title: Invasions by Eurasian avian influenza virus H6 genes and replacement of the virus' North American clade.
abstract: The spread of highly pathogenic avian influenza virus (AIV) (H5N1) underlines the potential for global AIV movement through birds. The phylogenies of AIV genes from avian hosts usually separate into Eurasian and North American clades, reflecting limited bird migration between the hemispheres. However, mounting evidence that some H6 sequences from North America cluster with Eurasian subtype H6 sequences calls the strict hemispheric divide into question. We conducted a comprehensive phylogenetic analysis of the extent and timing of cross-hemisphere movements by the H6 gene. Results suggested that Eurasian H6 subtype has invaded North America several times, with the first invasions occurring 10 years before the first detection of invading isolates. The members of the North American clade decreased from 100% in the 1980s to 20% in the 2000s among H6 isolates from North America. Unraveling the reasons for this large-scale gene movement between hemispheres might identify drivers of global AIV circulation.
authors.affiliation: Center for Animal Disease Modeling and Surveillance, University of California School of Veterinary Medicine, Davis, California 95616, USA. hzudohna@ucdavis.edu
authors.forename: Heinrich
authors.initials: H
authors.lastname: zu Dohna
authors.forename: Jinling
authors.initials: J
authors.lastname: Li
authors.forename: Carol J
authors.initials: CJ
authors.lastname: Cardona
authors.forename: Joy
authors.initials: J
authors.lastname: Miller
authors.forename: Tim E
authors.initials: TE
authors.lastname: Carpenter
mesh_terms: D000818:Animals; D001208:Asia / Q000453:epidemiology; D001717:Birds; D005060:Europe / Q000453:epidemiology; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000145:classification / Q000235:genetics*; D005585:Influenza in Birds / Q000235:genetics / Q000635:transmission / Q000821:virology; D007251:Influenza, Human / Q000453:epidemiology / Q000235:genetics* / Q000635:transmission; D009656:North America / Q000453:epidemiology; D010802:Phylogeny