Featured Review: Interventions to improve water quality for preventing diarrhoea
Interventions at point-of-use important interim measures to improve drinking water quality
Contaminated water is a major cause of diarrhoea worldwide, especially among young children in low- and middle-income countries. In these settings, water often has to be collected from open rivers or streams, sometimes carried long distances, and frequently stored in open containers. As a protective measure, water may be treated at the point-of-use in people's homes by boiling, chlorination, flocculation, filtration, or solar disinfection. These point-of-use interventions have the potential to overcome both contaminated sources and recontamination of safe water in the home.
A team of Cochrane authors based in Kenya, the United Kingdom, and the United States worked with Cochrane Infectious Diseases to determine the effectiveness of interventions to improve water quality for preventing diarrhoea. The researchers included 55 studies, which included 84,000 participants, in this review.
While reliable, piped-in supplies of clean water are undoubtedly the preferred option, the review authors found no trials assessing this, and only very few trials assessing improvements in the water source such as wells, bore holes, or harvested rain water.
However, the review authors included 47 trials, enrolling more than 72,000 participants, assessing interventions to improve the quality of drinking water in peoples’ homes. “These interventions that address the microbial contamination of water at the point-of-use can be important interim measures to improve drinking water quality,” said Professor Thomas Clasen from Emory University, the lead author of the review, “especially as re-contamination often occurs during use in the home, even where the source water is relatively safe”.
The review authors found that interventions of distributing chlorine products or sachets of disinfectant to people’s homes, to be added to stored water, may reduce diarrhoea episodes by about 25%, and that water filtration at home using various types of filtration systems probably reduces diarrhoea rates by around 50%. They also found some evidence that even very low-tech solutions, such as leaving bottled water in direct sunlight for six hours, may have important protective effects.
“The evidence suggests that the more people use these interventions, the greater the benefits,” added Professor Clasen, “so we also need research into practical approaches to increase the coverage and consistent, long-term use of these interventions, particularly among the most vulnerable populations”.