Equine Viral Arteritis
Equine Viral Arteritis (EVA) is a venereal and respiratory disease which can affect horses, mules and donkeys. It is a notifiable disease in all stallions, and in mares that have been mated or inseminated within 14 days. The disease is common in warmblood horses on the continent. The disease does not affect humans.
If notifiable disease is suspected, contact DAERA on 0300 200 7840 or your local DAERA Direct Regional Office. Failure to do so is an offence
Vaccination
Routine vaccination against EVA is recommended for stallions and teasers. In the UK, routine vaccination of mares is not recommended. One vaccine, Equip Artervac (Zoetis), is available in the UK normally.
Horses must be blood tested before vaccination to show that the animal was seronegative prior to vaccination.
Further details of how to prevent EVA can be found in the HBLB Codes of Practice HBLB International Codes of Practice | Prevention
During 2023-24 production of the Artervac vaccine was temporarily suspended. Guidance on vaccination for horses where the vaccination had lapsed can be found at June 2025 EIDS Artervac Vaccine Update
Clinical signs
Signs of equine viral arteritis can include:
- abortions (failed pregnancies in mares)
- conjunctivitis (bloody tissue around the eye known as ‘pink eye’)
- swelling of scrotum and prepuce or udder, also around eyes and lower legs
- fever and runny nose
- depression
- lethargy and stiff movement
Many infected horses will show no clinical signs. In rare cases the disease can cause severe clinical signs or death in young foals.
EVA is spread through mating, artificial insemination, contact with aborted foetuses, fomites and also on the breath of infected animals. Most countries require pre-export testing of stallions before they can be imported.
Mares recover quickly from infection, nevertheless, they are infectious for up to two weeks post infection and can spread the pathogen to their foals through milk; to other susceptible animals through aerosol or nose to nose contact; or to a stallion from further mating in that period. In rare cases the disease can cause severe clinical signs or death in young foals.
Horse owners must remain vigilant to threat of EVA
Anyone who suspects that their animals are showing signs of the disease should immediately report it to their nearest DAERA Direct Office or to the DAERA helpline on 0300 200 7840.
Prevention
You can help prevent the disease spreading by:
- vaccinating stallions against the disease - talk to your vet for advice
- practising good biosecurity at your premises
- owners of mares and stallions are urged to have their animals tested before they are used for breeding
The above information is included in our one page leaflet – print this and keep it handy, or put a copy on your noticeboard.
Single Lifetime Identification Document for Equines (“Horse Passports”)
All equines in Northern Ireland need to have a Single Lifetime Identification Document (commonly referred to as a “horse passport”) to identify them.
Further information on how to obtain a horse passport.
More useful links
International-Codes-of-Practice-2025_ITBA.pdf
HBLB International Codes of Practice | Home
Horse Illnesses: Equine Disease Prevention | The British Horse Society