The World Health Organisation estimates there are between 3 & 5 million cases of cholera worldwide every year. Cholera is an acute diarrhoeal disease caused by the bacteria Vibrio cholerae. It is usually transmitted via infected water that has been contaminated by faeces and less commonly via food. It is for these reasons that the disease is more common in areas of the world with poor sanitation such as sub-Saharan Africa, South-East Asia and the Middle East. After an incubation period that may last from a few hours to 5 days, severe cholera is characterised by a sudden onset of watery diarrhoea accompanied by nausea and vomiting.