title: Molecular characterization and pathogenicity of swine influenza H9N2 subtype virus A/swine/HeBei/012/2008/(H9N2).
abstract: The H9N2 subtype influenza virus (IV) is a remarkable member of the influenza A viruses because it can infect not only chickens, ducks and pigs, but also humans. Pigs are susceptible to both human and avian influenza viruses and have been proposed to be intermediate hosts for the generation of pandemic influenza viruses through reassortment or adaptation to the mammalian host. To further understand the genetic characteristics and evolution, we investigated the source and molecular characteristics of the H9N2 subtype swine influenza virus (SIV), and observed its pathogenicity in BALB/c mice. The BALB/c mice were inoculated intranasally with 100 median mouse infectious dose of A/swine/HeBei/012/2008/(H9N2) viruses to observe the pathogenicity. The HA, NP, NA and M gene were cloned, sequenced and phylogenetically analyzed with related sequences available in GenBank. The infected mice presented with inactivity, weight loss and laboured respiration, while the pathological changes were characterized by diffuse alveolar damage in the lung. The nucleotide and deduced amino acid sequence of HA, NP, NA and M gene was similar with that of A/chicken/Hebei/4/2008(H9N2). The HA protein contained 6 glycosylation sites and the motif of HA cleavage site was PARSSR GLF, which is characteristic of low pathogenic IV. In the HA, NP, M and NA gene phylogenetic trees, the isolate clustered with A/chicken/Hebei/4/2008(H9N2). The isolate possibly came from A/chicken/Hebei/4/2008(H9N2) and was partially varied during its cross-species spread.
authors: Department of Veterinary Medicine, HeBei North University, Hebei, People's Republic of China.
authors: Zhang
authors: Z
authors: Rui-Hua
authors: Cui
authors: C
authors: Hong-Yu
authors: Xu
authors: X
authors: Ming-Ju
authors: Li
authors: L
authors: Kai
authors: Chen
authors: C
authors: Hua-Lan
authors: Wang
authors: W
authors: Cun-Lian
authors: Wei
authors: W
authors: Dong
authors: Li
authors: L
authors: Cun-Xin
authors: Xu
authors: X
authors: Tong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002642:Chick Embryo; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D005260:Female; D005814:Genes, Viral; D053127:Influenza A Virus, H9N2 Subtype / Q000302:isolation & purification* / Q000472:pathogenicity* / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000235:genetics / Q000662:veterinary*; D058873:Pandemics; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013552:Swine / Q000821:virology; D013553:Swine Diseases / Q000453:epidemiology / Q000821:virology*; D014779:Virus Replication