Coggins Test: Equine Infectious Anemia


The Coggins Test was developed by Dr. Coggins in the 1970’s to detect Equine Infectious Anemia, (EIA). EIA is a debilitating viral disease in horses and donkeys that is transmitted by blood. Usually, EIA is spread by horseflies and deerflies and other blood-sucking insects when they bite and feed on horses. It can also be spread by sharing needles between horses.

Diagnosing EIA can be very difficult because the symptoms are broad and not all horses exhibit similar symptoms; some infected horses may not exhibit any symptoms at all. We recommend contacting your local veterinarian if your horse exhibits any or all of the following symptoms:
• Fever, especially if it exceeds 105°F
• Depression
• Mucosal petechial hemorrhages
• Decreased platelet numbers
• Decreased red blood cell numbers
• Swollen legs, lower chest, and abdomen
• Decreased appetite
• Fatigue, weakness, or decreased stamina
• Rapid breathing
• Sweating
• Rapid weight loss
• Nasal bleeding
• Mucus membranes that are pale or yellow in color
• Weak pulse and / or irregular heartbeat
• Colic
• Abortion

Coggins Test
As a means of identifying and controlling the disease, any horse that crosses state lines must be tested and carry those results with them on the road. Many shows and arenas, like the Weld County Fair and the Colorado State Fair, require horses to be tested prior to entry on the grounds. Any show is at liberty to include the Coggins Test as an entry requirement.

Only a licensed veterinarian who has obtained additional accreditation through the USDA is authorized to perform the Coggins test.

Unfortunately, once a horse is infected with EIA, they are infected for life; the horse can never recover or clear the virus. There is no vaccine or treatment – horses infected with EIA will die from the virus. Because infected horses can spread the disease to healthy ones, there are two very difficult choices when a horse tests positive for EIA:

  1. EIA-positive horses are quarantined for life in a screened stall at least 200 yards away from other animals; “Quarantined: Equine Infectious Anemia” or “Swamp Fever” signs must be posted and transportation of EIA-infected horses is severely restricted
  2. EIA-positive horses are euthanized

Because horses that test positive for EIA will always pose a risk to other horses the American Association of Equine Practitioners, and other federal and state health agencies, recommend euthanasia to ensure the safety of all other horses. It’s an emotionally difficult decision but the only way to eradicate the disease is to eliminate carrier horses.

Your Role
The good news is that due to the diligent efforts of the USDA and State Veterinarians, the disease is very rare and most horses today are at a very low risk. Continued vigilance helps the entire equine industry. If you would like more information about the Coggins test or Equine Infectious Anemia, if your horse needs a Coggins test, or if you would like to have a Coggins test performed for your peace of mind, please contact either of our two on-staff, licensed, and accredited veterinarians.



Recent Posts
Contact Us

Howdy! Send us a quick note or email us at

National Pet Fire Safety Day