Experimental infection of sheep by caprine arthritis-encephalitis virus and goats by progressive pneumonia virus.

The lentiviruses, caprine arthritis-encephalitis virus (CAEV) and progressive pneumonia virus (PPV) of sheep, cause major diseases in their respective hosts; however, the infectivity of these viruses for closely related species has not been determined. Experiments were conducted to determine whether CAEV would infect sheep and whether PPV would infect goats. Upon inoculation with CAEV, lambs developed a nonsuppurative arthritis and antibody to CAEV, and the virus was isolated up to 4 months later. Exposure of 3 lambs to CAEV-infected adult goats did not lead to demonstrable infection after 18 months. Young goats inoculated with PPV replicated the virus and developed arthritis and antiviral antibody. These results demonstrate that these distinctly different lentiviruses may infect and cause diseases in species other than their accustomed host. Presently used techniques may not be effective in differentiating which lentivirus is responsible for infection of sheep and goats. Our results also indicate that mixing sheep and goats may adversely influence attempts to eradicate lentiviruses from these species.