Interventions to improve water quality are generally effective in preventing diarrhoea, and interventions to improve water quality at the household level are more effective than those at the source. Significant heterogeneity among the trials suggests that the actual level of effectiveness may depend on a variety of conditions that research to date cannot fully explain. Rigorous, blinded, multi-arm randomized controlled trials conducted over a longer duration in a variety if settings may help clarify the potential effectiveness.
Impact of chlorination of water in domestic storage tanks on childhood diarrhoea: a community trial in the rural areas of Saudi Arabia.
During the period September 1991 to February 1992 standard chlorination packages of calcium hypochloride were provided for the first time to 171 families residing in the catchment area of the Sabt-Bany Bishr Primary Health Care Centre in the rural areas of the Asir region, south-western Saudi Arabia. The villagers added the packages to their home storage water tanks each time they added water from the 220 nearby wells. Analysis of the water samples taken from these wells showed that all of them were bacteriologically unfit for human use. By the end of the study period there were no bacteriologically unfit water samples taken from the tanks of the participating families. Children under 5 years of age whose families were not using chlorinated water had twice the risk of diarrhoea compared to children from the participating families (odds ratio = 1.98, P = 0.047). The use of chlorinated water was associated with a 48% reduction in diarrhoea. These results indicate that the chlorination of water can be successfully carried out locally in rural areas to improve the health of the population.