Escalating pyrethroid resistance in Anopheles funestus increases Plasmodium transmission.
6 affiliations
- 1Medical Entomology Department, Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon. [email protected].
- 2Faculty of Sciences, University of Yaoundé I, 337, Yaoundé, Cameroon. [email protected].
- 3Medical Entomology Department, Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon.
- 4Faculty of Sciences, University of Yaoundé I, 337, Yaoundé, Cameroon.
- 5Medical Entomology Department, Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon. [email protected].
- 6Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK. [email protected].
Abstract
Background
The swift rise in pyrethroid resistance among malaria vectors poses a significant challenge to global malaria control. Although vector control tools have advanced, limited understanding of the vectorial capacity of highly pyrethroid-resistant mosquitoes hinders accurate predictions of how new interventions will affect malaria transmission in these resilient populations. Consequently, further research is needed to elucidate how escalating resistance influences mosquito vectorial capacity and shapes malaria transmission dynamics.Methods
Wild Anopheles funestus s.l. mosquitoes were sampled from households in Adamaoua and Centre regions of Cameroon between February and September 2021 using a Prokopack aspirator. Phenotypic resistance to pyrethroids (permethrin, deltamethrin, alphacypermethrin) was assessed using WHO tube bioassays at diagnostic dose (DD), as well as at 5 × and 10 × DD. Plasmodium sporozoite infections were detected using TaqMan and nested PCR assays, and key resistance markers were genotyped by allele-specific PCR. Pearson's chi-squared tests and odds ratio were applied to examine the associations between resistance phenotypes, genotypes, and infection status.Results
Mosquitoes from Cameroon displayed low mortality rates in Mibellon, with only 33% mortality at the diagnostic dose (DD) and less than 95% mortality at 5 × and 10 × DD. In contrast, Elende populations exhibited lower resistance intensity. Sporozoite infection rates were very high in both collection sites (8.8% and 6% in Mibellon and Elende, respectively). Mosquitoes killed by elevated doses of type II pyrethroids were significantly more infected with Plasmodium than survivors (p < 0.05). Additionally, those surviving the highest deltamethrin doses showed reduced vectorial capacity compared to those surviving the 1 × diagnostic dose (OR = 2.8; 95% CI 1.1-7.3; p = 0.041). The persistence of elevated Plasmodium infection rates in mosquitoes surviving the highest permethrin concentrations underscores the direct impact of pyrethroid resistance escalation in driving malaria transmission. Genotypic analysis identified the L119F-GSTe2 mutation as associated with both resistance escalation and increased Plasmodium transmission whereas an opposite effect was observed for the P450 CYP9K1 with homozygote resistant 454A-CYP9K1 less infected than susceptible.Conclusions
These findings highlight the urgent need for effective resistance management strategies to combat escalating pyrethroid resistance, while supporting the sustained use of type II pyrethroids, which remain effective against key Plasmodium-transmitting populations.
Related
- Genomic Surveillance Reveals Clusters of Plasmodium falciparum Antimalarial Resistance Markers in Eswatini, A Low-Transmission Setting
- Metabolic resistance drives cross-resistance in Aedes albopictus to pyriproxyfen and pyrethroid insecticides
- Detection of Plasmodium falciparum-infected Anopheles sergentii with reduced insecticide net susceptibility in a dryland ecosystem of the Kenyan Rift Valley: implications for malaria surveillance and vector control
- Plasmodium protein kinase 2 is required for ookinete-to-oocyst transition and parasite transmission
- Spatial and temporal dynamics of insecticide resistance in the Anopheles gambiae complex, with a focus on Anopheles coluzzii, in Burkina Faso
BibTeX
@article{fonkou2026escalating,
title = {{Escalating pyrethroid resistance in Anopheles funestus increases Plasmodium transmission.}},
author = {Brice Natchema Soh Fonkou and Magellan Tchouakui and Benjamin Menze and Jeannette Tombi and Charles Sinclair Wondji},
journal = {Malaria journal},
year = {2026},
month = aug,
doi = {10.1186/s12936-026-06094-6},
url = {https://europepmc.org/article/MED/43009960},
note = {CC BY},
}
RIS
TY - JOUR
TI - Escalating pyrethroid resistance in Anopheles funestus increases Plasmodium transmission.
AU - Brice Natchema Soh Fonkou
AU - Magellan Tchouakui
AU - Benjamin Menze
AU - Jeannette Tombi
AU - Charles Sinclair Wondji
PY - 2026
DA - 2026/08/13
JO - Malaria journal
DO - 10.1186/s12936-026-06094-6
UR - https://europepmc.org/article/MED/43009960
AB - Background The swift rise in pyrethroid resistance among malaria vectors poses a significant challenge to global malaria control. Although vector control tools have advanced, limited understanding of the vectorial capacity of highly pyrethroid-resistant mosquitoes hinders accurate predictions of how new interventions will affect malaria transmission in these resilient populations. Consequently, further research is needed to elucidate how escalating resistance influences mosquito vectorial capacity and shapes malaria transmission dynamics.Methods Wild Anopheles funestus s.l. mosquitoes were sampled from households in Adamaoua and Centre regions of Cameroon between February and September 2021 using a Prokopack aspirator. Phenotypic resistance to pyrethroids (permethrin, deltamethrin, alphacypermethrin) was assessed using WHO tube bioassays at diagnostic dose (DD), as well as at 5 × and 10 × DD. Plasmodium sporozoite infections were detected using TaqMan and nested PCR assays, and key resistance markers were genotyped by allele-specific PCR. Pearson's chi-squared tests and odds ratio were applied to examine the associations between resistance phenotypes, genotypes, and infection status.Results Mosquitoes from Cameroon displayed low mortality rates in Mibellon, with only 33% mortality at the diagnostic dose (DD) and less than 95% mortality at 5 × and 10 × DD. In contrast, Elende populations exhibited lower resistance intensity. Sporozoite infection rates were very high in both collection sites (8.8% and 6% in Mibellon and Elende, respectively). Mosquitoes killed by elevated doses of type II pyrethroids were significantly more infected with Plasmodium than survivors (p < 0.05). Additionally, those surviving the highest deltamethrin doses showed reduced vectorial capacity compared to those surviving the 1 × diagnostic dose (OR = 2.8; 95% CI 1.1-7.3; p = 0.041). The persistence of elevated Plasmodium infection rates in mosquitoes surviving the highest permethrin concentrations underscores the direct impact of pyrethroid resistance escalation in driving malaria transmission. Genotypic analysis identified the L119F-GSTe2 mutation as associated with both resistance escalation and increased Plasmodium transmission whereas an opposite effect was observed for the P450 CYP9K1 with homozygote resistant 454A-CYP9K1 less infected than susceptible.Conclusions These findings highlight the urgent need for effective resistance management strategies to combat escalating pyrethroid resistance, while supporting the sustained use of type II pyrethroids, which remain effective against key Plasmodium-transmitting populations.
SN - 1475-2875
ER -