Fig. 6From: Diversity and distribution of type A influenza viruses: an updated panorama analysis based on protein sequencesPhylogenetic diversity and distribution of H9 subtypes of IAVs based on HA sequences. H9 subtype IAVs were classified into two primary lineages, H9.1 and H9.2. H9.1 corresponded to some H9 subtype AIVs circulating worldwide. H9.2 corresponded to many AIVs circulating in the Eastern HemisphereBack to article page