Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Model for acquisition of ctxAB by the two V. cholerae O1 biotypes. An ancestral V. cholerae isolate gave rise to the classical and El Tor biotypes, which were subsequently independently infected with divergent CTXφs. CTXφ probably arose from a precursor CTXφ that acquired the CT genes by imprecise excision from a unknown donor strain.
