Summaryobjectives To evaluate the effectiveness of point of use water treatment with flocculent-disinfectant on reducing diarrhoea and the additional benefit of promoting hand washing with soap.methods The study was conducted in squatter settlements of Karachi, Pakistan, where diarrhoea is a leading cause of childhood death. Interventions were randomly assigned to 47 neighbourhoods. 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. Field workers visited households at least once a week from April to December 2003 to promote use of the interventions and to collect data on diarrhoea.results 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% (95% CI 17%, 80%) lower in bleach and water vessel neighbourhoods, 51% (95% CI 12%, 76%) lower in hand washing promotion with soap neighbourhoods, 64% lower (95% CI 29%, 90%) in disinfectant-disinfectant neighbourhoods, and 55% (95% CI 18%, 80%) lower in disinfectantdisinfectant plus hand washing with soap neighbourhoods.conclusions With an intense community-based intervention and supplies provided free of cost, each of the home-based interventions significantly reduced diarrhoea. There was no benefit by combining hand washing promotion with water treatment.

We conducted a study to determine if use of a new flocculant-disinfectant home water treatment reduced diarrhea. We randomly assigned 492 rural Guatemalan households to five different water treatment groups: flocculantdisinfectant, flocculant-disinfectant plus a customized vessel, bleach, bleach plus a vessel, and control. During one year of observation, residents of control households had 4.31 episodes of diarrhea per 100 person-weeks, whereas the incidence of diarrhea was 24% lower among residents of households receiving flocculant-disinfectant, 29% lower among those receiving flocculant-disinfectant plus vessel, 25% lower among those receiving bleach, and 12% lower among households receiving bleach plus vessel. In unannounced evaluations of home drinking water, free chlorine was detected in samples from 27% of flocculant-disinfectant households, 35% of flocculant-disinfectant plus vessel households, 35% of bleach households, and 43% of bleach plus vessel households. In a setting where diarrhea was a leading cause of death, intermittent use of home water treatment with flocculant-disinfectant decreased the incidence of diarrhea.

Objective To compare the effect on prevalence of diarrhoea and mortality of household based treatment of drinking water with flocculant-disinfectant, sodium hypochlorite, and standard practices in areas with turbid water source in Africa. Design Cluster randomised controlled trial over 20 weeks. Setting Family compounds, each containing several houses, in rural western Kenya. Participants 6650 people in 605 family compounds. Intervention Water treatment: flocculant-disinfectant, sodium hypochlorite, and usual practice (control). Main outcome measures Prevalence of diarrhoea and all cause mortality. Escherichia coli concentration, free residual chlorine concentration, and turbidity in household drinking water as surrogates for effectiveness of water treatment. Results In children < 2 years old, compared with those in the control compounds, the absolute difference in prevalence of diarrhoea was − 25% in the flocculant-disinfectant arm (95% confidence interval − 40 to − 5) and − 17% in the sodium hypochlorite arm ( − 34 to 4). In all age groups compared with control, the absolute difference in prevalence was − 19% in the flocculant-disinfectant arm ( − 34 to − 2) and − 26% in the sodium hypochlorite arm ( − 39 to − 9). There were significantly fewer deaths in the intervention compounds than in the control compounds (relative risk of death 0.58, P = 0.036). Fourteen per cent of water samples from control compounds had E coli concentrations < 1 CFU/100 ml compared with 82% in flocculant-disinfectant and 78% in sodium hypochlorite compounds. The mean turbidity of drinking water was 8 nephelometric turbidity units (NTU) in flocculant-disinfectant households, compared with 55 NTU in the two other compounds (P < 0.001). Conclusions In areas of turbid water, flocculant-disinfectant was associated with a significant reduction in diarrhoea among children < 2 years. This health benefit, combined with a significant reduction in turbidity, suggests that the flocculant-disinfectant is well suited to areas with highly contaminated and turbid water.

In an earlier study in rural Guatemala, 257 households that received flocculant-disinfectant to treat their drinking water had 39% less diarrhea than 257 control households. Three weeks after completion of the study, national marketing of the flocculant-disinfectant was extended into the study communities. Six months later, we assessed frequency of and characteristics associated with purchase and use of the flocculant-disinfectant by revisiting the original study households and administering a questionnaire. Four hundred sixty-two households (90%) completed the follow-up survey; 22 households (5%) purchased the flocculant-disinfectant within the preceding 2 weeks and used it within the last week. Neither being randomized to the intervention group during the efficacy study nor combined spending on laundry soap, toothpaste, and hand soap in the preceding week was associated with active repeat use. Even after efficacy was demonstrated within their community and an aggressive sophisticated marketing approach, few households purchased flocculant-disinfectant for point-of-use water treatment.

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