RT Journal Article SR Electronic(1) A1 Le, Quynh Mai A1 Ito, Mutsumi A1 Muramoto, Yukiko A1 Hoang, Phuong Vu Mai A1 Vuong, Cuong Duc A1 Sakai-Tagawa, Yuko A1 Kiso, Maki A1 Ozawa, Makoto A1 Takano, Ryo A1 Kawaoka, YoshihiroYR 2010 T1 Pathogenicity of highly pathogenic avian H5N1 influenza A viruses isolated from humans between 2003 and 2008 in northern Vietnam JF Journal of General Virology, VO 91 IS 10 SP 2485 OP 2490 DO https://doi.org/10.1099/vir.0.021659-0 PB Microbiology Society, SN 1465-2099, AB 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., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.021659-0