ISSN 2756-3391
African Journal of Parasitology Research | Vol. 14, No. 8, August 2026 | pp. 749–756
DOI: 10.46882/AJPR/140749
Article Type: Full Length Research Paper
Title: Spatio-temporal distribution and genetic validation of intermediate snail hosts of Schistosoma haematobium in riverine ecosystems of Southern Province, Sierra Leone
Names of Authors: Sahr P. Mattia¹, Findabag J. Sesay¹, Alhassan K. Bangura²
Authors’ Affiliations: ¹Department of Biological Sciences, School of Environmental Sciences, Njala University, Njala, Sierra Leone. ²Ministry of Health and Sanitation, Vector-Borne Disease Control Program, Freetown, Sierra Leone.
Abstract: Changes in local river ecosystems are major drivers of urogenital schistosomiasis transmission in rural West Africa. This longitudinal investigation mapped the macro-spatial distribution, ecological preferences, and larval infection rates of intermediate snail hosts across 35 riverine communities in southern Sierra Leone. A total of 1540 freshwater snails were harvested over a 12-month period, and species identity was verified by sequencing the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. Bulinus globosus was identified as the main vector, accounting for 72.4 percent of the collected snails, followed by Bulinus forskalii (27.6 percent). Molecular screening discovered active Schistosoma haematobium cercarial shedding in 5.2 percent of the Bulinus globosus population. Microgeographic mapping linked high snail densities to slow-flowing river banks with high clear-water penetration and low human pollution. Multivariate logistic regression associated high snail presence with water temperatures between 24.5 and 27.0 degrees Celsius (odds ratio = 3.12, 95 percent confidence interval [1.68 to 5.84]) and dense overhanging canopy cover (odds ratio = 2.45, 95 percent confidence interval [1.22 to 4.97]). DNA sequencing of the larval stages confirmed 99.8 percent identity with human Schistosoma haematobium strains from West Africa. These findings map the exact ecological niches sustaining endemic urogenital schistosomiasis, providing key data for targeted environmental snail controls.
Keywords: Schistosoma haematobium, Bulinus globosus, Intermediate hosts, Riverine ecology, Microgeographic mapping, Sierra Leone
Manuscript Timeline: Received: 18 June 2026; Revised: 14 July 2026; Accepted: 08 August 2026; Published: 24 August 2026
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