Fig. 17From: Diversity and distribution of type A influenza viruses: an updated panorama analysis based on protein sequencesPhylogenetic diversity and distribution of N1 subtype IAVs based on NA sequences. N1 subtype IAVs were classified into three lineages, N1.1, N1.2 and N1.3, largely corresponding to avian, human, and classical swine N1 subtype IAVsBack to article page