A bacterium called Vibrio cholerae Serogroup O1 or Vibrio cholerae Serogroup non-O1 is what causes cholera. In most cases, Vibrio cholerae Serogroup O1 is responsible for the disease. Cholera is usually transmitted by eating food or drinking water that is contaminated with either bacteria. In the United States, most infections have occurred due to contaminated shellfish.
There are two general types of Vibrio cholerae:
- Vibrio cholerae Serogroup non-O1 (the most common cause)
- Vibrio cholerae Serogroup O1.
Vibrio cholerae is native to the Ganges delta, which is in India and extends into Bangladesh. Since 1995, more than 80 percent of reported cases of Vibrio cholerae infections have occurred in Africa.
Vibrio cholerae infections have been rare in industrialized nations for the last 100 years. For example, in the United States, there are zero to five cases per year. In the United States, most Vibrio cholerae infections have occurred in Louisiana and the Gulf of Mexico, due to contaminated shellfish.
Cholera is usually transmitted by drinking water or eating food that is contaminated with Vibrio cholerae.
There are two ways that the bacteria usually gets into food or water:
- Contaminated feces.
Since cholera is not likely to spread directly from one person to another, casual contact with an infected person is not a risk for becoming ill.