General Information: This is an epidemic serogroup of Vibrio cholerae isolated in 1971 in Bangladesh and is distinguished from the classical biotype due to hemolysin production. This genus is abundant in marine or freshwater environments such as estuaries, brackish ponds, or coastal areas; regions that provide an important reservoir for the organism in between outbreaks of the disease. Vibrio can affect shellfish, finfish, and other marine animals and a number of species are pathogenic for humans. Vibrio cholerae can colonize the mucosal surface of the small intestines of humans where it will cause cholera, a severe and sudden onset diarrheal disease. One famous outbreak was traced to a contaminated well in London in 1854 by John Snow, and epidemics, which can occur with extreme rapidity, are often associated with conditions of poor sanitation. The disease has a high lethality if left untreated, and millions have died over the centuries. There have been seven major pandemics between 1817 and today. Six were attributed to the classical biotype, while the 7th, which started in 1961, is associated with the El Tor biotype.