Cholera is a bacterial infection of the small bowel that can cause severe diarrhea and dehydration.
There have been seven great pandemics (worldwide epidemics) of cholera in history. The seventh began in 1961, when cholera re-emerged in Indonesia and swept across most of the world, and it still lingers today. At the beginning of the 21st century, cholera infected around 3 million to 5 million people per year worldwide; of these, about 100,000 died.
Cholera settles wherever poor hygiene permits it to infect humans, who appear to be cholera's only hosts. The bacterium that causes cholera is most productive in times of flood and war, since these events can reduce the availability of clean water. Cholera continues to occur in Asia, Africa, the Middle East, and South and Central America. The latest outbreak occurred in Haiti.
Worldwide, cholera kills about 4% of the people who develop severe symptoms. That includes people who are treated too late or inappropriately and those who never reach a doctor. Fewer than 1% of people with severe cholera die if they're quickly and properly treated.