The Utah State Veterinarian has confirmed four horses with equine infectious anemia (EIA). The horses were gathered with a band of feral horses and sold at auction in Uintah County. A mare and foal among the band were resold the next day in Box Elder County to a Kansas buyer, prompting Coggins tests. The tests came back positive. Eighteen additional horses were exposed; five were euthanized.

Horses that went through the auction the same day have been contact traced and tested for EIA; all are negative and awaiting a 60-day retest. One animal that was transported to Colorado is being tested.

Additional horses from the feral band of domestic horses were rounded up and three foals confirmed positive and were euthanized. The remaining band will be checked and tested.

About EIA

Equine infectious anemia is a viral disease that attacks horses’ immune systems. The virus is transmitted through the exchange of body fluids from an infected to an uninfected animal, often by blood-feeding insects such as horseflies. It can also be transmitted through the use of blood-contaminated instruments or needles.

A Coggins test screens horses’ blood for antibodies that are indicative of the presence of the EIA virus. Most U.S. states require horses to have proof of a negative Coggins test to travel across state lines.

Once an animal is infected with EIA, it is infected for life and can be a reservoir for the spread of disease. Not all horses show signs of disease, but those that do can exhibit:

• Progressive condition loss;
• Muscle weakness;
• Poor stamina;
• Fever;
• Depression; and
• Anemia.

EIA has no vaccine and no cure. A horse diagnosed with the disease dies, is euthanized, or must be placed under extremely strict quarantine conditions (at least 200 yards away from unaffected equids) for the rest of his life.