Equine infectious anemia virus (EIAV) is a type of retrovirus of the Lentivirinae subfamily. EIAV infects and replicates primarily in tissue macrophages and integrates into the host genome. Horses infected with EIAV remain infected carriers of the virus for life.
EIAV is transmitted to horses through bites from infected horseflies, deerflies and stable flies.
The incubation period of EIAV is 1 to 3 weeks, but can take up to 3 months in some horses.