A study led by the Liverpool School of Tropical Medicine and the Centre for Research in Infectious Diseases (CRID) in Cameroon has identified a DNA marker linked to pyrethroid resistance in malaria-carrying mosquitoes. The marker was found in a gene coding for cytochrome P450, an enzyme that allows mosquitoes to survive exposure to pyrethroids, which are widely used insecticides on bed nets.
The findings, published in Science Translational Medicine, are expected to support improved management strategies for insecticide resistance and help reduce malaria cases in sub-Saharan Africa, where most global cases occur.
Professor Charles Wondji, Professor of Genetics and Vector Biology at Liverpool School of Tropical Medicine and lead author on the study, stated: "Our study designed field-applicable tools to easily track the spread of metabolic resistance in the major malaria mosquito species and assess its impact on control interventions. These important findings can help to maintain the effectiveness of insecticide-based tools such as bed nets which remain a cornerstone of malaria prevention."
Efforts such as bed nets and indoor spraying have played a key role in controlling malaria. However, over the past decade, progress has slowed due to increased resistance among mosquitoes. This resistance is often caused by metabolic processes involving detoxification enzymes.
Globally, malaria continues to be a significant health issue with approximately 200 million cases and 600,000 deaths each year. Addressing insecticide resistance is seen as essential for improving vector control strategies and reducing these numbers.
While previous research had identified genetic markers for other types of resistance, finding DNA-based mechanisms responsible for metabolic resistance had been difficult until now. This study is the first to identify such a marker for metabolic pyrethroid resistance in Anopheles gambiae populations from West and Central Africa.
Using this marker, researchers developed a diagnostic test that can detect and monitor pyrethroid resistance. The test also helps assess possible cross-resistance to new insecticides and informs decisions about which bed nets may be most effective based on local mosquito genetics.
