colorado horse tests positive for eia

A Weld County, Colorado, horse has tested positive for equine infectious anemia (EIA).

The Colorado Department of Agriculture (CDA) State Veterinarian’s Office received the positive result from the USDA’s National Veterinary Services Laboratory on Aug. 24. Results from a confirmatory retest were received on Aug. 28.

The CDA has quarantined the Weld County facility until it completes further testing.

“The affected horse has been isolated from the remaining horses on the facility, which will be observed and retested in 60 days,” said Colorado State Veterinarian Keith Roehr, DVM. “We are actively tracing movements of the horse and others it came in contact with in Colorado and other states. The disease is most commonly spread by biting flies and we’re still in the midst of Colorado’s fly season.”

On Aug. 27, Wyoming animal health official announced that they had placed a Sweetwater County facility under quarantine after horses residing there were exposed to a Colorado horse that tested positive for EIA. Those horses are scheduled to be tested for EIA on Aug. 30.

EIA 101

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 a 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 EIA. Most U.S. states require horses to have proof of a negative Coggins test in order to travel.

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.

There is no vaccine and no cure. A horse diagnosed with EIA 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.