Kenyans are facing a rising risk of malaria infections after new research revealed that a major mosquito species has evolved both genetically and behaviorally, making traditional prevention methods less effective.
The study, published on September 18 in the journal Science, focuses on Anopheles funestus, one of Africa’s most dangerous malaria-carrying mosquitoes.
Researchers found that the species has developed resistance to insecticides and has changed its behavior now biting during the day and outdoors, rather than at night when bed nets offer protection.
These changes undermine core malaria control tools such as insecticide-treated bed nets and indoor spraying.
The research involved sequencing over 650 mosquito genomes from across Africa including historic samples from the 1920s to trace how the mosquito has evolved over time.
The large-scale study was a collaboration between the Kenya Medical Research Institute (KEMRI), scientists from 13 African countries, and the Wellcome Sanger Institute in the UK.
“For too long, An. funestus has been overlooked, despite its critical role in malaria transmission,” said Professor Charles Wondji of the Liverpool School of Tropical Medicine and the Centre for Research in Infectious Diseases in Cameroon. “This research is a major step toward more effective control measures.”
The study found that resistance mutations date back as far as the 1960s, indicating that insecticide resistance has been evolving for decades.
Newer mutations appear to have emerged in response to modern chemicals, making mosquito control even more challenging.
Another key finding is the genetic complexity of An. funestus populations. Some groups of mosquitoes mix across the continent, while others even those geographically close remain genetically distinct.
This diversity complicates efforts to create universal interventions.
“We see some mosquito populations sharing genetic traits across vast distances, while others remain isolated even when living nearby,” said Dr. Mara Lawniczak, lead author and group leader at the Wellcome Sanger Institute.
“Even if the Gambiae Complex were eliminated, malaria would persist unless An. funestus is also effectively addressed.”
The findings highlight the urgent need to diversify malaria control strategies.
Beyond bed nets and insecticide spraying, researchers are now exploring advanced tools like gene drives genetic modifications that can suppress or alter mosquito populations.
The research also underscored the value of museum collections. Historical mosquito specimens provided crucial insights into long-term evolutionary trends.
“When people ask why we still collect specimens, studies like this show how important they are,” said Erica McAlister, senior curator at the Natural History Museum in London. “We often don’t know the full value of what we have until years later.”
The discovery follows another warning sign: in 2023, KEMRI confirmed the presence of Anopheles stephensi in Kenya a mosquito species that thrives in both rural and urban environments, further complicating malaria control efforts.
With malaria still claiming over 500,000 lives annually in Africa, health experts warn that without new and adaptive strategies, decades of progress could be undone.
