While cholera may have been killing people as far back as 400 B.C., it didn't start affecting ... which then produces a toxin in the small intestine that leads to the severe diarrhea and rapid ...

Enterotoxins (cholera toxin [CT] or STb), which selectively upregulate ... CT and LTs consist of an A-subunit (28 kDa), and five B-subunits (11 kDa each) assembled in a pentamer (AB5 structure).