Equine Viral Arteritis

Equine Viral Arteritis (EVA) - a warning for mare owners

With the breeding season now upon us, the British Equestrian Federation and The British Horse Society have been working together, in tandem with their primary welfare objectives, on an initiative to inform breeders or individuals thinking of breeding their mare of the dangers of EVA and the measures which can be taken to minimise the risk of spreading this disease.

EVA occurs in equine populations worldwide. It is a notifiable disease in stallions. In stallions, mares and youngstock signs of infection vary from highly visible to none at all, and even when there appears to be no evidence of infection the disease may still be transmitted. Infection may cause abortion in pregnant mares and can in some cases be fatal.

Spread of the disease is preventable by ensuring that horses are free from the disease (by blood testing) and by vaccination of stallions.

The Horserace Betting Levy Board (HBLB) annually updated Codes of Practice provide detailed recommendations for the prevention of spread of this disease, which for domestic mares means blood testing  "all mares after 1st January and within 28 days before use for breeding activities. The mare should not be used until the results are available".

Furthermore when sending your mare to stud, you should be aware of the EVA status of the stallion you intend to use on your mare. For domestic stallions HBLB state "after 1st January in any year, all unvaccinated stallions and teasers should be blood tested. Do not use a stallion for breeding activities until the result is available".

EVA is a serious viral disease of horses which is still relatively rare in the UK but the risks of it becoming more widespread has potentially very serious welfare and economic effects.

It is therefore crucial that everyone in the UK involved in the horse industry is familiar with the clinical signs of the disease, the way in which the disease is spread and the control measures which should be used to minimise the risk of EVA spreading within the UK horse population.

More information can be found via the following websites:

For a detailed veterinary briefing note on EVA, its dangers and minimising its spread, visit http://www.bef.co.uk or www.bhs.org.uk