title: Emergence and dissemination of clade 2.3.4.4 H5Nx influenza viruses-how is the Asian HPAI H5 lineage maintained.
abstract: Highly pathogenic avian influenza (HPAI) A(H5N1) viruses containing the A/goose/Guangdong/96-like (GD/96) HA genes circulated in birds from four continents in the course of 2015 (Jan to Sept). A new HA clade, termed 2.3.4.4, emerged around 2010-2011 in China and revealed a novel propensity to reassort with NA subtypes other than N1, unlike dozens of earlier clades. Two subtypes, H5N6 and H5N8, have spread to countries in Asia (H5N6), Europe and North America (H5N8). Infections by clade 2.3.4.4 viruses are characterized by low virulence in poultry and some wild birds, contributing to wide geographical dissemination of the viruses via poultry trade and wild bird migration.
authors.affiliation: Food and Agriculture Organization of the United Nations (FAO), Regional Office for Asia and the Pacific, Bangkok, Thailand. Electronic address: Filip.Claes@fao.org.
authors.forename: Filip
authors.initials: F
authors.lastname: Claes
authors.affiliation: Food and Agriculture Organization of the United Nations (FAO), Viale delle Terme Di Caracalla, Rome 00153, Italy.
authors.forename: Subhash P
authors.initials: SP
authors.lastname: Morzaria
authors.affiliation: Influenza Division, Centers for Disease Control and Prevention, USA. Electronic address: rdonis@cdc.gov.
authors.forename: Ruben O
authors.initials: RO
authors.lastname: Donis
mesh_terms: D000818:Animals; D000835:Animals, Wild / Q000821:virology; D001208:Asia / Q000453:epidemiology; D001717:Birds; D021821:Communicable Diseases, Emerging; D004196:Disease Outbreaks; D005838:Genotype; D006801:Humans; D009980:Influenza A virus / Q000145:classification* / Q000235:genetics*; D005585:Influenza in Birds / Q000453:epidemiology / Q000635:transmission / Q000821:virology; D007251:Influenza, Human / Q000453:epidemiology* / Q000635:transmission / Q000821:virology*; D016865:Reassortant Viruses