title: Genetic analysis of avian influenza A viruses isolated from domestic waterfowl in live-bird markets of Hanoi, Vietnam, preceding fatal H5N1 human infections in 2004.
abstract: The first known cases of human infection with highly pathogenic avian influenza (HPAI) H5N1 viruses in Vietnam occurred in late 2003. However, HPAI H5N1 and low-pathogenic avian influenza (LPAI) H5N2 and H9N3 viruses were isolated from domestic waterfowl during live-bird market (LBM) surveillance in Vietnam in 2001 and 2003. To understand the possible role of these early viruses in the genesis of H5N1 strains infecting people, we performed sequencing and molecular characterization. Phylogenetic analysis revealed that the hemagglutinin (HA) genes of two geese HPAI H5N1 strains belonged to clade 3, and their surface glycoprotein and replication complex genes were most closely related (98.5-99.7% homologous) to A/duck/Guangxi/22/01 (H5N1) virus, detected contemporarily in southern China, whilst the M and NS genes were derived from an A/duck/Hong Kong/2986.1/00 (H5N1)-like virus. The H5 HA gene of the duck HPAI H5N1 strain belonged to clade 5 and acquired a gene constellation from A/quail/Shantou/3846/02 (H5N1), A/teal/China/2978.1/02 (H5N1) and A/partridge/Shantou/2286/03 (H5N1)-like viruses. The phylogenetic analysis further indicated that all eight gene segments of goose and duck HPAI H5N1 and LPAI H5N2 viruses were distinct from those of H5N1 clade-1 viruses known to have caused fatal human infections in Vietnam since late 2003. The duck H9N3 isolates derived genes from aquatic-bird influenza viruses, and their H9 HA belonged to the Korean lineage. The PB2 gene of A/duck/Vietnam/340/01 (H9N3) virus had lysine at position 627. Based on the molecular characterization of specific amino acid residues in the surface and relevant internal protein-coding genes, the Vietnamese H5N1 and H9N3 virus isolates indicated specificity to avian cell surface receptor and susceptibility for currently licensed anti-influenza A virus chemotherapeutics. Our findings suggest that the H5N1 and H5N2 viruses that circulated among geese and ducks in LBMs in Hanoi, Vietnam, during 2001 and 2003 were not the immediate ancestors of the clade-1 viruses associated with fatal human infections in Vietnam. The clade-1 HPAI H5N1 viruses were independently introduced into Vietnam.
authors: Influenza Division, MS-G16, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, NE, Atlanta, GA 30333, USA. Samadhan.Jadhao@ars.usda.gov
authors: Samadhan J
authors: SJ
authors: Jadhao
authors: Doan C
authors: DC
authors: Nguyen
authors: Timothy M
authors: TM
authors: Uyeki
authors: Michael
authors: M
authors: Shaw
authors: Taronna
authors: T
authors: Maines
authors: Thomas
authors: T
authors: Rowe
authors: Catherine
authors: C
authors: Smith
authors: Lien P T
authors: LP
authors: Huynh
authors: Ha K
authors: HK
authors: Nghiem
authors: Diep H T
authors: DH
authors: Nguyen
authors: Hang K L
authors: HK
authors: Nguyen
authors: Hanh H T
authors: HH
authors: Nguyen
authors: Long T
authors: LT
authors: Hoang
authors: Tung
authors: T
authors: Nguyen
authors: Lien S
authors: LS
authors: Phuong
authors: Alexander
authors: A
authors: Klimov
authors: Terrence M
authors: TM
authors: Tumpey
authors: Nancy J
authors: NJ
authors: Cox
authors: Ruben O
authors: RO
authors: Donis
authors: Yumiko
authors: Y
authors: Matsuoka
authors: Jacqueline M
authors: JM
authors: Katz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001717:Birds; D002681:China / Q000453:epidemiology; D004372:Ducks / Q000821:virology*; D005777:Geese / Q000821:virology*; D016679:Genome, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics; D053125:Influenza A Virus, H5N2 Subtype / Q000235:genetics; D009980:Influenza A virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D005585:Influenza in Birds / Q000453:epidemiology* / Q000821:virology; D007251:Influenza, Human / Q000453:epidemiology*; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011200:Poultry / Q000821:virology; D011201:Poultry Diseases / Q000453:epidemiology* / Q000821:virology; D016415:Sequence Alignment; D014744:Vietnam / Q000453:epidemiology
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; C109963:hemagglutinin, avian influenza A virus