FIG 1.

Position of ZTox in the phylogeny of pandemic V. cholerae. A maximum-likelihood phylogenetic tree from ∼1,200 toxigenic clinical isolates of V. cholerae with overrepresentation of contemporary clinical isolates from outbreaks in sub-Saharan Africa (light blue). The preseventh pandemic strain A6 (31) was used as an outgroup. Scale bar represents the mean number of nucleotide substitutions per site. ZTox clusters with 7PET wave 3 strains, particularly with isolates from nearby African countries (sublineage T13) and South Asian regions of V. cholerae endemicity that seed long-range transmission events. The PIC018 Inaba strain used for vibriocidal assays is also depicted.