Detection of amantadine-resistant variants among avian influenza viruses isolated in North America and Asia

M gene phylogenetic tree for H7 North American isolates (amantadine-resistant variants are shown in red)

M gene phylogenetic tree for H9 Asian isolates (amantadine-resistant variants are shown in red)

M gene phylogenetic tree for H5 Asian isolates (amantadine-resistant variants are shown in red)