Cholera is a bacterial disease (vibrio cholerae) that causes diarrhea, vomiting, and leg cramps.  A person can get Cholera by drinking contaminated water or eating contaminated food.  During an epidemic, the contamination usually comes from human feces.  Since cholera causes severe dehydration, complete rehydration is the only treatment.  If treated this way, less than 1% of patients die.  A prepackaged mixture of sugars and salts is mixed with water and drunk in large amounts to rehydrate the victim.

Currently there are epidemics in Latin America and Africa, with no signs of the end so far.  During the 1800's, cholera raged through the United States.  Cholera is usually found in unsanitary areas of developing countries.  Because cholera is such a problem, travelers to other countries need to take special precautions.