Land use impacts on parasitic infection: A cross-sectional epidemiological study on the role of irrigated agriculture in schistosome infection in a dammed landscape

Background: Water resources development promotes agricultural expansion and food security. But are these benefits offset by increased infectious disease risk? Dam construction on the Senegal River in 1986 was followed by agricultural expansion and increased transmission of human schistosomes. Yet the mechanisms linking these processes at the individual and household levels remain unclear. We investigated the association between household land use and schistosome infection in children. Methods: We analyzed cross-sectional household survey data (n = 655) collected in 16 rural villages in August 2016 across demographic, socio-economic and land use dimensions, which were matched to S. haematobium (n = 1232) and S. mansoni (n = 1222) infection data collected from school-aged children. Mixed effects regression determined the relationship between irrigated area and schistosome infection presence and intensity. Results: Controlling for socio-economic and demographic risk factors, irrigated area cultivated by a household was associated with an increase in the presence of S. haematobium infection (odds ratio [OR] = 1.14; 95% confidence interval [95% CI]: 1.03, 1.28) but not S. mansoni infection (OR = 1.02; 95% CI: 0.93, 1.11). Associations between infection intensity and irrigated area were positive but imprecise (S. haematobium: rate ratio [RR] = 1.05; 95% CI: 0.98, 1.13, S. mansoni: RR = 1.09; 95% CI: 0.89, 1.32). Conclusion: Household engagement in irrigated agriculture increases individual risk of S. haematobium but not S. mansoni infection. Increased contact with irrigated landscapes likely drives exposure, with greater impacts on households relying on agricultural livelihoods.Funding provided by: National Science FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000001Award Number: 1414102Funding provided by: Bill and Melinda Gates FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000865Award Number: OPP1114050Funding provided by: National Institutes of HealthCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000002Award Number: R01TW010286Funding provided by: Stanford UniversityCrossref Funder Registry ID: http://dx.doi.org/10.13039/100005492Award Number: James and Nancy Kelso Fellowship: Interdisciplinary Graduate FellowshipFunding provided by: Emmett Interdisciplinary Program in Environment and Resources*Crossref Funder Registry ID: Award Number: Davis Family E-IPER FellowshipFunding provided by: Emmett Interdisciplinary Program in Environment and ResourcesCrossref Funder Registry ID: Award Number: Davis Family E-IPER Fellowshi