Figure 1. Phylogenetic tree based on the DNA sequences of bvgS.
The lengths of the branches represent the phylogenetic distances. All human B. pertussis (Bp), B. bronchiseptica (Bb) and B. parapertussis (Bpp) isolates are shown in red. The major complexes identified in an earlier study [28] are boxed in colors, and the numbers in parentheses correspond to the sequence types defined in that study.