Fig. 3

Phylogenetic trees of HA nucleotide sequences of pH1N1 and H3N2 viruses. HA sequences of pH1N1 (n = 512) and H3N2 (n = 239) reported from MENA region between 2009 and 2017 were compared to vaccine strains recommended by WHO (denoted with green triangles) and the reference strains of known clades as reported in WHO Influenza Center London, indicated by navy blue circles [25]. Phylogenic trees were generated using maximum likelihood method by GTR + G model using in MEGA7 software. Bootstrap values of 1000 replicates and only values larger than 50 are indicated at the nodes. At the major nodes are the signature amino acid changes in different colors according to antigenic site: Red for Sa (pH1N1) and A (H3N2), blue for Ca (pH1N1) and B (H3N2), green for C (H3N2). Scale bar represents approximately 0.005 nucleotide difference between close relatives