Double trouble

IN A world full of dread diseases, cholera is among the nastiest afflictions. Vibrio cholerae, the bacterium responsible for such misery, does little harm in its natural environment—floating about with other microorganisms in oceans and estuaries. But when it finds its way into the human gut, through contaminated food or water, it can cause enormous damage. Vibrio comes equipped with several toxic proteins and other lethal accessories that allow it to hang about and destroy the intestinal lining. The result is severe diarrhoea, vomiting and dehydration which kills up to half its victims in days unless they are treated quickly with oral salts or intravenous fluids to rehydrate them.