Fig. 2

Neighbor-joining phylogenetic tree based on the comparison of Babesia microti 18S rRNA gene sequences obtained in this study with B. microti reference strains. Babesia duncani WA1, Babesia crassa-like pathogen (Babesia sp. strain H110), Babesia venatorum, Babesia divergens and Babesia sp. XXB/Hangzhou were used as the outgroup. The number on each branch denotes the percent occurrence in 1 000 bootstrap replicates. Black squares stand for sequences identified in this study. Gray dots indicate human B. microti babesiosis in China. Branch lengths are drawn proportional to the estimated sequence divergence. Phylogenetic tree based on maximum parsimony method was also conducted to examine the effect of the resulting phylogenetic tree (data not shown)