The potent enterotoxin choleragen is well defined. Binding via B leads to penetration of the A1 peptide, which enzymatically transfers ADP-ribose from NAD to a GTP regulatory protein. Gastric acidity plays an important role in preventing cholera infection. Also, genetic factors may be important since the toxin must bind to specific cellular receptors in order to function. Secretory antitoxin IgA may also play a role.
Transmission of disease is primarily via water that has been contaminated by human feces.
Carriage of vibrios is rare. Gastrointestinal symptoms and the presense of a rice water stool are presumptive for cholera. Direct examination of the feces may indicate vibrios. Sanitary measures are most important in controlling cholera outbreaks. The shear volume of liquid and concentration of viable organisms precludes measures for decontamination.