Vibrio cholerae is the bacterium that causes cholera, a severe diarrheal disease linked to contaminated water.
The comma-shaped bacterium usually spreads when people ingest water or food contaminated with feces. In the small intestine, toxigenic strains produce cholera toxin, which disrupts salt and water movement across intestinal cells. The resulting watery diarrhea can cause dangerous dehydration within hours.
Not every V. cholerae strain causes epidemic cholera. The O1 and O139 serogroups are the main groups associated with large outbreaks, while many other strains live in aquatic environments and cause little or no disease. Cholera is treatable, but rapid replacement of lost fluids is crucial.
The species is also notable for its natural aquatic lifestyle. It can attach to plankton and persist in coastal and estuarine environments, helping explain why cholera outbreaks often follow disruption of water and sanitation systems.