“Coggins” is the name of a test that looks for antibodies to a viral disease called equine infectious anemia (EIA). The t4est itself can only be run by a state or state/federal approved lab. A positive result has serious consequences, since there is no treatment for this disease.
The virus destroys red blood cells and platelets, which can lead to fatal anemia. If an infected horse survives, he becomes an EIA carrier for life and a source of infection for other horses. Biting flies, such as horseflies and deer flies, spread the disease on their mouthparts: A fly bites an infected horse and subsequently bites a noninfected horse. The virus can only survive approximately four to six hours on the fly, so transmission is usually within close range, such as horses pastured together.
The virus is present throughout the world. North America has strict testing. Thankfully most states, provinces and territories are completely free of this disease, but outbreaks have happened. If a horse test positive for EIA, state regulatory agents are notified and the horse is either quarantined for life or put down. Approximately 20 years ago, in the province of Manitoba, an outbreak occurred and all horses were tested. Any positive horse was either destroyed or quarantined for life. Since quarantine is difficult, most horses were destroyed.
When traveling across state lines, most states require proof that your horse has had a negative Coggins test within the last six to 12 months. International movement also requires negative testing. Some horse show managers require proof of a negative Coggins test prior to the start of competition. Some states require negative Coggins when horses go through ownership changes. The aim of such rigorous testing is to eliminate the disease and protect the horse population in general.