Development of multiplex RT-PCR method for rapid differentiation of NDV virulent strains from avirulent strains

Four specificoligonucleotide primers were designedaccording to the gene sequences of Newcastle disease virus(NDV) and the sequence difference at fusion gene cleavage sites between virulent and avirulent strains.A multiplex RT-PCR method was developed to differentiate virulent NDV strains from avirulentNDV strains.Results showed that a specific band of 442 bp and a common band of 671 bp were amplified from the virulent NDV strains,while a specific band of 252 bp and a common band of 671 bp were amplified from the avirulent NDV strains,and as little as 100 pg of NDV RNA can be detected in a few hours,by the developed multiplex RT-PCR method.