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Invasions by Eurasian avian influenza virus H6 genes and replacement of the virus' North American clade.

zu Dohna H, Li J, Cardona CJ, Miller J, Carpenter TE - Emerging Infect. Dis. (2009)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Center for Animal Disease Modeling and Surveillance, University of California School of Veterinary Medicine, Davis, California 95616, USA. hzudohna@ucdavis.edu

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.

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Related in: MedlinePlus

Eurasian clade of the phylogenetic tree for all full-length H6 sequences of avian influenza virus (excluding multiple sequences of the same isolate). Black branches indicate isolates from North America, and gray branches indicate isolates from Eurasia. The 7 subclades that invaded North America and their closest Eurasian related clade and bootstrap values are shown on the right. Abbreviations for strain names are listed in the Technical Appendix Table.
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Figure 2: Eurasian clade of the phylogenetic tree for all full-length H6 sequences of avian influenza virus (excluding multiple sequences of the same isolate). Black branches indicate isolates from North America, and gray branches indicate isolates from Eurasia. The 7 subclades that invaded North America and their closest Eurasian related clade and bootstrap values are shown on the right. Abbreviations for strain names are listed in the Technical Appendix Table.

Mentions: The phylogenetic tree of all 291 full-length H6 gene sequences shows a clear division between the Eurasian and North American clades (Technical Appendix Figure 1). Within the Eurasian clade there were 7 monophyletic subclades composed of strains isolated from North America (Figure 2). Six of these 7 subclades had bootstrap support above 90%. Five of these 7 subclades were closely related to isolates in Eurasia. Of these 5 subclades, 3 were most closely related to isolates in East Asia, and 2 were most closely related to clades in Northern Europe. All North American isolates of the 2 subclades most closely related to clades in Europe were found on the East Coast or in the Midwest region of the United States. Most of the isolates from the subclades closely related to isolates in Asia were found in Alberta, Canada, and the West Coast of the United States. The exceptions were 1 isolate from New Jersey and 1 from Delaware, which clustered in subclades with close relatives in Asia (Figure 2).


Invasions by Eurasian avian influenza virus H6 genes and replacement of the virus' North American clade.

zu Dohna H, Li J, Cardona CJ, Miller J, Carpenter TE - Emerging Infect. Dis. (2009)

Eurasian clade of the phylogenetic tree for all full-length H6 sequences of avian influenza virus (excluding multiple sequences of the same isolate). Black branches indicate isolates from North America, and gray branches indicate isolates from Eurasia. The 7 subclades that invaded North America and their closest Eurasian related clade and bootstrap values are shown on the right. Abbreviations for strain names are listed in the Technical Appendix Table.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2744232&req=5

Figure 2: Eurasian clade of the phylogenetic tree for all full-length H6 sequences of avian influenza virus (excluding multiple sequences of the same isolate). Black branches indicate isolates from North America, and gray branches indicate isolates from Eurasia. The 7 subclades that invaded North America and their closest Eurasian related clade and bootstrap values are shown on the right. Abbreviations for strain names are listed in the Technical Appendix Table.
Mentions: The phylogenetic tree of all 291 full-length H6 gene sequences shows a clear division between the Eurasian and North American clades (Technical Appendix Figure 1). Within the Eurasian clade there were 7 monophyletic subclades composed of strains isolated from North America (Figure 2). Six of these 7 subclades had bootstrap support above 90%. Five of these 7 subclades were closely related to isolates in Eurasia. Of these 5 subclades, 3 were most closely related to isolates in East Asia, and 2 were most closely related to clades in Northern Europe. All North American isolates of the 2 subclades most closely related to clades in Europe were found on the East Coast or in the Midwest region of the United States. Most of the isolates from the subclades closely related to isolates in Asia were found in Alberta, Canada, and the West Coast of the United States. The exceptions were 1 isolate from New Jersey and 1 from Delaware, which clustered in subclades with close relatives in Asia (Figure 2).

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Center for Animal Disease Modeling and Surveillance, University of California School of Veterinary Medicine, Davis, California 95616, USA. hzudohna@ucdavis.edu

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.

Show MeSH
Related in: MedlinePlus