Detection of the bovine leukaemia virus by the polymerase chain reaction.

The polymerase-chain reaction was applied for detection of provirus DNA of the bovine leukaemia virus (BLV). A short fragment of 292 bp including region R and U5 LTR 5' of BLV was amplified, and the optimum parameters of amplification of this fragment were established. Electrophoresis revealed the presence of the 292 bp fragment from the leucocytes of four out of six cows showing a positive serological response to BLV antigens. Application of the polymerase-chain reaction in diagnosis of bovine leukaemia is suggested.