Your Guide to Equine Health Care

EIA Confirmed in Arizona Horse

The horse had recently resided in both Maricopa and Pinal Counties, and 28 horses are now exposed.

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Pinal and Maricopa Counties, Arizona
A horse in Arizona has been euthanized after testing positive for EIA, and 28 horses in Pinal and Maricopa counties are exposed.

An 8-year-old Quarter Horse mare in Arizona was confirmed positive for equine infectious anemia (EIA) on March 15. The disease was detected by pre-movement blood testing collected on March 9 in order for the horse to travel across state lines.

Further investigation revealed that within the last eight months, the positive horse had resided at three premises, two in Pinal County and one in Maricopa County. The 28 other horses at these premises have been tested for EIA and equine piroplasmosis. No further disease detections have been identified. All three premises are under quarantine until a 60-day recheck blood test is performed and all exposed horses test negative again.

The positive index horse has been euthanized.


EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

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.

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 body 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.

Brought to you by Boehringer Ingelheim, The Art of the Horse


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