Impact of insecticide resistance evolution on malaria vector control

Area of Science:

• Vector control
• Entomology
• Population genetics

Background:

• Insecticide-treated nets (ITNs) are crucial for malaria vector control.
• Insecticide resistance (IR) poses a significant threat to ITN efficacy.
• Understanding the dual impact of ITNs on IR evolution and malaria control is critical, especially with next-generation mixture ITNs (NGM-ITNs).

Purpose of the Study:

• To model the simultaneous impact of ITNs on malaria transmission and IR evolution.
• To compare the effectiveness of pyrethroid-only ITNs (PYR-ITNs) and NGM-ITNs.
• To assess the role of insecticide resistance management (IRM) in ITN evaluations.

Main Methods:

• Development of a mosquito population dynamics and genetics model.
• Simulations exploring the long-term impacts of ITN interventions.
• Analysis of ITN coverage, insecticide decay, and net retention.

Main Results:

• Higher ITN coverage, regardless of type, improved malaria vector control.
• NGM-ITNs demonstrated superior efficacy in both malaria transmission control and IRM compared to PYR-ITNs.
• Even at lower coverage, NGM-ITNs provided greater benefits due to reduced selection pressure and IRM.

Conclusions:

• IRM must be integrated into the evaluation of NGM-ITNs.
• Current evaluation pipelines may undervalue NGM-ITNs by omitting IRM.
• Considering IRM is essential for accurately assessing the long-term effectiveness of novel malaria control interventions.