Equine influenza is often referred to as “horse flu,” and it is one of the most infectious and highly contagious equine diseases in the world. The virus is caused by two types of influenza A related to flu found in other species.

Within the United States, horses that develop influenza are usually around two or three years of age. Many of them come from being on the racetrack since contact with other horses is how it spreads rapidly. However, the virus can also be susceptible to senior animals and cause bacterial infections.

The influenza virus is a respiratory disease that is very damaging. It attacks the horse’s respiratory tract quickly. Here are the signs and symptoms, ways to help prevent and treat your horses if they catch equine influenza.

Signs and Symptoms of Equine Influenza

Any infected animal can spread equine influenza by coughing, contaminated food vestibules, brushes, tack, or more. Horses that are asymptomatic can still carry the virus and spread it among other horses. Humans, although they cannot contract the virus, can still spread the virus between horses by contaminated clothing or hands.

 Horses that have influenza tend to exhibit the following signs and symptoms:

• Dry cough
• High body temperature
• Nasal discharge (runny nose or smelly, thick mucus)
• Swollen lymph nodes
• Anorexia or loss of appetite
• Muscle pain or stiffness
• Depression

Horses might also display labored breathing and a reluctance to move around. The disease can be mild or severe, depending on the horse’s immune system. Still, it is rarely fatal unless a horse is significantly immunocompromised, including very young or old equines.

In rare cases, affected horses can develop another bacterial infection due to the virus. These infections include pneumonia, bronchitis, and pleuropneumonia. These infections can cause more long-term, debilitating effects, especially in foals.

Prevention of Equine Influenza

The best way to prevent your horse from contracting the virus keeping him vaccinated. Any horse that could get it, like a racehorse or show horse, should be vaccinated many times throughout the year. Normally, in the Northeast, our horses are vaccinated spring and fall.

Horses in general, even those not being shown or racing, should still get it, just to be on the safe side. The vaccine is inexpensive and the most effective way of protecting your horse. Depending on where you live, your vet might recommend other vaccines that your horse should receive on a regular basis.

Minimize contact with unfamiliar horses. Nose-to-nose greetings can allow viruses to pass between horses and you can’t always tell by their appearance if a horse is ill.

Diagnosis and Treatment of Equine Influenza

There are several strains of influenza, which are all airborne, spreading from horse to horse. The signs of flu are similar to other respiratory viral infections, but they are all treated the same, so it is relatively easy to diagnose. Unfortunately, there is no treatment that kills equine influenza.

If, by chance, your horse does contract the virus, be sure to keep it far from other animals in a well-ventilated area. The ventilation is essential because there has been some evidence that dust found within stables affects recovery in horses. You should also provide it with plenty of rest to recover quickly. Rest and supportive care are the best tools. Resting enables any damaged tissues to heal.

Horses should rest one week for every day of fever, which helps to lessen the development of a secondary infection. Medications may be recommended with higher fevers and antibiotics if the fever lasts beyond a few days or if a secondary infection has been detected.

Can Equine Influenza Affect Other Animals?

The biggest problem with influenza is that it doesn’t just affect horses and, because it is so contagious, it can be fatal to other animals. Donkeys, mules, and zebras are the most susceptible animals to influenza since it can be very severe for them. However, various strains of the virus can infect many other farm animals such as pigs, ferrets, birds, dogs, and cats.

The professional breeders from Mawoo Pets state that specific breeds of dogs who come in close contact with horses can develop respiratory disease. These breeds include greyhounds, rottweilers, dalmatians, border collies, and german shepherds. Most dogs don’t get all the virus symptoms but will exhibit some, including loss of appetite, cough, and lethargy.

Contact does not always lead to dogs contracting a respiratory illness, but taking precautions with horses is necessary so that the disease doesn’t spread to other animals that come in contact. Anything that comes into contact with a horse that could have been affected should be carefully and thoroughly cleaned and disinfected.

Final Thoughts

If your horses have jobs that bring them into contact with other horses, you can help reduce the chance of infection. Keep to a regular vaccination schedule as recommended by your vet. Take your horses’ temperatures frequently so that you know what “normal” is for them. It will enable you to detect early signs of any infection or viruses so that you can take appropriate measures right away to treat the symptoms and ensure that the flu does not spread.

The flu can survive for a couple of days but can be killed quickly and easily with proper cleaning using a diluted bleach solution. don’t let your horse drink from communal water troughs or buckets. Always bring your own buckets. Influenza virus can survive in water for several days.

If you have a new horse arrival on your farm or in your barn, you should quarantine the new equines for at least two weeks, which is long enough to observe whether the newcomer is developing any illness. Also, take the necessary measures to disinfect any areas that come in contact with these new horses while you are waiting to ensure they are healthy.

Periodically, I invite other bloggers to publish an article on Equine Ink. This article is written by Melissa Waltz, who grew up on a family farm with 4 dogs, sheep, a few hens, gooses, and two Appaloosas (named Ronny & Barty), and one American Miniature Horses (Moosa). Before opting for a full-time vet-tech career, she interned at Fort Worth Botanical Gardens in Fort Worth, Texas, and has first-hand experience working with farm animals including horses and managing the animal relations within the farm.