Final answer:
Vibrio cholerae releases cholera toxin in the GI tract, causing an influx of ions and water into the intestinal lumen and resulting in severe watery diarrhea ('rice water stool'), dehydration, and electrolyte imbalance. Symptoms can include nausea, vomiting, and abdominal cramps. Prompt treatment is crucial to prevent life-threatening dehydration.
Step-by-step explanation:
Vibrio cholerae targets the tight junctions in the gastrointestinal (GI) tract, more specifically affecting the intestinal epithelial cells. Once V. cholerae has attached to the epithelial cells, it releases cholera toxin, an A-B toxin that triggers an increase in cyclic AMP levels. This activation of adenylate cyclase results in the opening of chloride channels and subsequent efflux of chloride ions into the intestinal lumen, which causes an osmotic movement of water into the lumen as well. The main symptom that arises from this process is profuse watery diarrhea, often described as 'rice water stool,' leading to rapid dehydration and electrolyte imbalance.
V. cholerae can also acquire virulence factors through horizontal gene transfer, which contributes to its pathogenic characteristics. The bacterium can withstand the highly alkaline environments and once in the small intestine, causes symptoms including nausea, vomiting, abdominal cramps, and extreme fluid loss that can be fatal if left untreated.