EIA Lethal for Oklahoma Horses

Update

September 3, 2016

A second Oklahoma horse is dead after being euthanized due to testing positive for equine infectious anemia (EIA).

Details are limited, but state officials said the Quarter Horse located in McCurtain County was 13-years-old.

We are unable to confirm if this horse was one of the original sold, due to the holiday weekend.


The Oklahoma State Veterinarian’s office confirms an Atoka County horse was euthanized due to testing positive for equine infectious anemia (EIA). It is the first case of EIA in Oklahoma this year.

Assistant State Veterinarian Michael Herrin, DVM says the EIA-positive horse’s owner decided to sell his “small number of horses” since he wasn’t using them. “These horses had not ever had a coggins test.”

The horses had their blood pulled at the sale. A Coggins test determines the presence of EIA. The test revealed a 14-year-old Quarter Horse mare was positive for the viral disease resulting in the mare’s euthanasia.

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. EIA attacks the horse’s immune system.

Biting insects transmit EIA including horse flies and deer flies. Sharing infected needles between horses can also lead to the virus.

There is no cure or vaccine to prevent EIA.

In Oklahoma, all horses must have a negative EIA test within 12 months to change ownership, cross state lines or attend an equine event.