Biology subjects

Hamid-Adiamoh, M.

Publications and source records attributed to Hamid-Adiamoh, M..

3 recordsLinked to original sources

bioRxiv2026

Genomic signatures of selection in Anopheles funestus reveal shared and population-specific adaptive variation across African populations

Insecticide resistance in Anopheles funestus threatens malaria vector control across sub-Saharan Africa, yet genomic signatures of selection across geographically structured populations remain poorly understood. We analysed whole-genome sequence data from 635 An. funestus mosquitoes from West (Senegal, Guinea, Nigeria), Central (Cameroon), and East Africa (Kenya) to characterise population structure and identify targets of recent positive selection. Population genomic analyses revealed strong differentiation between East African and West/Central African populations, with finer-scale structuring within West Africa. Genome-wide selection scans using H12 identified sweep regions on chromosome arms 2RL and 3RL, overlapping a cytochrome P450 cluster and the gamma-aminobutyric acid (GABA) receptor locus respectively. iSAFE prioritised candidate variants within these sweeps: non-synonymous substitutions in CYP6A14 were identified at high frequencies in Guinea, Nigeria, and Cameroon, while population-restricted variants implicated octopamine receptor genes on 2RL and the GABA receptor on 3RL. Diplotype clustering and copy number variation analyses confirmed the causal role of candidate variants, embedded within extended haplotypes of reduced heterozygosity consistent with recent positive selection. These findings demonstrate that adaptive evolution in An. funestus reflects both shared and population-specific selective processes shaped by geography and ecological context. Whereas selection on detoxification pathways appears widespread, localised signals in neuromodulatory loci, including the GABA receptor and octopamine-related genes, reveal that biological systems beyond metabolic resistance contribute to mosquito adaptation. The convergence of selective signals across these gene classes highlights neuromodulatory pathways as potential complementary targets for next-generation vector control strategies.

genomics↗

bioRxiv2026

Soda-baited RNAi Yeast Insecticides as Effective Attractive Targeted Sugar Baits (ATSBs) for Mosquito Control

BackgroundAttractive Targeted Sugar Baits (ATSBs) are a promising, environmentally friendly approach for mosquito control, but the direct field application, scalability and long-term effectiveness of ATSBs across diverse mosquito species remain significant challenges. Methodology/Principal FindingsWe assessed the efficacy of a genetically engineered RNA interference (RNAi) yeast strain (Sh.463_56.10R) formulated in three sugar baits, soda (Coca-ColaTM), 10% sucrose, and a commercial mosquito bait (BaitStabTM), on Aedes, Anopheles and Culex mosquitoes. All RNAi yeast bait formulations induced significantly higher mean mortality (87-100%) compared to the control groups (0-9%; P<0.0001), but mosquitoes exhibited a higher feeding preference for RNAi yeast-soda baits, which induced mortality rates of 94-100% (P < 0.0001) recorded across all mosquito species. Additionally, to assess the competitiveness of the RNAi yeast-soda bait to other tropical sugar sources, semi-field choice assays were conducted in Trinidad, West Indies using competing flowering plants and fruits typically found in residential environments. The RNAi yeast-soda ATSB continued to perform well in the presence of competing floral and fruit sugar sources during both Aedes albopictus and Culex quiquefasciatus trials, though the presence of several fruits and flowers did reduce A. aegypti mortality, suggesting that further field testing will be necessary. The residual activity of the Sh.463_56.10R + soda formulation was retained for at least 14 months, with sustained 100% mortality in C. quinquefasciatus and 93-100% mortality in Aedes aegypti, Anopheles gambiae and Anopheles stephensi. The RNAi yeast-soda ATSB also performed well in semi-field studies performed with a prototype soda bottle feeder. Conclusions/SignificanceThis study demonstrates the potential of soda-baited RNAi yeast as a potent, long-lasting, and scalable platform for ATSB-based mosquito control as a component of integrated vector management programs. Author SummaryMosquito-borne diseases continue to affect millions of people worldwide, and current mosquito control methods face challenges such as low public uptake, insecticide resistance and environmental concerns. Here we evaluated a new and environmentally friendly approach to mosquito control using ATSBs. We tested genetically engineered species-specific yeast producing RNAi molecules capable of killing mosquitoes that feed on it. We mixed the yeast with three different sugar baits, including soda (Coca-ColaTM), 10% sucrose, and the commercial mosquito bait BaitStabTM formulation, and evaluated how well they worked against different mosquitoes. The results showed that the RNAi yeast mixed with soda was the most effective, killing up to 100% of mosquitoes in laboratory and outdoor tests. The bait remained effective in the presence of many competing natural tropical fruit and floral sugar sources. Remarkably, the bait, which can be delivered in a soda bottle feeder, stayed active for at least 14 months under simulated field conditions. These findings suggest that soda-based RNAi yeast baits could provide a practical, long-lasting and scalable tool for mosquito control and may help strengthen future strategies to reduce mosquito-borne diseases.

genetics↗

bioRxiv2020

Biting and resting preferences of malaria vectors in The Gambia

BackgroundThe scale-up of indoor residual spraying and long-lasting insecticidal nets, together with other interventions have considerably reduced the malaria burden in The Gambia. This study examined the biting and resting preferences of the local insecticide-resistant vector populations few years following scale-up of anti-vector interventions. MethodIndoor and outdoor-resting Anopheles gambiae mosquitoes were collected between July and October 2019 from ten villages in five regions in The Gambia using pyrethrum spray collection (indoor) and prokopack aspirator from pit traps (outdoor). Polymerase chain reaction assays were performed to identify molecular species, insecticide resistance mutations, Plasmodium infection rate and host blood meal. ResultsA total of 844 mosquitoes were collected both indoors (421, 49.9%) and outdoors (423, 50.1%). Four main vector species were identified, including An. arabiensis (indoor: 15%, outdoor: 26%); An. coluzzii (indoor: 19%, outdoor: 6%), An. gambiae s.s. (indoor: 11%, outdoor: 16%), An. melas (indoor: 2%, outdoor: 0.1%) and hybrids of An. coluzzii-An. gambiae (indoors: 3%, outdoors: 2%). A significant preference for outdoor resting was observed in An. arabiensis (Pearson X2=22.7, df=4, P<0.001) and for indoor resting in An. coluzzii (Pearson X2=55.0, df=4, P<0.001). Prevalence of the voltage-gated sodium channel (Vgsc)-1014S was higher in the indoor-resting (allele freq. = 0.96, 95%CI: 0.78-1) than outdoor-resting (allele freq. = 0.82, 95%CI: 0.76-0.87) An. arabiensis population. For An. coluzzii, the prevalence of most mutation markers were higher in the outdoor (allele freq. = 0.92, 95%CI: 0.81-0.98) than indoor-resting (allele freq. = 0.78, 95%CI: 0.56-0.86) mosquitoes. Sporozoite positivity rate was 1.3% (95% CI: 0.5-2%). Indoor-resting An. coluzzii had mainly fed on human blood while indoor-resting An. arabiensis, animal blood. ConclusionThe indoor-resting behavior of An. arabiensis that preferred animal blood and had low sporozoite rates, may be determined by the Vgsc-1014S mutation. Control interventions may include complementary vector control approaches such as zooprophylaxis.

molecular biology↗