title: Pathogenicity of highly pathogenic avian H5N1 influenza A viruses isolated from humans between 2003 and 2008 in northern Vietnam.
abstract: Vietnam is one of the countries most affected by highly pathogenic H5N1 influenza A viruses. To evaluate the potential pathogenicity in mammals of H5N1 viruses isolated from humans in Vietnam, we determined the sequences of all eight genes of 22 human isolates collected between 2003 and 2008 and compared their virulence in mice. The isolates were classified into clade 1 and clade 2.3.4 and differed in pathogenicity for mice. Whilst lysine at position 627 of PB2 (PB2-627K) is a critical virulence determinant for clade 2.3.4 viruses, asparagine at position 701 of PB2 and other unknown virulence determinants appear to be involved in the high pathogenicity of clade 1 viruses, warranting further studies to determine the factors responsible for the high virulence of H5N1 viruses in mammals.
authors.affiliation: National Institute of Hygiene and Epidemiology (NIHE), Hanoi, Vietnam.
authors.forename: Quynh Mai
authors.initials: QM
authors.lastname: Le
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Ito
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Muramoto
authors.forename: Phuong Vu Mai
authors.initials: PV
authors.lastname: Hoang
authors.forename: Cuong Duc
authors.initials: CD
authors.lastname: Vuong
authors.forename: Yuko
authors.initials: Y
authors.lastname: Sakai-Tagawa
authors.forename: Maki
authors.initials: M
authors.lastname: Kiso
authors.forename: Makoto
authors.initials: M
authors.lastname: Ozawa
authors.forename: Ryo
authors.initials: R
authors.lastname: Takano
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kawaoka
mesh_terms: D000818:Animals; D001216:Asparagine / Q000235:genetics; D016000:Cluster Analysis; D004195:Disease Models, Animal; D005838:Genotype; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000302:isolation & purification* / Q000472:pathogenicity*; D007251:Influenza, Human / Q000821:virology*; D008239:Lysine / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000473:pathology / Q000821:virology; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D014744:Vietnam; D014764:Viral Proteins / Q000235:genetics; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics
chemical_list: C057027:PB2 protein, Influenzavirus A; D012367:RNA, Viral; D014764:Viral Proteins; D037521:Virulence Factors; D001216:Asparagine; D012324:RNA-Dependent RNA Polymerase; D008239:Lysine