The bacterium Vibrio cholerae causes cholera. Although two hundred different types exist, only two cause disease in humans. These cause epidemics with a characteristic, severe diarrhea. This diarrhea is caused by the toxin cholera toxin, which the bacteria excrete.
In most people, cholera is usually mild and also goes away on its own. In these cases, the clinical picture resembles that of other pathogens that cause diarrhea.
The typical clinical picture of cholera is sudden vomiting and large amounts of water-thin diarrhea. This resembles "rice water," is pale yellow-green in color with flakes and has almost no odor.
Cholera patients do not have abdominal cramps, but may have a nagging abdominal pain or pressure sore. The biggest danger with cholera is dehydration, because patients lose a lot of fluids. This can be as much as one liter per hour. Treatment consists of recovering the fluid loss.
People get sick from eating or drinking contaminated foods. Extra at risk are seafood. The bacteria attach to plankton, which then end up in seafood. The bacteria accumulate in them. Contact with, or consumption of, these foods can therefore cause infection. The feces itself is also a source of infection.
The bacteria are found in brackish surface water. Vibrio cholerae occurs worldwide, but the two types that cause epidemics are mainly found in South Asia, Africa, South America and the Gulf of Mexico.
In 2007, the WHO(World Health Organization) reported cholera in 53 countries, with more than 177,000 cases. WHO estimates that only 5 to 10% of cholera cases are reported. More than 90% of cases occur in Africa.