Indiana Horse Tests Positive for Equine Infectious Anemia
A 6-year-old Quarter Horse gelding in Lake County, Indiana, tested positive for equine infectious anemia (EIA) on July 19.

Officials subsequently retested the index horse and tested and quarantined 10 exposed horses at the same premises. The National Veterinary Services Laboratories (NVSL) in Ames, Iowa, confirmed that both the suspect Quarter Horse’s initial and second samples tested positive on agar gel immunodiffusion (AGID) testing. Officials are performing additional trace-back work, because the premises’ owner maintains facilities in both Indiana and Illinois; however, the owner stated that the horse had not been moved recently.

Veterinarians euthanized the positive horse on July 29 and will test the remaining horses when the quarantine expires 60 days from the affected horse’s diagnosis. Routine Coggins testing continues to be the most effective method of EIA control, said Sandy Norman, DVM, director of the Indiana State Board of Animal Health’s companion and equine division.

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 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.

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 disease spread. 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 from unaffected equids) for the rest of his life.