Naturally occurring Vibrio cholerae

Cholera is a condition caused by a protein exotoxin produced by the bacterium vibrio cholerae. This protein toxin consists of six subunits one A subunit and five B subunits. The B subunits are responsible for the binding of the toxin to cAMP-functioning cells in small bowel of the intestines. The A subunit penetrates the cell and has catalytic activity which attaches the ADP portion of naturally occurring NAD (nicotine-adenosine dinucleotide) to the G-protein complex thereby inhibiting its GTPase activity. This deprives the complex of its "off-switch" for cAMP formation. The effect is the uncontrolled... 

Vibrio cholerae, for example, occurs naturally in freshwater and brackish waters [26,73,132] in associations with planktonic organisms, and is responsible for cholera epidemics and the associated deaths that have occmred in many countries [37,40,149]. 

Fecal coliforms are not good indicators of the presence of pathogenic bacteria (e.g., Vibrio cholerae, V. vulnificus, and V. parahaemolyticus) that are naturally occurring in surface waters. 

Commonly implicated water-borne pathogens include Vibrio cholerae, Cryptosporidium parvum and hepatitis A. The pathophysiology and clinical presentation of these, and numerous other examples, are well described in the wider literature. However, they are also relevant from a biological weapons perspective due to the capacity to cause widespread illness by their intentional release into water supplies. Natural epidemics also occur sporadically throughout the world. Most UK cases are imported by infected travellers. 

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