Water, sanitation, hygiene and enteric infections in children. Arch Dis Child doi:10.1136/archdischild-2011-301528
Joe Brown, Sandy Cairncross, Jeroen H J Ensink
Correspondence info: Dr Jeroen H J Ensink, Environmental Health Group, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; Jeroen.firstname.lastname@example.org
In this article, we review the evidence linking WSH measures to faecal-oral diseases in children. Although continued research is needed, existing evidence from the last 150 years supports extending life-saving WSH measures to at-risk populations worldwide. One recent estimate held that 95% of diarrhoeal deaths in children under 5 years of age could be prevented by 2025, at a cost of US$6.715 billion, through targeted scale-up of proven, cost-effective, life-saving interventions. These include access to safe and accessible excreta disposal, support for basic hygiene practices such as hand washing with soap, and provision of a safe and reliable water supply. We present estimates of the burden of WSH-related disease followed by brief overviews of water, sanitation and hygiene-related transmission routes and control measures. We conclude with a summary of current international targets and progress.
Diarrhoea, malnutrition and environmental enteropathy
Although great strides have been made in reducing diarrhoea mortality, especially as a result of the increased use of oral rehydration therapy (ORT), diarrhoea remains the second leading cause of death in children under 5 years of age, after pneumonia. It is responsible for an estimated 1.7 billion cases of diarrhoea, or on average 2.9 episodes/child/year, and an estimated 1.87 million deaths among children under 5 years of age.The highest burden of disease is in children in the age range of 6–11 months: 4.5 episodes/child/year. It has been estimated that 50% of diarrhoea deaths can be attributed to persistent diarrhoea,7 and while ORT can prevent many deaths from acute diarrhoeal diseases,8 access to appropriate treatment is often limited in resource-poor settings.
The relationship between diarrhoeal disease and malnutrition is complex, though it is well accepted that malnourished children suffer more frequent episodes of diarrhoeal disease, while a child’s nutritional status is affected following a diarrhoeal episode. A multiple country study found that 25% of stunting in children aged 24 months could be attributable to five or more diarrhoeal episodes experienced in the first 2 years of life. Malnutrition and stunting can lead to poorer school performance, early school drop-out and, as a result, lower economic well-being in later life. Over 440 million school days are missed annually due to WSH-related illnesses. Extended exposure to faecal pathogens may, in part, cause environmental enteropathy, a postulated condition characterised by malabsorption, villus atrophy, crypt hyperplasia, T-cell infiltration and general inflammation of the jejunum. This chronic infection of the small intestine could explain why sanitation may have a stronger association with gains in growth than with reductions in diarrhoea incidence.