Maximum likelihood tree of CRF01_AE V3 sequences from Stockholm and Helsinki and of closely related database sequences. The color of each branch represents the country of sampling for Swedish and Finnish sequences, while sequences from other countries are shown in gray. The filled circles next to the tips indicate main drug use. The sampling times for Swedish and Finnish sequences are shown on the right, in gray scale. The trunk, colored pink, describes the relative movement of the epidemic of lineage 2, and the MRCA for the Finnish-Swedish cluster is annotated MRCAScand. The scale at the bottom indicates the number of nucleotide substitutions per site, according to a GTR+I+G model. The tree was rooted using CRF01_AE African sequences 01CD107 (GenBank accession no. AY675602) and 01CM2534 (GenBank accession no. AY180116). Robustness aLRT values of >70%, >80%, and >90% are marked with 1, 2, and 3 asterisks, respectively.