or the "horse flu," is a highly contagious upper respiratory disease that can cause serious secondary infections, especially in foals. Today, our Stillwater vets discuss what symptoms to watch for and how to treat a horse with influenza. 

What is equine influenza?

Equine influenza is one of the most common illnesses seen by horse veterinarians in the United States. It is an airborne disease that is spread mainly through horse coughing. An infected horse can spread the germs to horses that are up to 160 feet away. This means that horses that frequently attend shows, racetracks, or busy stables, are more susceptible to the disease. 

Equine influenza targets a horse's respiratory system, causing damage to the lining and mucous membranes in the animal's respiratory tract. The incubation period is typically 1-3 days after infection. 

Symptoms of Equine Influenza

Equine influenza affects the upper respiratory systems of horses, causing symptoms that are similar to humans experiencing influenza:

  • Deep, dry cough 
  • Nasal discharge 
  • Lethargy
  • Enlarged lymph nodes  
  • Lack of aphorseite 


Treatment for equine influenza involves treating the symptoms and allowing your horse to rest. Just like the human flu virus, there is no cure for equine influenza. At least 6 weeks of rest are recommended for the damaged liner of the upper respiratory tract to adequately heal. 

While your horse is healing it should be stabled in a clean, well-ventilated to avoid excess dust, which may exasperate its condition further. They should also be supplied with plenty of fresh hay and water. 

Sometimes horses can develop secondary infections, such as pneumonia, from equine influenza that may require antibiotics to treat. If your horse does not appear to be recovering you should contact your veterinarian. 


Prevention is the best method of defense against equine influenza. If your horse frequents shows, race tracks, or shared stables, you may want to speak to your vet about having your horse vaccinated against equine influenza. You can also take protective measures such as ensuring all the equipment you're using for your horse is sanitized, and that anyone coming in contact with your horse that has been around other horses practices good personal hygiene. 

If you are introducing a new horse to other horses on your property you should isolate them for 28 days to prevent the new horse from potentially spreading illnesses like equine influenza to your other horses. 

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding horses. For an accurate diagnosis of your horse's condition, please make an appointment with your vet.

Is your horse displaying signs of a respiratory tract infection? Our equine vets will come to you! Contact our equine vets in Stillwater today to make an appointment.