[The bovine immunodeficiency virus: 1990-1992 update]

Substantial progress has been shown on the bovine immunodeficiency-like virus (BIV) in 1990-1991 and up to mid-1992. The genomic sequences of BIV were analysed in detail and several subgenomic RNAs were identified. Nucleic acid molecular probes, PCR (polymerase chain reaction) amplification and a novel Western blotting procedure have been of great assistance for the experimental diagnosis of BIV. Antibody response after BIV infection has shown that antibodies to p26 antigen were always present in naturally and experimentally infected animals. The experimental infection of sheep, goats and rabbits was confirmed. BIV causes an infection with no pathognomonic clinical signs in cattle and sheep for at least 3 and 4 years, respectively. Finally, there is not yet any evidence of BIV immune response disturbances similar to that of human AIDS.