Why "Red hot" bacterial infection causes loss of water. Osmatic water flow why diarrhea may occur?

Answer 1

The classic example is diarrhea caused by cholera.

Cholera toxin turns on the cGMP signal without allowing it to shut off. cGMP causes the sodium channels in the intestinal epithelium to open, flooding the intestinal lumen with sodium. Osmosis kicks in, and to balance out the Na+, water is released into the intestinal lumen. So as the intestines lose sodium, copious amounts of water are lost with it. The sick person is subject to dehydration and hypokalemia.