Year-end Sale % OFF 
Abstract
BackgroundWild birds are the major reservoir hosts for influenza A viruses (AIVs) and have been implicated in the emergence of pandemic events in livestock and human populations. Understanding how AIVs spread within and across continents is therefore critical to the development of successful strategies to manage and reduce the impact of influenza outbreaks. In North America many bird species undergo seasonal migratory movements along a North-South axis, thereby providing opportunities for viruses to spread over long distances. However, the role played by such avian flyways in shaping the genetic structure of AIV populations remains uncertain.ResultsTo assess the relative contribution of bird migration along flyways to the genetic structure of AIV we performed a large-scale phylogeographic study of viruses sampled in the USA and Canada, involving the analysis of 3805 to 4505 sequences from 36 to 38 geographic localities depending on the gene segment data set. To assist in this we developed a maximum likelihood-based genetic algorithm to explore a wide range of complex spatial models, depicting a more complete picture of the migration network than determined previously.ConclusionsBased on phylogenies estimated from nucleotide sequence data sets, our results show that AIV migration rates are significantly higher within than between flyways, indicating that the migratory patterns of birds play a key role in viral dispersal. These findings provide valuable insights into the evolution, maintenance and transmission of AIVs, in turn allowing the development of improved programs for surveillance and risk assessment.
Highlights
Wild birds are the major reservoir hosts for influenza A viruses (AIVs) and have been implicated in the emergence of pandemic events in livestock and human populations
Data preparation To investigate the strength of association between viral and bird migration we focused on the internal gene segments of Avian Influenza virus (AIV), encoding the PB2, PB1, PA, NP, and MP (M1 and M2 coding regions were concatenated) proteins
For each gene we found that the two-rate model (TRM) models provided a significantly better fit to the data than the homogeneous rate model (HRM) (LRT p-value
Summary
Wild birds are the major reservoir hosts for influenza A viruses (AIVs) and have been implicated in the emergence of pandemic events in livestock and human populations. Despite their classification into multiple subtypes based on sequence diversity in the hemagglutinin (HA) and neuraminidase (NA) genes, those AIVs sampled from the Western and Eastern hemispheres tend to form distinct monophyletic groups, with relatively infrequent viral movement between hemispheres [14,15,16] This phylogenetic pattern implies that there is a low transmission rate between birds that are located in disjunct localities, in turn suggesting that bird movements, including wild bird migration, between North America and the Old World are Fourment et al BMC Evolutionary Biology (2017) 17:118 limited [17]. It is reasonable to assume that natural physical barriers like extended areas of water and mountain ranges lead to the ecological separation of bird species and, by extension, to their viral populations One such obvious barrier at the continental scale is the presence of avian flyways, which loosely describe the migratory pathways followed by diverse avian species [18]. Because flyway assignments are often only approximate, and the borders between them fluid because they do not reflect absolute physical boundaries, there will be some movement among flyways [19]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
