EIA: What’s the Big Deal?

Find out where veterinarians are seeing an uptick in equine infectious anemia cases.
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EIA: What
Infected horses, like this one at FRIENDS Horse Rescue and Sanctuary, often show no outward signs of disease, but they must be branded as EIA-positive and quarantined for life if not euthanized. | Photo: Courtesy Debbi Beye-Barwick/FRIENDS

Find out where veterinarians are seeing an uptick in equine infectious anemia cases

Each year, like clockwork, our veterinarians take blood samples from our horses during spring health exams. We sign the forms, and off the tubes go to the lab for the Coggins test. We do this year in and year out, with no positives and no questions asked. So why do we keep up with this annual horse care ritual? 

The Coggins test checks for antibodies against the equine infectious anemia virus (EIAV). This virus is significant because much like the human immunodeficiency virus (HIV), its lentiviral cousin, there is no vaccine and no cure. A horse diagnosed positive for equine infectious anemia (EIA) dies, is euthanized, or gets placed under extremely strict quarantine conditions (at least 200 yards away from other equids) for the rest of his life.

How Do Horses Get EIA?

The EIA virus passes from one horse to another via blood. Biting flies, such as horseflies, deerflies, and stable flies, can transmit it after feeding on an infected horse

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Written by:

Nancy S. Loving, DVM, owns Loving Equine Clinic in Boulder, Colorado, and has a special interest in managing the care of sport horses. Her book, All Horse Systems Go, is a comprehensive veterinary care and conditioning resource in full color that covers all facets of horse care. She has also authored the books Go the Distance as a resource for endurance horse owners, Conformation and Performance, and First Aid for Horse and Rider in addition to many veterinary articles for both horse owner and professional audiences.

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