In the accompanying paper, Roy and colleagues report that zinc supplementation has an additional benefit over antimicrobial treatments in reducing the duration and severity of cholera in children.1 The study was carried out in Bangladesh, where cholera is endemic.

Cholera is a common disease in many countries of the world. About 230 000 cases in more than 50 countries are reported globally, but the World Health Organization estimates that official notifications make up only 5-10% of the real burden of cholera.2 This means that as many as three million cases and more than 100 000 deaths occur each year.2 3

Cholera may be undetected for various reasons. About 80-90% of episodes are of mild to moderate severity. Therefore, without performing routine culture for Vibrio cholerae, the infection is difficult to distinguish clinically from other causes of acute diarrhoea, including traveller’s diarrhoea. Also, until recently economic repercussions such as restrictions to food exports and losses to tourism have acted as strong disincentives for reporting.2 3 …