Phylogenetic Analysis And Characterization Of Genotype â…¨ Newcastle Disease Virus Isolated From Wild Birds In The Middle Migration Area Of China

There are three of eight global migratory routes through our country, in which the migratory routes of East Asia to Australia, mainly from Siberia through New Zealand and the central of China, finally back to Siberia. In order to understand the infection and spread of genotype Ⅸ Newcastle disease virus(NDV) in wild birds of the eastern part of China, our laboratory increased the sampling range on the basis of previous studies. Since 2011, 300 throat swabs and cloacal swabs of healthy birds(including 7 orders, 18 families and 28 kinds) were taken from Heilongjiang, Jilin, Liaoning, Hebei, Shanxi, Henan, Shaanxi and other provinces of the central region of China. 5 wild genotype Ⅸ NDV strains were isolated and identified through chick separation method, hemagglutination, hemagglutination inhibition assay and RT-PCR. The isolation rate was 1.67%. The viruses sourced from resident birds( red-billed blue magpie, sparrow, rock dove) and migrant(Peace Bird, blackbird). ICPI index showed NDV / Bohemian Waxwing / CH(JL) / 14 /(2013), NDV / Rock Pigeon / CH(JL) / 20 /(2013), NDV / Eurasian Tree Sparrow / CH(SX) / 27 /(2013) have the virulent characteristics, NDV / Red-billed Blue Magpie / CH(XZ) / 2 /(2012), NDV / Common Blackbird / CH(SX) / 7 /(2013) is avirulent.The nucleotide homology of F gene of the 5 NDV isolates was 95.9%~100.0%, and the nucleotide homology with ZJ1、B1、clone 30、F48E9、La Sota、V4(Queensland)were 83.4%~86.7%、86.0%~89.2%、85.9%~89.3%、96.0%~99.8%、85.8%~89.2%、88.5%~91.9% respectively. The ORF of HN gene of all isolates were amplified by PCR,sequenced and analyzed for their genetic relationship by performing the alignment and constructing phylogenetic tree based on the sequences. The nucleotide and amino acid homology of NDV isolates and F48E9 was 99.6 %-99.8% and 99.1%-99.7% respectively, but 90.2 %-91.8% and 87.9 %- 88.5% compared with La Sota, Clone 30 and B1. All the isolated C-terminus of HN gene have the same termination codons, which is coincided with the reference virulent strains F48E9, belong to subgenotype C. The phylogenetic tree based on the nucleotide sequences of HN gene revealed that the 5 isolates of NDV and F48E9 were the same subgenotype viruses.The results showed that the genotype IX NDV were widely distributed in the healthy wild birds on the migratory routes East AsiaAustralia in the eastern part of China. Although the relationship between the genotype IX NDV and genotype VII strains and traditional vaccines were distant, the chicken exhibited moderate or low virulence, indicating that wild birds NDV has unique molecular characteristics and pathogenicity. So it is necessary to strengthen the monitor of wild birds NDV in this area.