title: Solar drinking water disinfection (SODIS) to reduce childhood diarrhoea in rural Bolivia: a cluster-randomized, controlled trial.
abstract: BACKGROUND
  Solar drinking water disinfection (SODIS) is a low-cost, point-of-use water purification method that has been disseminated globally. Laboratory studies suggest that SODIS is highly efficacious in inactivating waterborne pathogens. Previous field studies provided limited evidence for its effectiveness in reducing diarrhoea.
  
  
  RESULTS
  We conducted a cluster-randomized controlled trial in 22 rural communities in Bolivia to evaluate the effect of SODIS in reducing diarrhoea among children under the age of 5 y. A local nongovernmental organisation conducted a standardised interactive SODIS-promotion campaign in 11 communities targeting households, communities, and primary schools. Mothers completed a daily child health diary for 1 y. Within the intervention arm 225 households (376 children) were trained to expose water-filled polyethyleneteraphtalate bottles to sunlight. Eleven communities (200 households, 349 children) served as a control. We recorded 166,971 person-days of observation during the trial representing 79.9% and 78.9% of the total possible person-days of child observation in intervention and control arms, respectively. Mean compliance with SODIS was 32.1%. The reported incidence rate of gastrointestinal illness in children in the intervention arm was 3.6 compared to 4.3 episodes/year at risk in the control arm. The relative rate of diarrhoea adjusted for intracluster correlation was 0.81 (95% confidence interval 0.59-1.12). The median length of diarrhoea was 3 d in both groups.
  
  
  CONCLUSIONS
  Despite an extensive SODIS promotion campaign we found only moderate compliance with the intervention and no strong evidence for a substantive reduction in diarrhoea among children. These results suggest that there is a need for better evidence of how the well-established laboratory efficacy of this home-based water treatment method translates into field effectiveness under various cultural settings and intervention intensities. Further global promotion of SODIS for general use should be undertaken with care until such evidence is available.
  
  
  BACKGROUND
  www.ClinicalTrials.govNCT00731497 Please see later in the article for Editors' Summary.
authors.affiliation: Department of Public Health and Epidemiology, Swiss Tropical Institute (STI), University of Basel, Switzerland. Daniel.Maeusezahl@unibas.ch
authors.forename: Daniel
authors.initials: D
authors.lastname: Mäusezahl
authors.forename: Andri
authors.initials: A
authors.lastname: Christen
authors.forename: Gonzalo Duran
authors.initials: GD
authors.lastname: Pacheco
authors.forename: Fidel Alvarez
authors.initials: FA
authors.lastname: Tellez
authors.forename: Mercedes
authors.initials: M
authors.lastname: Iriarte
authors.forename: Maria E
authors.initials: ME
authors.lastname: Zapata
authors.forename: Myriam
authors.initials: M
authors.lastname: Cevallos
authors.forename: Jan
authors.initials: J
authors.lastname: Hattendorf
authors.forename: Monica Daigl
authors.initials: MD
authors.lastname: Cattaneo
authors.forename: Benjamin
authors.initials: B
authors.lastname: Arnold
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Smith
authors.forename: John M
authors.initials: JM
authors.lastname: Colford
mesh_terms: D001838:Bolivia / Q000453:epidemiology; D002675:Child, Preschool; D016000:Cluster Analysis; D003906:Developing Countries; D003967:Diarrhea / Q000453:epidemiology / Q000517:prevention & control*; D004203:Disinfection / Q000379:methods*; D005260:Female; D005767:Gastrointestinal Diseases / Q000453:epidemiology*; D006293:Health Promotion; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007223:Infant; D010349:Patient Compliance; D012423:Rural Health; D013472:Sunlight; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*; D014881:Water Supply
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