Abstract
Newcastle disease virus (NDV) is an enveloped RNA virus causing the respiratory system disease of the avian. The isolate Wang-kung of NDV was isolated from an outbreak in Taiwan in 1999, this isolate could escape from the challenge of the antibody produced from the velogenic vaccined NDV isolate. To identify the variant of the new Taiwan NDV isolate, we purified the RNA genome of five different NDV strains, the isolate Wang-kung, Zhao-zhou, and the highly virulent NDV reference strain Sato, Ishii, and the lentogenic NDV strain Ishii. After amplifying the matrix (M), fusion (F), and hemagglutinin- neuraminidase (HN) gene fragments by RT-PCR, the sequences were aligned and analyzed. We found the nuclear localization signal in the M gene fragment products had no significant variant. Besides, the amino acid sequences of the F2/F1 cleavage site in the F gene fragments and the HN gene fragments were much variable between NDV isolate Wang-kung and other reference strains, E104G and S139A in the predicted F gene fragment product, and A182T and T257I in the pepsin cleavage site of the predicted HN gene fragment product. NDV isolate Wang-kung is a new variant in Taiwan and different from the reference strains using for the vaccine of the chickens. NDV isolate Wang-kung from the 10-days chicken embryo and the chicken embryo fibroblast cell are all the same in the nucleotide sequences. The different incubation conditions will not affect the gene sequences of NDV isolate Wang-kung.