Insecticide Resistance Management in Malaria Vector Control

Insecticide resistance management (IRM) has become a cornerstone of malaria vector control as widespread resistance to pyrethroids and other chemical classes threatens the efficacy of bed nets and indoor spraying. IRM integrates surveillance, novel chemistries and adaptive deployment strategies to preserve the utility of existing insecticides while guiding the introduction of new active ingredients. Key approaches include rotating insecticide classes, deploying mixtures or mosaics of active compounds and combining interventions such as long-lasting insecticidal nets (LLINs) with indoor residual spraying. Effective IRM rests on robust entomological monitoring to detect emerging resistance, coupled with modelling and mapping tools that forecast resistance spread and inform targeted responses. These measures must be supported by policy frameworks that ensure supply of alternative insecticides, capacity building for national programmes and engagement with agricultural sectors to reduce non-public-health use of shared chemistries. As malaria transmission persists in diverse ecological settings, IRM strategies must be tailored to local vector species, resistance mechanisms and transmission dynamics to sustain gains in malaria control and move towards elimination.

Research from Nature Portfolio

Modelling studies have refined our understanding of direct and indirect protection afforded by LLINs under varying levels of pyrethroid resistance. Dynamic simulations indicate that community-wide usage confers benefits even at low coverage and that resistance erodes insecticidal but not physical barrier effects, underscoring the continued value of LLINs relative to untreated nets. Biochemical investigations have elucidated how chlorfenapyr, a pro-insecticide, is activated by mosquito cytochrome P450 enzymes commonly upregulated in pyrethroid-resistant populations. These studies identify specific P450 isoforms that convert chlorfenapyr into its bioactive metabolite, tralopyril, and reveal interactions between chlorfenapyr and pyrethroids that may influence efficacy. Such mechanistic insights inform the optimal ratio of active ingredients in dual-AI nets and guide the selection of marker assays to monitor chlorfenapyr sensitivity in field populations.

Insecticide Resistance Management in Malaria Vector Control publication trend

The graph below shows the total number of articles in insecticide resistance management in malaria vector control across all publications each year (not limited to Nature Index journals).

Technical terms

Long-lasting insecticidal net (LLIN): A bed net treated with insecticide that remains effective for several years under field conditions. Pyrethroid resistance: The ability of mosquito populations to survive exposure to pyrethroid insecticides, often via metabolic or target-site mechanisms. Pro-insecticide: A compound requiring metabolic activation by the vector to exert its toxic effect. Cytochrome P450 (P450): A family of enzymes in mosquitoes that can metabolise insecticides and contribute to resistance. Cellular automata model: A computational approach that simulates spatial and temporal changes in resistance based on local rules and environmental drivers.

References

1. Efficacy of pyriproxyfen-pyrethroid long-lasting insecticidal nets (LLINs) and chlorfenapyr-pyrethroid LLINs compared with pyrethroid-only LLINs for malaria control in Benin: a cluster-randomised, superiority trial. The Lancet (2023).
2. Effectiveness of long-lasting insecticidal nets with pyriproxyfen–pyrethroid, chlorfenapyr–pyrethroid, or piperonyl butoxide–pyrethroid versus pyrethroid only against malaria in Tanzania: final-year results of a four-arm, single-blind, cluster-randomised trial. The Lancet Infectious Diseases (2023).
3. Quantifying the direct and indirect protection provided by insecticide treated bed nets against malaria. Nature Communications (2023).
4. Spatio-temporal characterization of phenotypic resistance in malaria vector species. BMC Biology (2024).
5. Chlorfenapyr metabolism by mosquito P450s associated with pyrethroid resistance identifies potential activation markers. Scientific Reports (2023).
6. Implementation of the global plan for insecticide resistance management in malaria vectors: progress, challenges and the way forward. Malaria Journal (2015).