Figure. A. Phylogenetic tree of partial E (1172-nt) gene sequences, shwoing Ixodes ricinus–transmitted strains (red) and I. persulcatus–transmitted strains (green). The tree was reconstructed by the Bayesian Markov chain Monte Carlo method in BEAST (http://beast.bio.ed.ac.uk). Maximum clade credibility tree with an arbitrary root is shown with mean branch lengths, and Bayesian posterior probabilities are given at nodes when >0.7. Country of origin and isolation year are indicated. Four strains from Simo are shown; Simo-48 and Simo-9 were identical to Simo-38. Yellow shading, tick-borne encephalitis–endemic areas; red line, I. ricinus distribution; green line, I. persulcatus distribution; LPR, Lappeenranta. Scale bar indicates number of substitutions per site.