Oklahoma Horse Tests Positive for Equine Infectious Anemia A veterinarian pulls blood for a Coggins test.

Deadly EIA Confirmed in Colorado Horse


A horse located at Arapahoe Park in Colorado tested positive for Equine Infectious Anemia (EIA). Horses at the Aurora-based racetrack are under a hold order restricting their movement until the Colorado Department of Agriculture completes its investigation.

The affected horse had a negative Coggins test in May 2015, according to state officials. It has only been in Colorado less than 60-days and originated from an out-of-state track.

EIA is a viral disease, also known as swamp fever. It attacks the horse’s immune system and is transmitted by biting insects – primarily horse and deer flies. It can also be transmitted through infected needles shared between horses.

There is no cure or vaccine to prevent EIA. Affected horses can carry the disease without symptoms for years or they may become acutely or chronically infected. Signs of the disease include fever, depression, anemia, and dependent edema, sometimes progressing to loss of condition, lethargy, and anorexia.

There are no treatment options for infected horses so the United States Department of Agriculture requires euthanasia or strict lifelong quarantine for EIA-positive horses. Studies show that a 200-yard separation between an isolated positive EIA horse and other horses prevents transmission of the disease.

To help prevent the disease, veterinarians recommend insect control, good sanitation, and testing new horses with a Coggins test before bringing them onto your property. They say it is important to only use new, clean needles and syringes on every horse.

In 2015, there were 69 new cases of EIA positive horses on 36 premises in the United States.