Pathogenesis-Cholera

Because there are strains of V. cholera that are either an organism in the environment and a pathogen in a human body (serotype 01 and 0139), it is important to determine what differentiates a pathogenic strain from a non-pathogenic strain. The pathogenic V. Cholerae have genes which code or have instructions to produce the cholera toxin.- Cholera toxin is the protein complex secreted by the V. cholerae once inside the intestine. And, most importantly, it is what is responsible for the immune response and symptoms of Cholera. 1. V. cholerae enters the human body through ingestion of contaminated food or water. 2. Enters the intestine and imbeds itself in the villi, or finger-like projections that protrude from the lining. This is where the bacteria releases the cholera toxin. 3. The release of the cholera toxin induces a physiological response from the host, which includes stimulation of the mucosal lining of the intestine to secrete fluids to try and "flush out" the bacteria. This fluid is what causes the watery diarrea and vomitting. This is what also causes the extreme dehydration. Both the watery diarrhea and the dehydration are due to osmosis.-
 * __Stages of pathogenesis__**

Osmosis is the movement of water across a membrane and naturally occurs to achieve homeostasis. The water travels from high concentration to low concentration, which is also low solute concentration to high solute concentration. When V. cholerae is in the intestine and secretes the Cholera toxin, the body recognizes the intestine as having a high solute concentration. Because of this, the osmotic flow travels from outside of the intestine into the intestine, or from low solute concentration to high solute concentration, to achieve homeostasis again. The increase in fluids in the intestine is what makes the diarrhea watery. It is also the reason for dehydration; instead of harboring the fluids to keep the body hydrated, the body is using those fluids to flush out the V. cholerae and ultimately regain homeostasis.- The vomiting can also lead to dehydration from the loss of fluids through the regurgitation.
 * __Osmosis: cause of watery diarrhea and dehydration__**

__**Citations**__ www.ph.ucla.edu/epi/snow/lancet363_223_233_2004.pdf http://microbewiki.kenyon.edu/index.php/Vibrio_cholerae https://www.healthtap.com/user_questions/20008-what-is-the-relationship-between-osmosis-and-diarrhea