Cholera, a Disease That Keeps Repeating Its History

Medical Author: Charles Davis, MD, PhD
Medical Editor: Melissa Conrad Stöppler, MD

Again, a cholera epidemic strikes a human population. This time the cholera epidemic is in Haiti, a small country that has undergone large disasters. On Jan. 12, 2010, a huge earthquake killed over 300,000 people, leaving Haiti with a huge homeless population and its main city, Port-au-Prince, devoid of most normal services and sanitary conditions. Many city residents left, but the more rural areas were not any better at supplying people with sanitary conditions. Many Haitians simply turned to their largest river in the country for water to drink, bathe, wash clothes, and swim in. This is a perfect environment for the development and spread of cholera and other diseases. As of Oct. 26, 2010, at least 250 people have died from cholera in Haiti.

Researchers speculate that someone imported cholera to Haiti since the disease has not been seen there in over 50 years; bacterial genetic studies are being done at Harvard Medical School to help determine the source. Whatever the source, it is clear that Vibrio cholerae bacteria have arrived and spread widely as the organisms can now even be isolated from river water.

Because the bacteria cause an initial painless watery diarrhea (it appears to resemble "rice water" and smells fishy) and are present in diarrhea fluid often in large numbers, Vibrio strains help spread themselves into the environment. Many "fortunate" patients may have mild diarrhea (about 70%-80%) and not know they have cholera. Others have such aggressive diarrhea (250 ml/Kg fluid loss over 24 hours) that they develop nausea, vomiting, and stomach cramps. These patients quickly become dehydrated and so weak that the ill individuals soil themselves and their immediate surroundings and cannot clean up after themselves. Such patients, unless quickly treated with oral and IV fluids and frequently antibiotics, may die from dehydration (hypovolemic shock) and electrolyte abnormalities. Pregnant females, infants, and small children are more susceptible to severe illness than the general population. Children often appear sleepy and can lapse into a coma. In susceptible individuals, death can ensue in a matter of hours after symptoms appear. In some populations that have not experienced cholera in many years, untreated patients can have a 50% death rate.