Molecular analysis of H7 avian influenza viruses from Australia and New Zealand: genetic diversity and relationships from 1976 to 2007

Full genome sequencing of 11 Australian and one New Zealand subtype H7 avian influenza A isolates has enabled the comparison of sequences from each of the genome segments to other sequenced subtype H7 avian influenza A. The inference of phylogenetic relationships for each segment has been used to develop a model of the natural history of these viruses in Australia. The Australian H7 hemagglutinins form a monophyletic clade, consistent with the long-term, independent evolution due to geographic isolation. Based on the analysis of the other available H7 hemagglutinins sequences, the three other geographic regions for which similar monophyletic clades have been observed were confirmed; these regions are Eurasia (Africa, Europe and Asia), North America and South America. Analysis of datasets of H7N1, H7N3, H7N7 neuraminidase sequences revealed congruent relationships indicating a similar pattern of geographically constrained independent evolution for each of the neuraminidase subtype datase...