Ashley Griffin, University of Kentucky

Equine infectious anemia (EIA), or swamp fever, is a viral disease that occurs worldwide. The disease is usually spread by horse flies biting an infected horse, then biting a healthy horse. The disease can also be transmitted by the use of nonsterile needles and blood-contaminated surgical instruments.

Clinical Signs


1. high fever
2. labored breathing
3. pounding heartbeat and exhaustion
4. anemia.


Horses that recover usually remain carriers of the disease. The death rate is low.



There is no specific treatment or vaccine for EIA. Treatment consists of supportive therapy of intravenous fluids and vector control. Infected horses should be promptly isolated.





There is no cure for EIA, so prevention is the key to controlling the disease. The Coggins test is a simple blood test that is widely accepted as a way of determining carriers of the disease. The Coggins test is often required to transport, show, sell, or board a horse. Coggins tests should be updated yearly. Owners of positive horses have to make the choice to put the horse down (euthanized) or have the animal permanently quarantined. Transportation of positive horses is prohibited.