Equine infectious anemia (EIA) is a retroviral disease of equids that may be characterized by acute and/or chronic recurring clinical signs including fever, anemia, edema and cachexia in some animals. Many horses have very mild or inapparent signs on first exposure, and carry this virus subclinically. The owners of these animals are unlikely to realize that they are infected unless serological testing is done. All infected horses, including those that are asymptomatic, become carriers and are infectious for life. Infected animals must either be destroyed or remain permanently isolated from other equids to prevent transmission.
Iowa State University
Iowa State University Center for Food Security and Public Health, "Equine Infectious Anemia" (2009). Center for Food Security and Public Health Technical Factsheets. 58.