Progressive control of equine infectious anaemia through more accurate diagnosis

EQUINE infectious anaemia (EIA) is a persistent viral infection of equids. The causative agent, equine infectious anaemia virus (EIAV), is a lentivirus in the family Retroviridae , subfamily Orthoretrovirinae. All lentiviruses cause persistent infections, and most lentiviruses cause a slow, progressive disease that frequently results in death. In contrast, EIA results in an acute phase, followed by recurrent but eventually subsiding, clinical disease periods. These horses become persistently infected inapparent carriers. The clinical signs of EIA were first described in horses in France in 1843 (Lignee 1843) and the causative agent was shown to be a filterable agent in 1904 (Vallee and Carre 1904). EIA can be diagnosed on the basis of clinical signs, pathological lesions, serology and molecular methods. Infected horses remain viraemic carriers for life and, with very rare exceptions, yield a positive serological test result. Most horses develop antibodies that can be detected by agar gel immunodiffusion test (AGIDT) on average up to 24 days after infection, but sometimes it can take up to three months for antibodies to be detected. The antibody response …