How does Vibrio Cholerae produce watery diarrhea?

Answer 1

The bacterium Vibrio cholerae does not directly act on our gut to cause the profuse watery diarrhea; instead, it produces a toxin called cholera toxin, which is the actual molecule that initiates the diarrhea symptoms during cholera.

Much like the shiga toxin of Escherichia coli O157:H7 and Shigella dysenteriae, cholera toxin is a G-protein-binding protein. It binds to G-proteins in our cells in the gut, which constantly activates it in its alpha-subunit and beta-gamma subunit activated forms. What results from this constant activation is the constant opening of ion channels in our cells, which then translates into mass diffusion of cellular fluid and electrolytes out of the cell towards the extracellular space. This fluid and electrolyte loss is the watery diarrhea symptom observed in patients with cholera.

Hope this helps!

Answer 2

Just to extend the excelent answer above:

The Beta subunit binds to the surface of the cell, producing a change in the cell that allows the alpha subunit inside, which then disrupts the ion channels in the cell leading to the mass movement of ions out the cell.