Evaluating the Effect of Mass Drug Administration on Soil-Transmitted Helminth Infection Rates in Sentinel Schools in Ondo State, South West Nigeria

Periodic mass drug administration with albendazole or mebendazole is a globally recommended strategy for reducing soil-transmitted helminth infection intensity in school-age children, yet evidence on its post-treatment epidemiological impact in specific Nigerian states following multiple rounds of implementation remains limited. This study evaluates the effect of mass drug administration on soil-transmitted helminth infection rates in sentinel schools in Ondo State, South West Nigeria. A before-and-after analytical design was employed, using pre-treatment baseline data from 20 sentinel schools in Akure South, Owo, and Odigbo Local Government Areas. Stool samples were collected from 500 children before treatment and at three months and 12 months post-treatment. The Kato-Katz technique was used for egg count quantification, and prevalence and intensity data were compared across time points using paired statistical tests. Covariates including WASH infrastructure, teacher deworming, and community sanitation were measured and controlled. Recent WHO monitoring data from 2020 to 2024 confirm that while albendazole reduces A. lumbricoides infection prevalence rapidly, reinfection rates in high-transmission environments frequently restore pre-treatment levels within six to twelve months without concurrent WASH improvements. This study provides empirical evidence for refining treatment interval recommendations in Ondo State and advocates for the integration of water and sanitation investments alongside periodic deworming. Findings will be submitted to the Ondo State NTD Programme and the WHO NTD department. Keywords: mass drug administration, soil-transmitted helminths, sentinel schools, Ondo State, reinfection.