Browsing by Author "FOLAMADE, Joshua Kayode"

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    COMPARATIVE EXPRESSION PROFILING OF SELECTED GLUTATHIONE S-TRANSFERASE GENES IN BLOOD-FED AND DELTAMETHRIN-EXPOSED Anopheles gambiae
    (Covenant University Ota, 2025-09) FOLAMADE, Joshua Kayode; Covenant University Dissertation
    Malaria remains a leading public health challenge in sub-Saharan Africa, with Nigeria contributing the highest global burden. Anopheles gambiae is the major vector of this disease in Nigeria. Vector control strategies rely heavily on pyrethroid-based tools such as long-lasting insecticidal nets and indoor residual spraying. Metabolic resistance mediated by glutathione S-transferases (GSTs), particularly GSTe2, GSTe3, and GSTMS3, has been implicated in pyrethroid detoxification. Meanwhile, blood feeding induces profound physiological and molecular changes in mosquitoes, including alterations in detoxification pathways, suggesting a potential interaction with insecticide resistance. This study investigated how blood feeding and deltamethrin exposure influence the expression of GSTe2, GSTe3, and GSTMS3 in An. gambiae from Ota, Ogun State, Nigeria. Mosquitoes were reared from field-collected larvae and assigned to four experimental groups: blood-fed + deltamethrin exposed, blood-fed only, sugar-fed + deltamethrin exposed, and sugar-fed only (control). Susceptibility to deltamethrin was assessed using WHO bioassays and gene expression was quantified by qPCR. Results showed that blood-fed mosquitoes were significantly more susceptible to deltamethrin than sugar-fed counterparts, with higher mortality and faster knockdown times. At the molecular level, GSTe2 expression was generally down-regulated following deltamethrin exposure, while GSTe3 and GSTMS3 exhibited variable responses depending on feeding status. It was observed that blood feeding was the most consistent factor influencing GST expression, with insecticide exposure exerting context-dependent effects. These findings highlight that blood feeding modulates detoxification gene expression and susceptibility outcomes in An. gambiae, which implies dynamic physiological influences on resistance phenotypes. By integrating ecological behavior with molecular resistance mechanisms, this study underscores the importance of accounting for feeding status in resistance monitoring and vector control strategies. Locally relevant data such as these are critical for guiding malaria control interventions in Nigeria’s high-burden regions.