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Home:Equine Diseases:Herpes

Equine Diseases - Herpes


Equine Herpes is also known as "The Cough" or "The Virus". Equine Herpes Virus is a highly infectious viral disease with 5 different strains but the two most common strains are EHV-1 and EHV-4.

EHV-1 (also known as Rhinopneumonitis) can cause respiratory diseases, abortions, neurological disease and paralysis

EHV-4 mainly causes respiratory disease but can also cause abortions.

Equine Herpes is spread via the respiratory tract and can survive for as long as up to 35 days in the environment.

Regardless of whether or not you notice symptoms of Equine Herpes in your horse, you should speak to your vet about vaccination and booster programmes against the Equine Herpes virus. This can be done at the same time as influenza and tetanus vaccinations. Vaccination is generally recommended for broodmares and most benefit is obtained if your horse is vaccinated before any perceived risk of infection. None of the current vaccines claim protection against the neurological form of EHV infection. Pregnant mares should be vaccinated in the 5th, 7th and 9th month of pregnancy. This is very effective in preventing abortion.

Mares that abort due to EHV-1 usually do not incur any damage to the reproductive area. It would seem that the same mare rarely aborts due to EHV in 2 successive seasons. This would seem to indicate that natural infection provides immunity and some degree of protection from Equine Herpes.




  • High temperature anything above 39.4C (103F)
  • Watery nasal discharge
  • Respiratory disorders
  • Swollen glands
  • Coughing
  • Loss of appetite.
  • Depression and lethargy - horse standing dejected with head down.
  • Abortion storms (EHV-1) and sporadic abortions (EHV-4) in some instances.
  • Paralysis
  • Loss of tail tone
  • Loss of bladder control
  • Difficulty urinating
  • Dehydration


Equine Herpes is highly contagious and is caused by any of the following:

  • Infectious droplets from other horses either from coughing or snorting
  • Infection from aborted foetuses
  • Infection caused by poor hygiene such as lack of hand washing
  • Infection caused by sharing equipment which has come into contact with infected horses
  • Infection spread by people who have touched or otherwise come in contact with infected horses and who have not changed their clothes


A horse showing any of the signs of Equine herpes should be isolated and a vet called immediately. A blood test is available to see if a horse has recently been exposed to the virus as well as several other tests which your vet may consider necessary to confirm a diagnosis.

Treatment will be prescribed such as

•  Anti-inflammatory medication ( banamine, DMSO, steroids)

•  Anti-biotics

•  IV fluid therapy if the horse is dehydrated

•  Cautherisation several times daily if difficulty urinating

•  Medication to support bladder function

•  Vaccination to work against both strains of the virus

•  Use of a sling if horse has trouble rising

Following on from any of the above treatment, the infected horse should be isolated immediately and avoid any contact whatsoever with other horses.

Try to limit one person only to treating and caring for the infected horse

Maintain good stable management ensuring the horse's stall is safe and well-bedded

If you have other horses, keep a careful watch for the spread of infection.

Strict attention to hygiene including proper hand washing is imperative.

Thorough cleaning and disinfection of facilities and equipment are needed to fight the Equine Herpes virus. Disinfectant manufacturing firms should be researched for thorough knowledge regarding the ability of their disinfectants to combat EHV.

Make sure you remove all organic debris like manure and nasal secretions before disinfecting.

The general prognosis for recovery is good with improvement seen within a few days of treatment, but sometimes a period of several weeks to more than a year may be required before horses with severe deficits show complete recovery whilst 4 6 weeks of rest should be allowed after recovery from the respiratory form of the disease.