False positives typically occur in foals nursing infected mares, and consequently the foals have circulating colostral antibodies for the EIA infection from the infected mare in their immune system. The incidence of false positives can be decreased or eliminated by testing foals that are at least six to nine months old. By that time colostral antibodies are no longer present in the foal's immune system. This can be accomplished by euthanasia, removal for slaughter, or quarantine in the herd of origin. Methods to control the spread of EIA To effectively control the spread of EIA in the equine population, positive individuals must be detected and removed from the population.
More testing is required of the entire population to effectively detect infected animals.
This is especially true of animals carrying the inapparent form of the disease, as they are infected carriers without showing detectable clinical signs of the infection. There are several preventative management measures equine owners can take to decrease the risk of their animals contacting the disease. One important measure is establishment of an effective fly control program. Blood sucking insects are the primary transmitters of EIA, so decreasing the presence of these pests, can decrease the risk of equine animals getting the disease. Effective fly control programs can utilize foggers, fly repellants, and electronic or automatic fly control systems in barns.