Causes

A bacterium called Vibrio cholerae causes cholera infection. The deadly effects of the disease are the result of a toxin the bacteria produces in the small intestine. The toxin causes the body to secrete enormous amounts of water, leading to diarrhea and a rapid loss of fluids and salts (electrolytes).

Cholera bacteria might not cause illness in all people who are exposed to them, but they still pass the bacteria in their stool, which can contaminate food and water supplies.

Contaminated water supplies are the main source of cholera infection. The bacterium can be found in:

• Surface or well water. Contaminated public wells are frequent sources of large-scale cholera outbreaks. People living in crowded conditions without adequate sanitation are especially at risk.
• Seafood. Eating raw or undercooked seafood, especially shellfish, that comes from certain places can expose you to cholera bacteria. Most recent cases of cholera in the United States have been traced to seafood from the Gulf of Mexico.
• Raw fruits and vegetables. Raw, unpeeled fruits and vegetables are a frequent source of cholera infection in areas where there's cholera. In developing countries, uncomposted manure fertilizers or irrigation water containing raw sewage can contaminate produce in the field.
• Grains. In regions where cholera is widespread, grains such as rice and millet that are contaminated after cooking and kept at room temperature for several hours can grow cholera bacteria.