Dendrogram showing genetic similarity between 343 isolates of <i>V. cholerae</i> O1 derived from MLVA.

<p>Sequence data of repeats on the five loci for each isolate were counted and imported into BioNumerics software version 6.1. Clustering analysis was performed using the unweighted pair group with arithmetic averaging (UPGMA) with a categorical similarity coefficient. <i>V. cholerae</i> O1 isolate MLVA types of the El Tor variant were grouped into 2 major clusters, I and II.