Rapid detection and differentiation of Newcastle disease virus isolates bya triple one-step RT-PCR

A triple one-step RT-PCR was developed to screen and differentiate virulent from avirulent Newcastle disease virus (NDV) isolates. Three sets of oligo nucleotides were designed, each specific for amplifying NDV fusion protein gene-specific RNA from virulent, avirulent or all isolates respectively. Th e sensitivity of one-step RT-PCR was determined using viral RNA extracted f rom serially diluted NDV-infected allantoic fluid and found to be 10(-5) HA units. Application of one-step RT-PCR to various NDV samples, including wi ld-type virulent isolates and avirulent vaccine strains, demonstrated the p otential for rapid identification (3-4 h) of NDV isolates as well as the di fferentiation of virulent from avirulent strains.