However, Sojka cautioned that if a horse is treated for six to eight weeks without improvement, treatment probably will not be successful. However, not all horses return to 100 percent capacity. Once there has been nerve damage, it can't be repaired. Janssen, too, treats horses for 90 to 120 days with about an 80 percent success rate, but he said some horses have shown signs of relapse once treatment was stopped. Horses get it by mistake, Sojka said.
Possums acquire the disease by eating infected birds.
Up to 76 percent of the horses in Indiana may be exposed to this parasite, according to a preliminary study of serum samples from horses throughout the state that was conducted by Dr. Michel Levy, Purdue large animal internal medicine specialist. Levy tested serum samples drawn for Coggins tests, a test for Equine Infectious Anemia that is required for the sale, interstate transportation, and entry of a horse in shows and other competitions. We plan to continue the study by having vets take blood from horses that are known to be healthy. Levy said he also hopes that this follow-up work either will confirm or dispel early indications that EPM seems more prevalent in the northern half of the state than in the southern half. Even though a large percentage of Indiana's equine population may be exposed, the number of horses that actually develop the disease is much lower.