How Does a Horse Get Equine Herpes Virus (EHV-1)

First, it’s important to understand what EHV-1 is. Like human influenza (the flu), there are multiple strains of the equine herpes virus. EHV-1 and EHV-4 are the most common strains that are spread to equines in almost every country, including the United States. It’s an upper respiratory tract infection that may not cause serious side effects in most horses. However, there is a chance that your horse could have a more critical response to the pathogen.

How Is EHV Transmitted?

Equine Herpes Virus (EHV-1) is often called Viral Rhinopneumonitis, or “Rhino” for short. It is contagious and can be spread by horses that aren’t even showing symptoms. Your horse can become infected by direct contact (nose to nose touching), indirect contact (from a contaminated bucket) or by breathing droplets in the air from a sick horse. Keep in mind, you can spread the virus from horse to horse with your hands, equipment or clothing.

Signs and Symptoms of Rhinovirus

Horses will have typical upper respiratory infection symptoms such as a runny nose, a fever and/or cough. The lymph nodes under the jaw may swell. They’ll feel under the weather, lethargic and probably have no appetite. For most, this is as serious as it will get. However, be advised, it can cause abortion in pregnant mares.

For some, the virus becomes serious. Equine herpesvirus myeloencephalopathy (EHM) is another name for the neurologic disease associated with equine herpesvirus (EHV) infections that causes critical and often fatal symptoms. You’ll know the virus has turned severe (neurological) if your horse shows any of the following signs:

  • Uncoordinated
  • Weak hind end
  • Lethargic
  • Leaks urine
  • Poor tail tone
  • Can’t get up from ground
  • Holds head at a tilt
  • Can’t maintain balance without leaning on fence or wall

How Can I Protect My Horse From Getting It?

Horse shows and equestrian communities around the world, including Ocala, Florida and Europe, are asking owners, exhibitors and anyone in direct contact with horses to take extra precautions to stop or slow the spread of this virus.

  • Quarantine new horses
  • Don’t share tack or grooming items
  • Don’t use shared water troughs, buckets or scoops
  • Wash your hands often
  • Don’t allow people to pet or feed your horse
  • Keep your horses vaccines up-to-date
  • Disinfect horse show stables before use
  • Disinfect horse trailers
  • Only ship with transporters that clean and disinfect between loads of horses

My Horse Had EHV-1 and Didn’t Have Serious Symptoms

Many horses have contracted and tested positive for EHV-1 during their lifetime. Thankfully, in most cases, the illness is not serious, causing only mild respiratory symptoms. Your horse may have only shown minimal signs of being sick such as nasal discharge, fever and cough.

Unfortunately, the outbreaks of rhino viruses around the world and in US states like Florida, Connecticut and California, are developing into EHM that causes dangerous, neurological symptoms. This has resulted in the death of horses around the globe.

Take Extra Precaution to Prevent the Spread of EHV and EHM

Maintain your EHV-1 and EHV-4 equine vaccines as well as those recommended by your veterinarian. Keep your horses healthy in order to fight illness or disease. Provide plenty of hay (fiber) to keep their digestive system functioning well. A healthy gut typically means a healthy immune system. Immediately quarantine any horse that shows signs of being ill especially if he or she has upper respiratory symptoms. Contact your equine vet for diagnosis, testing and treatment.

Treatment is usually supportive care. Try to encourage your horse to eat and drink. Offer fresh water and electrolytes to prevent dehydration. Your vet may recommend the use of medications to help reduce fever and respiratory tract inflammation. Medication to help your horse breathe better may also be prescribed. Allow the horse to rest and full recovery before returning to work.

FEI is maintaining a database for the current EHV-1/EHM outbreaks in the US and abroad. Get the latest information and statistics at