FIG. 5.

Adaptive evolution and periodicity of EV-71. (A) Phylogeny of the longitudinally sampled EV-71 subgenogroup C1, together with a comparable phylogeny of the human influenza A virus. Population sequences from 73 individuals of the human influenza A virus (subtype H3N2) hemagglutinin (HA) gene (∼1.7 kb) isolated from six countries across Asia and sampled between 1985 and 2007 were downloaded from the NCBI's Influenza Virus Resource (7). Trees were plotted using PAUP*, version 4.0 beta (78), and scale bars represent 0.02 nucleotide substitutions per site. (B) The annual incidence of EV-71 infections in Japan from 1982 to 2008. EV-71 isolations/detections are reported by public health institutes and compiled by the Infectious Disease Surveillance Center (IDSC) of the National Institute of Infectious Diseases, Tokyo (idsc.nih.go.jp/iasr/index).