The true burden and risk of cholera: implications for prevention and control.

Cholera is a substantial health burden on the developing world. The exact scale of the problem is uncertain because of limitations in existing surveillance systems, differences in reporting procedures, and failure to report cholera to WHO; official figures are likely to greatly underestimate the true prevalence of the disease. We have identified, through extensive literature searches, additional outbreaks of cholera to those reported to WHO, many of which originated from the Indian subcontinent and southeast Asia. The Lancet Infectious Diseases 2007;7:521-30.