The use of insecticides in the home can have a significant impact on the development of resistance in disease-carrying mosquitoes and reduce the effectiveness of insecticides.
Vector biologists from the Liverpool School of Tropical Medicine have published a paper in The Lancet Americas Health focusing on patterns of household insecticide use in 19 countries where vector-borne diseases such as malaria and dengue are common.
While numerous studies have shown how public health measures and agricultural pesticide use contribute to the development of insecticide resistance, the report’s authors argue that household use and its impact remain poorly understood. This is especially true given the increasing resistance of vector-borne diseases worldwide and the threat they pose to human health.
A paper led by Dr Fabricio Martins looks at the impact of household insecticides on the development of resistance in Aedes aegypti mosquitoes, using Brazil as an example. They found that the frequency of KDR mutations, which cause Aedes aegypti mosquitoes to become resistant to pyrethroid insecticides (commonly used in household products and public health), nearly doubled in the six years after the Zika virus introduced household insecticides to the market in Brazil. Laboratory studies showed that nearly 100 percent of mosquitoes that survived exposure to household insecticides carried multiple KDR mutations, while those that died did not.
The study also found that the use of household insecticides is widespread, with about 60% of residents in 19 endemic areas regularly using household insecticides for personal protection.
They argue that such poorly documented and unregulated use could reduce the effectiveness of these products and also impact key public health measures such as the use of insecticide-treated nets and indoor residual spraying of insecticides.
Further research is needed to examine the direct and indirect effects of household insecticides, their risks and benefits to human health, and the implications for vector control programmes.
The report’s authors suggest that policymakers develop additional guidance on household pesticide management to ensure these products are used effectively and safely.
Dr Martins, a research fellow in vector biology, said: “This project grew out of field data I collected while working closely with communities in Brazil to find out why Aedes mosquitoes were developing resistance, even in areas where public health programmes had stopped using pyrethroids.
”Our team is expanding the analysis to four states in northwestern Brazil to better understand how household insecticide use drives selection for genetic mechanisms associated with pyrethroid resistance.
”Future research on cross-resistance between household insecticides and public health products will be critical for evidence-based decision-making and development of guidelines for effective vector control programs.”
Post time: May-07-2025