Genomic analysis reveals selection pressure and the emergence of molecular insecticide resistance in the malaria vector, Anopheles gambiae, from Western Ethiopia.
8 affiliations
- 1Ethiopian Public Health Institute, Addis Ababa, Ethiopia. [email protected].
- 2Center for Pathobiology, Aklilu Lemma Institute of Health Research, Addis Ababa University, Addis Ababa, Ethiopia. [email protected].
- 3Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
- 4Center for Pathobiology, Aklilu Lemma Institute of Health Research, Addis Ababa University, Addis Ababa, Ethiopia.
- 5Ethiopian Public Health Institute, Addis Ababa, Ethiopia.
- 6Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
- 7Ellison Institute of Technology, Littlemore, Oxford, OX4 4GE, UK.
- 8Center for Pathobiology, Aklilu Lemma Institute of Health Research, Addis Ababa University, Addis Ababa, Ethiopia. [email protected].
Abstract
Background
Insecticide resistance poses a significant challenge to malaria control, driven by diverse molecular mechanisms, whose distribution remains poorly characterized in Ethiopia. This study presents the first results using whole-genome sequence data of Anopheles gambiae from Ethiopia, confirming its presence in the western region of the country and expanding its known geographical distribution.Methods
Analysis of single-nucleotide polymorphisms and copy number variants focussed on key target-site insecticide resistance genes, including the voltage-gated sodium channel (Vgsc), acetylcholinesterase-1 (Ace-1), the gamma-aminobutyric acid (GABA)-gated chloride channel (Rdl) gene, as well as metabolic resistance loci such as cytochrome P450s (Cyp6m2, Cyp6aa/p, Cyp9k1) and carboxylesterases (Coeae2f, Coeae2-7g).Results
Genomic analysis revealed high frequencies of Vgsc-L995F (kdr-west) mutations, alongside amplifications at Cyp6aa/p, Cyp9k1, and Gste2. Notably, frequencies of Vgsc and Gste2 variants exhibited differences on a local scale, while Vgsc and Cyp9k1 variant frequencies also fluctuated seasonally. Findings highlight the need for site-specific monitoring on a fine temporal scale. Furthermore, genome-wide selection scans using phased haplotypes identified emerging signals of selection at loci with a potential link to insecticide resistance, including a signal spanning 2L:33,767,545-34,391,778, which expands the catalogue of candidate loci for functional validation.Conclusions
Together, the presence of high frequencies of known insecticide resistance markers suggests that An. gambiae populations may be largely refractory to pyrethroids and moderately resistant to organophosphate (OPs) insecticides in western Ethiopia. Findings necessitate a better understanding of the An. gambiae geographical distribution in Ethiopia, accompanied by resistance-informed malaria control interventions targeting the vector.
Related
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- Challenges and opportunities for strengthening South American responses to insecticide resistance in disease vectors: Lessons from the WINSA workshop in Bogotá, Colombia
- Patterns of insecticide resistance in Aedes aegypti and Aedes albopictus in different cities across Cameroon
BibTeX
@article{gemechu2026genomic,
title = {{Genomic analysis reveals selection pressure and the emergence of molecular insecticide resistance in the malaria vector, Anopheles gambiae, from Western Ethiopia.}},
author = {Fekadu Gemechu and Kelly L Bennett and Sisay Dugassa and Anastasia Hernandez-Koutoucheva and Araya Eukubay and Alistair Miles and Deriba Abera and Chris S Clarkson and Lemu Golassa},
journal = {Parasites \& vectors},
year = {2026},
month = aug,
doi = {10.1186/s13071-026-07582-z},
url = {https://europepmc.org/article/MED/42972566},
note = {CC BY},
}
RIS
TY - JOUR
TI - Genomic analysis reveals selection pressure and the emergence of molecular insecticide resistance in the malaria vector, Anopheles gambiae, from Western Ethiopia.
AU - Fekadu Gemechu
AU - Kelly L Bennett
AU - Sisay Dugassa
AU - Anastasia Hernandez-Koutoucheva
AU - Araya Eukubay
AU - Alistair Miles
AU - Deriba Abera
AU - Chris S Clarkson
AU - Lemu Golassa
PY - 2026
DA - 2026/08/05
JO - Parasites & vectors
DO - 10.1186/s13071-026-07582-z
UR - https://europepmc.org/article/MED/42972566
AB - Background Insecticide resistance poses a significant challenge to malaria control, driven by diverse molecular mechanisms, whose distribution remains poorly characterized in Ethiopia. This study presents the first results using whole-genome sequence data of Anopheles gambiae from Ethiopia, confirming its presence in the western region of the country and expanding its known geographical distribution.Methods Analysis of single-nucleotide polymorphisms and copy number variants focussed on key target-site insecticide resistance genes, including the voltage-gated sodium channel (Vgsc), acetylcholinesterase-1 (Ace-1), the gamma-aminobutyric acid (GABA)-gated chloride channel (Rdl) gene, as well as metabolic resistance loci such as cytochrome P450s (Cyp6m2, Cyp6aa/p, Cyp9k1) and carboxylesterases (Coeae2f, Coeae2-7g).Results Genomic analysis revealed high frequencies of Vgsc-L995F (kdr-west) mutations, alongside amplifications at Cyp6aa/p, Cyp9k1, and Gste2. Notably, frequencies of Vgsc and Gste2 variants exhibited differences on a local scale, while Vgsc and Cyp9k1 variant frequencies also fluctuated seasonally. Findings highlight the need for site-specific monitoring on a fine temporal scale. Furthermore, genome-wide selection scans using phased haplotypes identified emerging signals of selection at loci with a potential link to insecticide resistance, including a signal spanning 2L:33,767,545-34,391,778, which expands the catalogue of candidate loci for functional validation.Conclusions Together, the presence of high frequencies of known insecticide resistance markers suggests that An. gambiae populations may be largely refractory to pyrethroids and moderately resistant to organophosphate (OPs) insecticides in western Ethiopia. Findings necessitate a better understanding of the An. gambiae geographical distribution in Ethiopia, accompanied by resistance-informed malaria control interventions targeting the vector.
SN - 1756-3305
ER -