Diarrhoea counts for 1.8 million deaths in children in low- and middle-income countrie (LMICs). One of the identified strategies to prevent diarrhoea is hand washing. This reduces the incidence of diarrhoea by about 30% in child day-care centres in high-income countries and in communities in low- and middle-income countries.

This 'hand washing promotion for preventing diarrhoea' review has recently been updated and is available in Issue 9, 2015 of the Cochrane Database of Systematic Reviews: 

http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD004265.pub3/abstract