Cholera and genetics.

DEFINITION Cholera is an infection of the small intestine caused by the comma-shaped bacterium Vibrio cholerae. Cholera arose centuries ago in India and was disseminated throughout Asia and Europe by trade and pilgrimage. It was devastating, causing epidemics that resulted in countless deaths. By the early twentieth century, cholera had been confined mostly to Asia. In 1961, however, a cholera pandemic beginning in Indonesia spread to Africa, the Mediterranean nations, and North America. Because cholera has a 50 to 60 percent fatality rate when its symptoms are not treated quickly, occasional cases cannot be ignored; both the consequences to afflicted people and the potential for the outbreak of epidemics are great.