title: The relationship between water, sanitation and schistosomiasis: a systematic review and meta-analysis.
abstract: BACKGROUND
  Access to "safe" water and "adequate" sanitation are emphasized as important measures for schistosomiasis control. Indeed, the schistosomes' lifecycles suggest that their transmission may be reduced through safe water and adequate sanitation. However, the evidence has not previously been compiled in a systematic review.
  
  
  METHODS
  We carried out a systematic review and meta-analysis of studies reporting schistosome infection rates in people who do or do not have access to safe water and adequate sanitation. PubMed, Web of Science, Embase, and the Cochrane Library were searched from inception to 31 December 2013, without restrictions on year of publication or language. Studies' titles and abstracts were screened by two independent assessors. Papers deemed of interest were read in full and appropriate studies included in the meta-analysis. Publication bias was assessed through the visual inspection of funnel plots and through Egger's test. Heterogeneity of datasets within the meta-analysis was quantified using Higgins' I2.
  
  
  RESULTS
  Safe water supplies were associated with significantly lower odds of schistosomiasis (odds ratio (OR) = 0.53, 95% confidence interval (CI): 0.47-0.61). Adequate sanitation was associated with lower odds of Schistosoma mansoni, (OR = 0.59, 95% CI: 0.47-0.73) and Schistosoma haematobium (OR = 0.69, 95% CI: 0.57-0.84). Included studies were mainly cross-sectional and quality was largely poor.
  
  
  CONCLUSIONS
  Our systematic review and meta-analysis suggests that increasing access to safe water and adequate sanitation are important measures to reduce the odds of schistosome infection. However, most of the studies were observational and quality was poor. Hence, there is a pressing need for adequately powered cluster randomized trials comparing schistosome infection risk with access to safe water and adequate sanitation, more studies which rigorously define water and sanitation, and new research on the relationships between water, sanitation, hygiene, human behavior, and schistosome transmission.
authors.affiliation: Department of Civil and Environmental Engineering, Imperial College London, London, United Kingdom.
authors.forename: Jack E T
authors.initials: JE
authors.lastname: Grimes
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: David
authors.initials: D
authors.lastname: Croll
authors.affiliation: Schistosomiasis Control Initiative, Imperial College London, London, United Kingdom.
authors.forename: Wendy E
authors.initials: WE
authors.lastname: Harrison
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
authors.affiliation: Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Freeman
authors.affiliation: Department of Civil and Environmental Engineering, Imperial College London, London, United Kingdom.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Templeton
mesh_terms: D003430:Cross-Sectional Studies; D006801:Humans; D012499:Sanitation / Q000706:statistics & numerical data*; D012552:Schistosomiasis / Q000453:epidemiology*; D060753:Water Quality; D014881:Water Supply / Q000592:standards / Q000706:statistics & numerical data*