Equine infectious anaemia (swamp fever) — the facts

Equine infectious anaemia (EIA), also known as swamp fever, is a viral disease that attacks the horse’s immune system. There is no cure and no vaccine for this viral infection, which is caused by a retrovirus closely related to the HIV virus in humans.

EIA is often fatal to horses but does not affect humans. Symptoms include a reoccurring fever and anaemia. However, horses can also carry the virus without displaying any clinical signs and once they have become carriers, they remain infectious for life. For this reason all infected animals must be humanely destroyed to control the spread of disease.

Blood-sucking insects, such as horse flies, are the most common transmitters of the virus. It can also be transmitted through the use of contaminated blood or blood products, instruments or needles. Pregnant mares may pass the disease to their foals in the womb.

EIA was first identified in France in 1843, and the last outbreak in England was in 1976. The virus is found worldwide and there was a serious outbreak in Ireland in 2006. It is a notifiable disease in the UK. If you suspect that your horse may be suffering from the disease you must immediately notify the duty vet in your local Animal Health Office (check on the Defra website or in the Yellow Pages for contact details).

EIA is confirmed through a blood test called the Coggins test. If EIA is confirmed then Defra can order the destruction of the horse, regardless of the owner’s wishes. If the power to slaughter is invoked, the Animal Health Office will organise for the horse to be put down and for the carcass to be safely removed.

Horses that have been in contact with a horse that has tested positive for the infection will be kept under restrictions and tested until they are confirmed to not be carriers. Horses will not be culled just because they have been in contact with an infected horse.

For more information visit the Defra website