Seroepidemiologic survey of captive old‐world primates for antibodies to human and simian retroviruses, and isolation of a lentivirus from sooty mangabeys (Cercocebus atys)

Sera from 526 Old‐World monkeys and apes, representing 50 species and 20 genera and living in US zoos and vivaria, were screened for antibodies to HTLV‐I, HTLV‐III/LAV, and simian‐AIDS retrovirus, type I (SRV‐I). Sera were screened initially by ELISA, and ELISA‐positive sera, as well as ELISA‐negative sera from cage contacts, were further tested by Western blotting. A large number of false‐positive and a small number of false‐negative ELISA sera were identified. Although most true positive reactions were directed to a single retrovirus, a number of individuals from 4 species were positive for more than one retrovirus. Specific seroreactivity to HTLV‐1 was found in 39/526 (7%) animals of 15 species. True positive reactions to SRV‐1 were found in 21/516 (4%) animals, including talapoins and 2 species of macaques. Specific serologic reactions to HTLV‐III/LAV were detected in 23/526 (4%) monkeys. Many of the HTLV‐III/LAV seropositive animals were from one mixed‐species zoo exhibit, containing sooty mangabeys, mandrills, Kolb's guenons, and talapoins. A type D virus was isolated from the blood of 3/10 SRV‐1 antibody‐positive Tonkeana macaques, but from none of 11 seropositive talapoins. A lentivirus was isolated from the blood of 4/7 HTLV‐III/LAV seropositive sooty mangabeys, but not from seropositive talapoins in the same exhibit or from 2 seropositive colobus from another zoo. The sooty mangabey lentivirus produced generalized lymphadenopathy, leukopenia, and decreased levels of T4 lymphocytes in 2 experimentally infected rhesus macaques.