As a simian species, the langurs are not known to harbor simian retroviruses, except for one report on a simian Type D endogenous retrovirus from the spectacled langur (Trachypithecus obscurus) from Malaysia. The present report describes for the first time natural infection of the common Hanuman langur (Semnopithecus entellus) from India by a novel simian retrovirus (SRV). The new SRV is phylogenetically related to but distinct from the three molecularly characterized serotypes, SRV 1-3, of the five known serotypes of SRVs, based on sequence analyses from the 3'orf and env regions of the viral genome. The novel SRV isolated from the Indian Hanuman langur is provisionally named SRV-6.

A performance evaluation of a particle agglutination test (PAT), manufactured by Fujirebio Inc., Japan (Serodia-HIV), for antibody to human immunodeficiency virus type-1 (anti-HIV-1) was carried out and compared with a currently available enzyme immunoassay (EIA), manufactured by Genetic Systems Corp., USA, (HIV-1/HIV-2 EIA). Testing 2,878 Indian donor and patient samples, both tests showed 100% sensitivity and comparable specificity (PAT: 99.8%; EIA: 99.7% among donor samples). We conclude that PAT is a specific and sensitive test for anti-HIV-1; it is simple to perform and does not require sophisticated equipment. Hence it is suitable for mass screening of blood donors in a developing country like India, especially in rural areas where presently no HIV-testing facilities are available.