Cholera

Abstract Cholera is a water-borne, diarrhoeal disease caused by the bacterium Vibrio cholera. For illness to occur, humans must consume vast amounts of the bacteria. The cholera bacteria must also possess a cluster of genes involved in creating the toxin co-regulated pilus, as well as expressing the gene for cholera enterotoxin. Treatment for cholera involves giving victims oral rehydration to help them survive and antibiotics to shorten the infectious period. In mid-19th-century London, John Snow discovered that cholera was spread by a contagious agent, and localized this to a particular water pump during a cholera outbreak. Moreover, cholera helped inspire Koch’s postulates, which state the requirements for identifying a particular organism as the causative agent of a disease. Cholera evolves antibiotic resistance by horizontal gene transmission. Cholera is infected by viruses called phages, which can also move genes around in the bacterial population, and which may eventually be used to treat infection as well. Because cholera spreads through water, hygiene and water purification are the best ways to control its transmission.