The Relationship between Water, Sanitation and Schistosomiasis: A Systematic Review and Meta-analysis

• Type of Material: Article
• Authors: Jack E. T. Grimes, Imperial College London; David Croll, Swiss Tropical and Public Health Institute; Wendy E. Harrison, Imperial College London; Jürg Utzinger, Swiss Tropical and Public Health Institute; Matthew Freeman, Emory University; Michael R. Templeton, Imperial College London
• Language: English
• Date: 2014-12-04
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: © 2014 Grimes et al.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pntd.0003296
• Title of Journal or Parent Work: PLoS Neglected Tropical Diseases
• ISSN: 1935-2727
• Volume: 8
• Issue: 12
• Start Page: e3296
• End Page: e3296
• Grant/Funding Information: JETG, WEH and MRT were supported with unrestricted funds through Imperial College London.; MCF was funded in part by UK Aid from the Department for International Development (DFID) as part of the SHARE Research Programme (www.SHAREResearch.org).
• Keywords: Schistosomiasis; REPUBLIC-OF-CHINA; Schistosoma; RISK-FACTORS; Parasitology; Science & Technology; Infectious Diseases; Meta-analysis; MINAS-GERAIS; Sanitation; Schistosoma haematobium; SCHOOL-CHILDREN; SOCIODEMOGRAPHIC CHARACTERISTICS; Schistosoma japonicum; NEGLECTED TROPICAL DISEASES; Water resources; INTESTINAL PARASITOSIS; MANSONI INFECTION; SOIL-TRANSMITTED HELMINTH; CONTACT PATTERNS; Life Sciences & Biomedicine; Schistosoma mansoni; Tropical Medicine
• Research Categories: Health Sciences, Public Health; Health Sciences, Epidemiology

Abstract

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. 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. 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. 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.