Phylogenetic Analysis of Newcastle Disease Virus Isolated from Vaccinated Chicken in West Java, Indonesia

摘要

Newcastle disease (ND) is a highly contagious disease of poultry worldwide, caused by Newcastle Disease virus (NDV), also known as Avian Paramyxovirus Typel. Newcastle disease virus is responsible for causing significant economic losses to the poultry industry in Southeast Asia including Indonesia. Despite vaccination, outbreaks of ND in vaccinated chicken flocks in Indonesia have been regularly reported. Although the current vaccines are substantially effective, they do not completely prevent infection, virus shedding and disease. The emergence of new virulent genotypes implies that distinct genotypes of NDV are simultaneously evolving at different geographic locations across the globe. The genomic diversity of NDV increases the possibility of diagnostic failures, resulting in unidentified infections. Our study aim to determine the genotype of isolates and to find out phylogeny relationship among NDV isolates compared with other NDV published on the GeneBank. Four characterized isolates used in this study were obtained from the repository of the Laboratory of Immunology, Faculty of Veterinary Medicine, Bogor Agricultural University. Two isolates belong to virulent NDV strain and other two isolates belong to avirulent NDV strain. A set of primer NDV-F-Forward 5'- ATG GGC TCC AAA CCT TCT AC- 3' and NDV-F- Reverse 5'- TTG TAG TGG CTC TCA TC - 3' were used to generate an amplicon targeting 1662 bp. Phylogenetic analyses of the F gene revealed that NDV/Ck/BGR/011 and NDV/Ck/GS/014 belong to genotype VII (sub) genotype (VIIh and VIIi) and NDV/Ck/CJR/015 and NDV/Ck/BGR/015 belong to genotype II. Our study revealed that NDV virulent strains which belong to genotype VII (sub) genotype (VIIh and VIIi) were circulating among vaccinated chicken flocks in West Java, Indonesia. ND outbreaks among vaccinated flocks, suggesting that vaccination strategies not effective in controlling the virus yet.