title: Characterization of a highly pathogenic avian influenza H5N1 virus sublineage in poultry seized at ports of entry into Vietnam.
abstract: Highly pathogenic avian influenza H5N1 virus was detected in poultry seized at two ports of entry located in Lang Son Province, Vietnam. Sequence analysis of the hemagglutinin (HA) genes from five H5N1 virus isolates and ten PCR amplicons from chicken cloacal samples revealed their close phylogenetic relationship to clade 7 H5N1 HA genes. However, these HA genes exhibited extensive genetic divergence at both the nucleotide and amino acid levels in comparison to previously described clade 7 viruses; e.g., A/chicken/Shanxi/2/2006. In addition, hemagglutination inhibition tests revealed antigenic differences between these and previously isolated H5N1 viruses from Vietnam. These results indicate that viruses with clade 7 HA are evolving rapidly in poultry in Southeast Asia.
authors.affiliation: National Centre for Veterinary Diagnostics, Department of Animal Health, Hanoi, Vietnam.
authors.forename: Tung
authors.initials: T
authors.lastname: Nguyen
authors.forename: C Todd
authors.initials: CT
authors.lastname: Davis
authors.forename: William
authors.initials: W
authors.lastname: Stembridge
authors.forename: Bo
authors.initials: B
authors.lastname: Shu
authors.forename: Amanda
authors.initials: A
authors.lastname: Balish
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Inui
authors.forename: Hoa T
authors.initials: HT
authors.lastname: Do
authors.forename: Huong T
authors.initials: HT
authors.lastname: Ngo
authors.forename: Xiu-Feng
authors.initials: XF
authors.lastname: Wan
authors.forename: Margaret
authors.initials: M
authors.lastname: McCarron
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Lindstrom
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Cox
authors.forename: Cam V
authors.initials: CV
authors.lastname: Nguyen
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Klimov
authors.forename: Ruben O
authors.initials: RO
authors.lastname: Donis