Household-based water treatment for the prevention of diarrhoeal disease
Unsafe drinking water, together with poor hygiene and sanitation, are the main contributors to diarrhoeal disease, a leading cause of mortality and morbidity especially among young children in low-income settings. While the Millennium Development Goals seek to halve the portion of the population without access to safe water by 2015, the high cost of piped-in supplies has led the World Health Organization to call for alternative approaches, including household water treatment. This thesis describes the results of certain research concerning the effectiveness, cost-effectiveness and field implementation of household water treatment for the prevention of diarrhoeal disease. In a systematic review of interventions to improve water quality for the prevention of endemic diarrhoea, 30 studies covering 38 intervention trials were identified and meta- analyzed. The studies varied considerably in design, setting, type of intervention and point of intervention. The evidence suggests that in settings with sufficient water quantity, interventions to improve the microbiological quality of drinking water are effective in preventing diarrhoea, and that household-based interventions are about twice as effective as conventional improvements at the water source. The costs of such water quality interventions was compiled and combined with the effectiveness data from the systematic review to determine the cost-effectiveness of interventions to improve water quality. In most settings, household water treatment meets established criteria for "highly cost effective" health interventions. In a six-month pilot programme in Colombia, household-based water filters were associated with a substantial improvement in microbial water quality and a 60% reduction in the prevalence of diarrhoea (OR = 0.40,95% CI = 0.25,0.63, P<0.0001). In a study to assess the drinking water response to the Indian Ocean tsunami, household water treatment had only a limited role, suggesting the need to consider under what circumstances such interventions can contribute to the delivery of safe drinking water in the immediate aftermath of an emergency. The thesis concludes with some thoughts on the challenge of implementing household water treatment and the need for further research.