The Coggins test checks for Equine Infectious Anemia (EIA) antibodies in the horse's blood, and samples must be tested by a state approved lab. EIA is a viral disease with no vaccine and no cure, though a percentage of infected horses appear to recover. It is because of these healthy appearing carriers that we must test. The disease is spread by horseflies. If they bite an infected horse and then bite a healthy horse within thirty minutes the disease gets transmitted. With acute infection the horse has fever, depression, no appetite and will not be positive on the EIA test for a month and a half, if he lives that long. Some infected horse will having recurring bouts with weight loss, ventral edema (swollen belly and legs) and anemia.