Seroprevalence of Small Ruminant Lentivirus (Maedi-Visna) Infection Among Sheep in Médéa, North-Central Algeria

Respiratory diseases represent a major cause of mortality and morbidity in sheep, causing significant economic losses. Among these is small ruminant lentivirus infection (Maedi-visna), a viral disease with worldwide distribution but limited data in Algeria. A sero-epidemiological survey was conducted in Médéa (Algeria) to investigate the presence of this disease. For this purpose, 202 blood samples from 22 sheep farms were analyzed by ELISA technique. The serological results revealed a herd seroprevalence of 50% and an individual seroprevalence of 13.37%, with a seroprevalence rate of 22,69% among infected herds. Furthermore, all sera that tested positive with the IDEXX ELISA showed negative results when subjected to confirmatory testing using a recombinant protein-based ELISA targeting European strains of Maedi-visna virus and Caprine arthritis encephalitis virus. These findings suggest circulation of Maedi-visna virus in extensive farming systems within Médéa and indicate that local viral strains may differ genetically from European strains.