RESUMEN
A total of 34 clinical samples and four Marek's disease virus (MDV) vaccines were tested using primer BamH1/BamH2 in layer birds of poultry. Out of 34 samples tested for detection of MDV, 32 samples produced approximately 434 bp product. All the three HVT vaccines as well as SB-1 (MDV-2) vaccine failed to produce the expected amplicons, there by proving negative for the targeted 132 bp repeats of MDV genome by the primers BamH1/BamH2. Resultant PCR products of the field samples were purified and sequenced and resulted in 378 bp long sequences. PCR was found very satisfactory in detecting the presence of MDV either in feather follicle or in tissue samples. Sequencing study has proved beyond doubt that the two representative samples contained two 132 bp repeats indicating the virulent nature of the field virus.
