title: Effect of sanitation and water treatment on intestinal protozoa infection: a systematic review and meta-analysis.
abstract: BACKGROUND
  Pathogenic intestinal protozoa infections are responsible for substantial mortality and morbidity, particularly in settings where people lack improved sanitation and safe drinking water. We assessed the relation between access to, and use of, sanitation facilities and water treatment and infection with intestinal protozoa.
  
  
  METHODS
  We did a systematic review and searched PubMed, ISI Web of Science, and Embase from inception to June 30, 2014, without restrictions on language. All publications were examined by two independent reviewers and were included if they presented data at the individual level about access or use of sanitation facilities or water treatment, in combination with individual-level data on human intestinal protozoa infections. Meta-analyses using random effects models were used to calculate overall estimates.
  
  
  RESULTS
  54 studies were included and odds ratios (ORs) extracted or calculated from 2 × 2 contingency tables. The availability or use of sanitation facilities was associated with significantly lower odds of infection with Entamoeba histolytica or Entamoeba dispar (OR 0·56, 95% CI 0·42-0·74) and Giardia intestinalis (0·64, 0·51-0·81), but not for Blastocystis hominis (1·03, 0·87-1·23), and Cryptosporidium spp (0·68, 0·17-2·68). Water treatment was associated with significantly lower odds of B hominis (0·52, 0·34-0·78), E histolytica or E dispar (0·61, 0·38-0·99), G intestinalis (0·63, 0·50-0·80), and Cryptosporidium spp infections (0·83, 0·70-0·98).
  
  
  CONCLUSIONS
  Availability and use of sanitation facilities and water treatment is associated with lower odds of intestinal protozoa infections. Interventions that focus on water and sanitation, coupled with hygiene behaviour, should be emphasised to sustain the control of intestinal protozoa infections.
  
  
  BACKGROUND
  Swiss National Science Foundation (project numbers PBBSP3-146869 and P300P3-154634), Medicor Foundation, European Research Council (614739-A_HERO).
authors.affiliation: Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Speich
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland.
authors.forename: David
authors.initials: D
authors.lastname: Croll
authors.affiliation: Centre for Health Policy and Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Fürst
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
authors.affiliation: Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland. Electronic address: jennifer.keiser@unibas.ch.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Keiser
mesh_terms: D006801:Humans; D007411:Intestinal Diseases, Parasitic / Q000517:prevention & control*; D016017:Odds Ratio; D011528:Protozoan Infections / Q000517:prevention & control*; D012307:Risk Factors; D012499:Sanitation; D018508:Water Purification / Q000379:methods*