Equine Infectious Anaemia (EIA) is a non-contagious, but infectious disease of horses and other equines. It is a blood-borne disease, which causes anaemia (low red blood cell count) amongst other signs.
Although not currently known to be in the UK since the last outbreak in 2012, the virus is prevalent in mainland Europe as well as the rest of the world, and is notifiable by law in the UK. The disease does not affect humans.
The virus is mainly spread from animal to animal through the blood of biting flies, but contaminated blood products (needles, transfusion etc..) and transplacental (from mare to foal) spread has also occurred. Generally the disease lasts from approximately a couple of days to 3 weeks, but has been seen to also last a couple of months.
The clinical signs of the disease depend on the stage of the virus:
- Acute form: pyrexia, depression, ataxia, rapid weight loss and occasionally haemorrhage; disease may be fatal within days with no sign of anaemia. Acutely infected horses carry high levels of virus in the blood and are potentially infectious to other horses and donkeys.
- Chronic form: recurring cycles of anaemia, oedema, weight loss and lethargy are seen; mares may abort.
- Subclinical form: infected horses may not show any clinical signs of disease, but remain seropositive asymptomatic carriers.
Diagnosis cannot be made on clinical signs alone. A blood sample taken by a veterinarian and sent to a laboratory is the only assured method of diagnosis. The Coggins Test is currently the only test recognised officially for the purpose of international movement of horses; it specifically detects antibodies against EIA.
There is currently no treatment available for EIA; if a horse is found positive by the Coggins test, compulsory euthanasia must be carried out. Therefore, the prevention of infection is vital; fly control is of utmost importance, especially during the summer months.
In infection is suspected, movement of horses on or off the premises must be stopped, the horse isolated, and your veterinarian should be called. Disinfection, biosecurity and good stable hygiene should be carried out. Horses that have come into contact with an infected horse or a horse which is suspected of being infected must be quarantined for a minimum of 90 days post-exposure.
Stopping the spread of EIA is every horse owners' responsibility. It remains one of the most important viral diseases to test for when travelling with your horse abroad; therefore remember to be vigilant even at home or away!