Pathotypic characterization of Newcastle disease virus isolated from vaccinated chicken in West Java, Indonesia

This research was conducted to differentiate and characterize eight Newcastle disease virus (NDV) isolates collected from vaccinated chicken at commercial flocks in West Java, Indonesia, in 2011, 2014 and 2015 by pathotype specific primers. A total of eight NDV isolates collected from clinical outbreaks among commercial vaccinated flocks in West Java, Indonesia, in 2011, 2014, and 2015 were used in this study. Reverse transcription-polymerase chain reaction was used to detect and differentiate virulence of NDV strains, using three sets of primers targeting their M and F gene. First primers were universal primers to detect NDV targeting matrix (M) gene. Other two sets of primers were specific for the fusion (F) gene cleavage site sequence of virulent and avirulent NDV strains. Our results showed that three isolates belong to NDV virulent strains, and other five isolates belong to NDV avirulent strains. The nucleotide sequence of the F protein cleavage site showed K/R-R-Q/R-K-R/G-F on NDV virulent strains and G-K/R-Q-G-R-L on NDV avirulent strain. Result from the current study suggested that NDV virulent strain were circulating among vaccinated chickens in West Java, Indonesia; this might possess a risk of causing ND outbreaks and causing economic losses within the poultry industry.