Equine viral arteritis: how to spot and report the disease

Equine viral arteritis (EVA) is a contagious disease caused by the equine arteritis virus.

The virus occurs worldwide, including mainland Europe, in thoroughbred and non-thoroughbred populations. It does not affect humans.

Clinical signs

Signs of equine viral arteritis can include:

• conjunctivitis (bloody tissue around the eye known as ‘pink eye’)
• swelling of testicles or udder, also around eyes and lower legs
• abortions (failed pregnancies in mares)
• fever and runny nose
• depression
• lethargy and stiff movement

Some infected horses will show no clinical signs.

How equine viral arteritis is spread

EVA can be spread through:

• mating
• artificial insemination
• contact with aborted foetuses
• contaminated equipment
• on the breath of infected animals for up to two weeks

Stallions can carry the disease for extended periods without showing clinical signs. They can spread the disease through sexual contact or if their semen is used to artificially inseminate a mare.

Mares can spread the disease during pregnancy to their foals, or through milk, or to a stallion from further mating.

Vaccination

You can help prevent the disease by vaccinating horses and ponies against the disease.

Human health implications

There are no human health implications because the disease is not zoonotic.

How to control the disease

If the disease is confirmed the outbreak will be controlled in line with the contingency plan for exotic notifiable diseases.

You can help prevent this disease spreading by following the Horserace Betting Levy Board’s (HBLB) Codes of Practice.

Legislation

In Scotland, EVA is notifiable by law under the Equine Viral Arteritis Order 1995. Under the Order, anyone who owns, manages, inspects or examines a horse must notify their local Animal Health and Veterinary Laboratories Agency Office when:

• they suspect the disease in a stallion, either on the basis of clinical signs or following blood or semen testing
• they suspect disease, either on the basis of clinical signs or following blood testing, in a mare that has been mated or artificially inseminated within the past 14 days

Biosecurity

The policy on disease control is that prevention is better than cure. This approach works by reducing the chances of a disease entering the animal population, and if it does then it can be quickly spotted and dealt with through the preventative measures.

Biosecurity is about being aware of the ways disease can spread, and taking every practical measure to minimise the risk of disease spreading.