Solar disinfection of water reduces diarrhoeal disease: an update

Abstract

349 Maasai children younger than 6 years old were randomised by alternate household to drink water either left in plastic bottles exposed to sunlight on the roof of the house or kept indoors (control). The trial was run in Maasai by Maasai community elders. Children drinking solar disinfected water had a significantly lower risk of severe diarrhoeal disease over 8705 two weekly follow up visits; two week period prevalence was 48.8% compared with 58.1% in controls, corresponding to an attributable fraction of 16.0%. While this reduction is modest, it was sustained over a year in free living children. It confirms solar disinfection as eVective in vivo as a free, low technology, point of consumption method of improving water quality. The continuing use of solar disinfection by the community underlines the value of community participation in research. (Arch Dis Child 1999;81:337-338)

Optimizing the solar water disinfection (SODIS) method by decreasing turbidity with NaCl

“…The effectiveness of the SODIS method at decreasing diarrheal incidence has also been investigated in epidemiological intervention studies and has proven to be credible: a decrease in diarrhea incidence by as much as 86% has been observed (Centre for Disease Control 2008; Graf et al 2010;Meierhofer 2006;World Health Organization 2002). The method has shown to be particularly effective at reducing diarrhea in children under the age of five (Conroy et al 1995;1999;Graf et al 2010;Rai et al 2010;Rose et al 2006).…”

Solar Drinking Water Disinfection (SODIS) to Reduce Childhood Diarrhoea in Rural Bolivia: A Cluster-Randomized, Controlled Trial

“…On the other hand, our result of a 19% reduction in diarrhoeal episodes appears to be roughly consistent with results of the two other SODIS trials both from Maasai cultural settings conducted by Conroy and colleagues among children ,6 y and 5-16 y of age. They report a 16% reduction (in ,6 y olds, 2-wk prevalence of 48.8% in intervention, and 58.1% in control group) [8] and a 10.3% reduction in the 2-wk diarrhoea prevalence (in 5-16 y olds) [7]. However, these randomized controlled trials were undertaken in a socio-cultural setting assuring a 100% compliance (as stated by the authors) in water treatment behaviour through social control by Maasai elders who promoted the method [7,8].…”

“…They report a 16% reduction (in ,6 y olds, 2-wk prevalence of 48.8% in intervention, and 58.1% in control group) [8] and a 10.3% reduction in the 2-wk diarrhoea prevalence (in 5-16 y olds) [7]. However, these randomized controlled trials were undertaken in a socio-cultural setting assuring a 100% compliance (as stated by the authors) in water treatment behaviour through social control by Maasai elders who promoted the method [7,8]. In the results presented in these studies adjusted models with post hoc selected covariates were presented (i.e., no unadjusted models were provided).…”

“…The three reported SODIS trials to date implemented the intervention at the household level, two of them in highly controlled settings that ensured very high compliance [7][8][9]. The highest reduction in incidence (36%) was recorded in a trial carried out among 200 children in an urban slum in Vellore, India [9].…”

Household Water Purification: Low-Cost Interventions

“…The SODIS system consists of four basic steps; removing solids from highly turbid (>30 NTU) water by settling or filtration, placing low turbidity (<30 NTU) water in clear plastic bottles, aerating the water by vigorous shaking in contact with air and exposing the filled, aerated bottles to full sunlight for about five hours or longer if only part sunlight. There was a measurable reduction in diarrheal disease and cholera in Kenyan children drinking solar disinfected water [10].…”