Cholera is a water borne disease caused by Vibrio cholerae.
The main symptom of Cholera is diarrhoea. This is caused by movement of electrolytes from the epithelial cells into the lumen of the gut, subsequently follwed by water.
The Cholera toxin increases the activity of adenylate cyclase. This results in greater production of cyclic AMP (cAMP) and cAMP activates Protein Kinase A (PKA) in CFTR cells.
In the CFTR cell PKA leads to the opening of chloride channels and chloride ions move from the cell into the lumen. Chloride ions are negatively charged and create an electrochemical gradient.
Positively charged sodium ions also move into the lumen in order to balance this electrochemical gradient.
The movement of sodium increases the osmolarity in the lumen and water then moves from the intracellular fluid into the extracellular