cholera

Disease caused by infection with various strains of the bacillus Vibrio cholerae, transmitted in contaminated water and characterized by violent diarrhoea and vomiting. It is prevalent in many tropical areas.

The formerly high death rate during epidemics has been much reduced by treatments to prevent dehydration and loss of body salts, together with the use of antibiotics. There is an effective vaccine that must be repeated at frequent intervals for people exposed to continuous risk of infection. The worst epidemic in the Western hemisphere for 70 years occurred in Peru in 1991, with 55,000 confirmed cases and 258 deaths. It was believed to have been spread by the consumption of seafood contaminated by untreated sewage. 1991 was also the worst year on record for cholera in Africa with 13,000 deaths.

The sequencing of the complete cholera genome was completed in August 2000, revealing that many of the genes that enable cholera to attack humans are found on a single chromosome. The discovery should aid the development of a more effective vaccine and other drugs to combat the disease.