Once infected, horses remain infected for life, often without showing any signs of the disease. The EIA virus is transmitted by infected blood transferred by biting insects, nonsterile needles, and contaminated equipment or surgical instruments. The disease occurs throughout most of the United States but is most common in states surrounding the Gulf of Mexico.
Many carriers show no signs of the disease.
Diagnosis Equine infectious anemia is diagnosed by a blood test called the Coggins' test , so named for Dr. Leroy Coggins, the veterinarian who developed the test. In the first 2 months after infection, the horse may have a negative Coggins' test. If an infected horse is not immediately destroyed, it can be donated to a research facility or placed in lifelong quarantine in a screened facility at least 200 yards from other horses. Be sure the seller provides documentation of a negative Coggins' test before you purchase a new horse, donkey, or mule. All equine events should require negative Coggins' test for each participant.