Interventions to improve water quality for preventing diarrhoea

Area of Science:

• Public Health
• Environmental Health
• Infectious Disease Prevention

Background:

• Diarrhoea is a leading cause of mortality, particularly in young children in low-income countries, often spread through fecal-contaminated water.
• Water quality interventions include source-based improvements (protected groundwater, rainwater) and point-of-use (POU) treatments (boiling, chlorination, filtration, solar disinfection).

Purpose of the Study:

• To evaluate the effectiveness of various water quality improvement interventions in preventing diarrhoea.

Main Methods:

• Systematic review and meta-analysis of randomized controlled trials (RCTs), quasi-RCTs, and controlled before-and-after studies.
• Searched multiple databases (Cochrane, MEDLINE, EMBASE, LILACS) and included studies up to November 2014.
• Assessed trial quality and extracted data, using meta-analyses and subgroup analyses to determine effect sizes and heterogeneity.

Main Results:

• Source-based water improvements showed insufficient evidence for consistent diarrhoea reduction.
• POU disinfection products (chlorination, flocculation sachets) reduced diarrhoea by approximately 25% (low to moderate quality evidence).
• POU filtration systems (ceramic, biosand, LifeStraw®) demonstrated significant reductions, halving diarrhoea episodes (moderate quality evidence).
• Solar water disinfection (SODIS) likely reduced diarrhoea by about one-third (moderate quality evidence).

Conclusions:

• POU water interventions are effective interim measures for improving drinking water quality and reducing diarrhoea.
• No single POU intervention demonstrated superiority; effectiveness is influenced by adherence and safe storage.
• Further research on household water connections and programmatic approaches to optimize POU intervention utilization is recommended.