Cholera is an infection of the guts caused by the bacterium Vibrio cholerae.

People who catch the cholera bacterium, show signs of watery diarrhoea and vomiting. This tends to cause them to lose water faster than they can put it back by drinking and their skin turns a greyish-bluish skin. They die of water loss.

Cholera is present in many untreated waters around the world. It can also be present in food made with untreated water. Some people have a natural immunity to it, so not everyone catches cholera, but of those that do, many die unless they are given a special solution of water and minerals to rebalance their systems and give their natural defences a chance to work against the bacterium. I severe cases they will need antibiotics.

Up to 5 million people are affected by cholera each year and over 100,000 die. It was the illness that made Dr John Snow famous when he was studying the choler outbreak in Victorian London. It was he who discovered that cess pits were placed next to wells, and that contaminated liquids from the cesspits were finding their way into well water, thus spreading the disease. The number of deaths dropped dramatically when he had one well capped off so it could not be used.

Cholera is nowadays a disease of poorer countries that do not have treated water supplies.