patients, chlorea, Bagladesh

Patients receive treatment for water borne diseases at the International Centre for Diarrhoeal Disease Research, Bangladesh in 2007 in Dhaka, Bangladesh. A flood set off a huge outbreak of cholera.

David Greedy/Getty Images News/Getty Images

The name "cholera" may invoke images of Charles Dickens' fictional slums, but when a natural disaster knocks out public water supplies anywhere in the world, you can bet public health officials are on the lookout for this fast-killing disease.

Cholera outbreaks kill about 120,000 people a year, but they infect 3 million to 5 million people per year. It turns out that cholera stays asymptomatic (causing no symptoms or harm), in about 75 percent of its hosts. The unknowing carriers pass the bacterium through their feces, which can contaminate water supplies and rapidly infect entire communities [source: WHO].

When cholera does turn virulent, the results are swift and horrible. Victims suffer acute, watery vomiting and diarrhea, which can dehydrate them to lethal levels in a matter of hours. Antibiotics and oral or intravenous (IV) hydration can save victims, but these remedies can be difficult to come by after a flood, earthquake or other natural disaster that leaves available drinking water open to fecal contamination [source: National Library of Medicine].

Communities that prepare disaster response plans can develop strategies for getting clean water in an emergency, thereby preventing cholera outbreaks. But given the unpredictable nature of natural disasters, it's only a matter of time before an earthquake or typhoon once again leaves a community vulnerable to this ancient killer.