n. an acute infection of the small intestine by the bacterium Vibrio cholerae, which causes severe vomiting and diarrhoea (known as ricewater stools) leading to dehydration. The disease is contracted from food or drinking water contaminated by faeces from a patient. Cholera often occurs in epidemics; outbreaks are rare in good sanitary conditions. After an incubation period of 1–5days symptoms commence suddenly; the resulting dehydration and the imbalance in the concentration of body fluids can cause death within 24 hours in severe cases if untreated. Initial treatment involves replacing the fluid loss by oral rehydration therapy; tetracycline eradicates the bacteria and hastens recovery. The mortality rate in untreated cases is over 50%. Vaccination against cholera is effective for only 6–9 months.