Maedi-visna virus (MVV) infection of sheep is characterized by slowly progressive arthritis, pneumonia, mastitis and encephalomyelitis. The causative agent of the disease is a virus classified as lentivirus, a subgroup of retroviruses. MVV infection is found all over the world. 

This classification also includes caprine arthritis encephalitis virus (CAEV), which manifests itself in adult goats mainly in the form of severe arthritis of the carpal joint ("big knee"). 

Animals with CAEV become emaciated despite an intact appetite, and show poor milk yield. Serologic surveys show that CAEV is widely disseminated in goat herds on different continents. 

The Kernel CAEV/MVV Ab Test is an enzyme linked immunosobent assay (ELISA) for the detection of antibodies against Caprine Arthritis Encephalitis virus (CAEV) and Maedi-Visna virus (MVV) in serum and plasma samples of goat and sheep.