Molecular Detection and Characterization of Hemagglutinin-neuraminidase (HN) and Fusion (F) Genes of Newcastle Disease Virus (NDV) from Duck in NER India

Background: Newcastle disease is one of the major highly contagious disease of birds only next to the highly pathogenic avian influenza virus infection. Ducks are found to be natural reservoirs transmitting the virus to other birds-in-contact. The present study was conducted with the aim to isolate the NDV virus from free ranging ducks and detection of the genotype and pathotype based on HN and F genes. Methods: The virus was isolated in chicken embryo fibroblast (CEF) primary cell culture and confirmed by cytopathic effects as well as by hemagglutination and hemagglutination inhibition tests. Molecular detection was performed using primers specific for HN and F genes. Amplified partial HN and F genes were cloned and sequenced. Phylogenetic tree was prepared based on both partial HN and F genes. Deduced amino acid alignment of protease cleavage site of F protein was performed to determine the strain. Result: The isolated virus could be confirmed by CPE as well as molecular detection by PCR. The target genes, partial HN and F genes exhibited an amplicon of 652 bp and 534 bp, respectively by PCR. On phylogenetic analysis, the present isolate was found to be genotype Xlll and on cleavage site analysis of fusion protein, which was found to be similar in pattern with velogenic pathotype of NDV.