Unsafe drinking water, inadequate availability of water for hygiene and lack of access to sanitation together contribute to about 88 per cent of deaths from diarrhoeal diseases, or more than 1.5 million of the 1.9 million children under five who perish from diarrhoea each year. This amounts to 18 per cent of all under-five deaths and means that more than 5,000 children are dying every day as a result of diarrhoeal diseases.
Diarrhoea’s impact is particularly severe in children. Acute diarrhoea, as occurs with cholera, if left untreated can cause death within a day or less.
Diarrhoeal diseases are transmitted through human excreta, and it is therefore critically important to have effective barriers in place to prevent this major transmission route. Improved sanitation alone could reduce diarrhoea-related morbidity by more than a third; improved sanitation combined with hygiene awareness and behaviours could reduce it by two thirds. Such behaviours include consistent use of a toilet or latrine by each person in the household, safe disposal of young children’s faeces and hand washing with soap or ash after defecation and before eating.
Undernutrition, which is associated with more than half of all under-five deaths, is closely linked to diarrhoea. Infectious diseases, and diarrhoea in particular, are the main determinants of wasting and stunting of growth in children in developing countries.
Low child mortality and high levels of water and sanitation provision are connected. Historical analysis of how diarrhoea mortality was virtually eradicated in Stockholm (Sweden) in the period up to 1925 suggests that, along with public education and the enforcement of sanitary laws and regulations, large-scale interventions expanding access to clean water had the greatest impact when implemented as part of a broader package that included improved sanitation.