Combining drinking water treatment and hand washing for diarrhoea prevention, a cluster randomised controlled trial.

The study was conducted in squatter settlements of Karachi, Pakistan. Households in 10 neighbourhoods received diluted bleach and a water vessel; nine neighbourhoods received soap and were encouraged to wash hands; nine neighbourhoods received flocculent-disinfectant water treatment and a water vessel; 10 neighbourhoods received disinfectant-disinfectant water treatment and soap and were encouraged to wash hands; and nine neighbourhoods were followed as controls. Study participants in control neighbourhoods had diarrhoea on 5.2% of days. Compared to controls, participants living in intervention neighbourhoods had a lower prevalence of diarrhoea: 55% lower in bleach and water vessel neighbourhoods, 51% lower in hand washing promotion with soap neighbourhoods, 64% lower in disinfectant-disinfectant neighbourhoods, and 55% lower in disinfectant-disinfectant plus hand washing with soap neighbourhoods. Although each of the home-based interventions significantly reduced diarrhoea, there was no benefit by combining hand washing promotion with water treatment. Tropical Medicine & International Health 2006;11:479-89.