Identification of different BLV provirus isolates by PCR, RFLPA and DNA sequencing

A first attempt for the investigation of molecular epidemiology of BLV was carried out. PCR amplicons of a part of the env gene of BLV isolated from 3 09 cattle of different geographical origin were compared with known BLV env sequences. Using RFLPA most of the PCR products can be assigned to the Aus tralian, the Japanese or the Belgian subgroup. A phylogenetic tree resultin g from the comparison of the sequences of these env fragments demonstrates the relations and differences between and within the subgroups.