DEVELOPMENT OF PCR ASSAYS FOR DETECTION O F EHV-1, BRSV AND PESTIVIRUSES

A polymerase chain reaction assay based on primers selected from the v iral gI glycoprotein gene detected 3 fg pure BHV-1 DNA, 0.1-1.0 TCID50 or a single infected cell. No amplification was observed with DNA fro m BHV-2, BHV-3, BHV-4, OHV-1 or OHV-2. However, a fragment of the corr ect size (468 bp) was amplified using DNA from herpesviruses isolated from reindeer, red deer and goat. The PCR assay was able to detect vir us in nasal swabs 1-14 days after experimental infection of cattle and there was a good correlation when PCR was compared to virus isolation for the detection of BHV-1 in clinical field samples. Detection of BH V-1 in fetal bovine serum and semen samples was also successful. PCR d etecting a broad range of BVDV, BDV and HCV was developed. Of six sets of primers selected from different parts of the pestivirus genome the best results were provided by a pair 324/326 from the highly conserve d 5-non-coding region which gave an amplification with all 129 isolate s tested. This panel consisted of 79 isolates from cattle, 33 from pig s and 17 from sheep. Differentiation between viruses was achieved by c leavage of the PCR-ampllfied products (288 bp) with the restriction en donucleases Aval and Bgll. The BVDV products were cleaved by Aval, HCV by Bgll and Aval. Both enzymes, Aval and Bgll, did not cut the BDV pr oducts.