Caprine Arthritis and Encephalitis

Caprine arthritis and encephalitis (CAE) is an economically important viral disease of goats. The caprine arthritis encephalitis virus (CAEV), a lentivirus; infects its hosts for life. Although most infections are subclinical, a minority of animals develops progressive, untreatable disease syndromes including polyarthritis in adults and encephalomyelitis in kids. This virus also causes indurative mastitis, resulting in decreased milk production. CAEV infections decrease lifetime productivity in dairy goats, particularly when the prevalence of infection is high within a herd. In addition, CAEV is a barrier to the exportation of goats from countries where it is endemic, including the United States. CAEV is closely related to the maedi-visna virus (MVV), which is found most often in sheep. Although documented cases of natural cross-species transmission are currently rare, CAEV can infect sheep and MVV can infect goats. In Switzerland, CAEV has been re-introduced into CAEV-free goat herds by exposure to sheep. In addition, recombination has recently been demonstrated between MVV and CAEV. These findings suggest that eradication programs for either maedi-visna (ovine progressive pneumonia) or caprine arthritis and encephalitis should now address both infections simultaneously.