Table of Contents
Scholarly Research Exchange
Volume 2008 (2008), Article ID 802317, 7 pages
Research Article

Sequence and Phylogenetic Analysis of Three Isolates of Avian Influenza H9N2 from Chickens in Southern China

1Department of Biotechnology, Guangxi Veterinary Research Institute, 51You Ai Road, Nanning, Guangxi 530001, China
2Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Road, Storrs, CT 06269-3089, USA

Received 27 February 2008; Accepted 7 April 2008

Copyright © 2008 Zhixun Xie et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Three isolates of H9N2 subtype of influenza virus have been isolated from chickens in Guangxi province. In this study, eight full-length genes of each of the H9N2 isolates, A/Chicken/Guangxi/1/00, A/Chicken/Guangxi/14/00, and A/Chicken/Guangxi/17/00, were obtained. Sequence analysis and phylogenetic studies were conducted by comparing eight genes of each isolate with those of the available H9N2 strains at GenBank. Results showed a high degree of homology between the Guangxi isolates and isolates from Guangdong and Jiangsu provinces, suggesting that Guangxi isolates originated from the same source. However, the eight genes of these three isolates from Guangxi were not in the same sublineages in the phylogenic trees, which suggest that they were products of natural reassortment between H9N2 avian influenza viruses from different sublineages. The 9 nucleotides ACAGAGATA encoding amino acids T, E, I were absent between nucleotide 205 and 214 in the open reading frame of NA genes in the Guangxi isolates. AIV strains that infect human have in their HA proteins, Leucine at position 226. The analysis of deduced amino acid sequence of HA proteins of C/GX/1/00, C/GX/14/00, and C/GX/17/00 showed that the position 226 of these isolates was glycine instead of leucine, suggesting that these three isolates differ from H9N2 AIV strains isolated from human infections.