Phylogenetic analysis of small ruminant lentiviruses from Southern Brazil

The first lentivirus isolated from sheep in Brazil was analysed phylogeneti cally. Evolutionary trees of the proviral 597 nucleotide gag and 432 nucleo tide pol sequences obtained by the maximum likelihood method demonstrated t hat the sheep isolate clustered with prototype Maedi Visna virus whereas th ree lentiviruses isolated from goats in the same geographic region were clo se to caprine arthritis encephalitis prototypes. A subsequent comparison of sequence data of these viruses with those contained in the EMBL sequence d atabase revealed that, in contrast to caprine prototypic viruses, all proto typic Maedi Visna viruses contain a deletion of six nucleotides in the gag gene resulting in the deletion of two residues in the central region of cap sid protein. This deletion may be a useful marker in the analysis of small ruminant lentiviruses, especially when considering possible transmission of lentiviruses between sheep and goats. (C) 2001 Elsevier Science B.V. All r ights reserved.