Genetic and antigenic evolution of H9N2 subtype avian influenza virus in domestic chickens in southwestern China, 2013-2016.
H9N2 avian influenza virus (AIV) has caused significant losses in chicken flocks throughout china in recent years. There is a limited understanding of the genetic and antigenic characteristics of the H9N2 virus isolated in chickens in southwestern China. In this study a total of 12 field strains were isolated from tissue samples from diseased chickens between 2013 and 2016. Phylogenetic analysis of the Hemagglutinin (HA) and Neuraminidase (NA) nucleotide sequences from the 12 field isolates and other reference strains showed that most of the isolates in the past four years could be clustered into a major branch (HA-branch A and NA-branch I) in the Clade h9.4.2 lineages. These sequences are accompanied by nine and seven new amino acids mutations in the HA and NA proteins, respectively, when compared with those previous to 2013. In addition, four new isolates were grouped into a minor branch (HA-branch B) in the Clade h9.4.2 lineages and two potential N-glycosylation sites were observed due to amino acid mutations in the HA protein. Three antigenic groups (1-3), which had low antigenic relatedness with two commonly used vaccines in China, were identified among the 12 isolates by antigenMap analysis. Immunoprotection testing showed that those two vaccines could efficiently prevent the shedding of branch A viruses but not branch B viruses. In conclusion, these results indicate the genotype of branch B may become epidemic in the next few years and that a new vaccine should be developed for the prevention of H9N2 AIV.
College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, P. R. CHINA.
Jing
J
Xia
College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, P. R. CHINA.
Jia-Qi
JQ
Cui
College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, P. R. CHINA.
Xiao
X
He
College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, P. R. CHINA.
Yue-Yue
YY
Liu
College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, P. R. CHINA.
Ke-Chang
KC
Yao
College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, P. R. CHINA.
San-Jie
SJ
Cao
College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, P. R. CHINA.
Xin-Feng
XF
Han
College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, P. R. CHINA.
Yong
Y
Huang
D000818:Animals; D000956:Antigens, Viral / Q000235:genetics* / Q000276:immunology; D002645:Chickens; D002681:China; D003429:Cross Reactions; D019143:Evolution, Molecular; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D053127:Influenza A Virus, H9N2 Subtype / Q000145:classification / Q000235:genetics* / Q000276:immunology; D007252:Influenza Vaccines / Q000276:immunology; D005585:Influenza in Birds / Q000276:immunology / Q000821:virology*; D009439:Neuraminidase / Q000235:genetics; D010802:Phylogeny; D011201:Poultry Diseases / Q000276:immunology / Q000821:virology*; D064166:Vaccine Potency; D014764:Viral Proteins / Q000235:genetics
D000956:Antigens, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D014764:Viral Proteins; C109963:hemagglutinin, avian influenza A virus; C487630:NA protein, influenza A virus; D009439:Neuraminidase