Cholera occurs both sporadically and in large, abrupt epidemics.
Risk An epidemic of cholera started in South America in 1991, and has swept through Central and South America since then. Cholera cases were first recognized in Peru in the last week of January 1991. The majority of cases have been reported from Peru, Ecuador, Colombia, Guatemala, and Mexico. Cholera has been reported in coastal cities and inland areas of most of these countries. Cholera has also been reported in Cuzco in Peru and in the Galapagos Islands of Ecuador.