Water, Sanitation and Hygiene for the Prevention of Diarrhoea

This journal paper by Cairncross et al. (2013), published in the International Journal of Epidemiology presents the findings of a study which drew on three systematic reviews focussed on the effect of handwashing with soap, water quality improvement and excreta disposal on diarrhoea, to estimate their respective effect on diarrhoea mortality. In addition to highlighting the stricking effect of handwashing with soap (that was found to be consistent across various study designs and pathogens), the study found a similarly large effect of water treatment (though not in blinded studies, suggesting that it may be partly due to the placebo effect), and very little rigorous evidence for the health benefit of sanitation. The authors conclude by proposing diarrhoea risk reductions of 48, 17 and 36%, associated respectively, with handwashing with soap, improved water quality and excreta disposal as the estimates of effect for the LiST model. They emphasise that most of the evidence is of poor quality and that more trials are needed. Nonetheless, the evidence remains nonetheless strong enough to support WASH for all.