Molecular Characterization and transmission indices of malaria vector in a rural community in Osun State south-west Nigeria.

UNLABELLED: Sustained malaria transmission in rural sub-Saharan Africa continue to pose a global public health menace with community-level molecular entomological data still limited in south-western Nigeria despite persistent endemicity. This study evaluated mosquito species composition, sibling species structure, blood meal sources, and infectivity in a rural community in Osun State, Nigeria. Adult mosquitoes were collected monthly between February and July 2024 from randomly selected households in Omun-Owode, Osogbo, using pyrethrum spray catch (PSC) and Centre for Disease Control and Prevention (CDC) light traps. Morphological identification was performed using standard taxonomic keys. Anopheles gambiae sensu lato was subjected to polymerase chain reaction (PCR) for sibling species identification, host blood meal analysis, and detection of sporozoite infectivity. Variation in mosquito abundance across methods and months were analyzed using Analysis of Variance (ANOVA) with a p-value of less than 0.05 as a threshold of statistical significance in variation at 95% confidence interval (CI). A total of 242 female mosquitoes comprising four species were collected: Culex quinquefasciatus (55.8%), Anopheles gambiae s.l. (32.6%), Mansonia uniformis (10.7%), and Aedes aegypti (0.8%). PSC yielded higher overall collections than CDC light traps, though not statistically significant (p = 0.075). Seasonal variation showed increased Anopheles abundance during the rainy months, peaking in July (p = 0.09). Molecular analysis (n = 50) revealed predominance of Anopheles coluzzii (99%) over Anopheles gambiae s.s. (1%) (p < 0.001). Blood meal analysis demonstrated exclusive human feeding (100%; 95% CI: 92.9–100%), indicating strong anthropophagy. Plasmodium falciparum sporozoites were detected in 2% of analyzed specimens. The predominance of Anopheles coluzzii, high human blood index, and detectable sporozoite infection confirm ongoing falciparum malaria transmission in the study area, albeit at relatively low infectivity levels. Sustained molecular surveillance and integrated vector control strategies are required to prevent transmission intensification in rural south-western Nigeria.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-026-50058-4.