Cholera is an infection of the intestines by the bacterium Vibrio cholerae. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea that lasts a few days. Vomiting and muscle cramps may also occur. Diarrhea can be so severe that it leads within hours to severe dehydration and electrolyte imbalance. This may result in sunken eyes, cold skin, decreased skin elasticity, and wrinkling of the hands and feet. The dehydration may result in the skin turning bluish. Symptoms start two hours to five days after exposure. Cholera is caused by a number of types of Vibrio cholerae, with some types producing more severe disease than others. It is spread mostly by water and food that has been contaminated with human feces containing the bacteria. Insufficiently cooked seafood is a common source. Humans are the only animal affected. Risk factors for the disease include poor sanitation, not enough clean drinking water, and poverty. There are concerns that rising sea levels will increase rates of disease. This disease is diagnosed by the discovery of these bacteria in the stool of the test subject. A rapid test is available but is not as accurate.