DIRECT USE OF CELL LYSATES IN PCR-BASED D IAGNOSIS OF BOVINE LEUKEMIA-VIRUS INFECTION

Polymerase chain reaction (PCR) has been used for direct detection of bovine leukemia virus (BLV) proviral DNA in cattle, but it is still ma inly used for experimental research One bottleneck for routine diagnos is of BLV by PCR has always been the isolation and purification of DNA . We compare the use of not purificated with highly-purified DNA in th e PCR-based diagnosis of BLV infection. DNA extracted from whole blood by chloroform extraction (CP-DNA) and DNA prepared only by osmotic sh ock, washing, heating and freezing procedures (RPoS-DNA), were utilize d. Fifteen cattle well characterized serologically were investigated f or BLV-provirus with PCR using this different DNA preparations. With b oth methods all but one investigated animal were correctly identified. It was estimated that in case of CP-DNA PCR 10 BLV-provirus copies we re sufficient to obtain a positive result. The sensitivity of RPoS-DNA PCR was similar. Because of the greater practicability of the latter technique we used it in a small field study with ten cattle. All serol ogically positive animals were correctly identified by the PCR In addi tion one seronegative animal was found to carry BLV-provirus. Therefor e RPoS-DNA PCR might be a good tool for the routine diagnosis of BLV-i nfected cattle.