Yan's commentary article entitled "Sustained local diversity of Vibrio cholerae O1 biotypes in a previously cholera-free country," is now available in mBio. This commentary is for a recently published study by Dr. Seon Young Choi and colleagues (University of Maryland), also in mBio, on three decades of V. cholerae monitoring from environmental and clinical sources in Mexico. This long-term effort surprisingly found a large number of non-toxigenic V. cholerae strains that are very closely related to the pandemic agents of cholera. Yan speculates that these strains could serve as progenitors for novel toxigenic lineages through horizontal gene transfer in environmental reservoirs. He suggests that widespread and large environmental sampling efforts are needed to detect the presence of these elusive strains, which, incidentally, is exactly what his lab is doing!