What is EHV-1?

EHV-1 is equine herpesvirus 1, also known as rhinopneumonitis, a subset of herpes virus in horses.

This contagious virus can cause ongoing health problems for horses, including neurological disease, respiratory disease, newborn death, and abortion. It can be transmitted by direct contact between horses, air droplets, or nasal discharge from infected horses, and contact with items contaminated with the virus such as tack and grooming tools, buckets and mangers, or stable or stall surfaces. In addition, humans can transmit the virus from one horse to another on their skin, clothing, or footwear. This virus can live for weeks on surfaces, so great care must be taken around infected horses to keep it contained. 

Read More: EHV-1 Health Guide

EHV-1 is a contagious virus that can be transmitted by direct contact between horses, air droplets, or nasal discharge. Photo by Rita Kochmarjova/stock.adobe.com

Neurological Symptoms

Horses with EHV-1 that exhibit neurological symptoms are considered equine herpesvirus myeloencephalopathy (EHM) positive, which puts nearby horses at greater risk. EHM-positive horses will show incoordination of limbs and weakness in the hind end, and is usually fatal. A horse that lives through it will most likely experience ongoing neurological issues.

Symptoms of EHV-1 include: 

  • Fever
  • Respiratory disease
  • Cough
  • Nasal discharge
  • Abortion in pregnant mares
  • Incoordination and inability to balance

Photo 1 by Pelana/stock.adobe.com; photo 3 by Jack F/stock.adobe.com

What You Can Do

1. Signs of illness usually appear 4 to 6 days after exposure to EHV-1 but can appear within 24 hours. If you see symptoms of EHV-1 or know your horse has been in contact with an infected horse or facility, have your veterinarian take a nasal swab or blood sample to test for it. 

2. For horses with EHV-1, a veterinarian may prescribe anti-inflammatory drugs; for horses with EHM, antiviral medications. 

3. Prevention is key. if your horse shows signs of illness, keep him home and away from other horses. If he tests positive, isolate him from all other horses and take all biosecurity precautions when caring for him to keep the virus from spreading. If you’re away from home or traveling with your horse when encountering EHV-1, do not enter
or depart a facility until cleared by a veterinarian. 

4. You may administer a vaccine to protect against respiratory and abortion manifestations of EHV-1, but current vaccines don’t prevent EHM. Some horse shows, events, and boarding facilities will require vaccination before allowing your horse to take part or be stabled on site. 

Read More: Equine Flu Fight

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