Researchers from LSTM and partners in Cameroon and Kenya have contributed to a new study that shows how the Anopheles funestus mosquito is evolving in response to malaria control efforts.
Published in Science and led by the Wellcome Sanger Institute, the research involved the sequencing of hundreds of An. funestus mosquitoes collected throughout the continent to explore the genetic changes driving its adaptation to control methods with nearly half provided by Prof Charles Wondji’s team.
The results of the study provide a new understanding of An. funestus that can be used to inform further genomic surveillance work towards malaria elimination in sub-Saharan Africa. The mosquito species An. funestus is one of the most widespread in Africa and a leading transmitter of malaria.
Professor Charles Wondji from LSTM and the Centre for Research In Infectious Disease (CRID) in Cameroon, as well as other researchers from LSTM, the Kenya Medical Research Institute (KEMRI) and other institutions across Africa and Europe were involved in the study.
Professor Wondji said: “For too long An. funestus has been neglected despite its key role in malaria transmission across Africa. I am thus delighted that this continent-wide whole genome study of the genetic structure of An. funestus is now published. My team at LSTM/CRID is proud to have contributed to this major milestone that will facilitate the implementation of future control interventions against this major vector.”
Having a comprehensive understanding of the genetics of each major malaria-transmitting mosquito species is essential for implementing effective malaria control and preventing deaths.
Mosquito biologists across Africa together with the team at the Sanger Institute collected and sequenced the whole genomes of both modern and historic An. funestus mosquito specimens.
They found high levels of genetic variation in An. funestus across Africa, showing how some populations mix widely, while others remain separate. Such population structure has important implications for mosquito control.
Professor Wondji added: “These findings validate patterns of insecticide resistance elucidated by my team showing for example that Cameroon (Central Africa) and Uganda (East) tended to share the same molecular markers (e.g. G454A-CYP9K1) of metabolic resistance to pyrethroids but different with West and Southern Africa.”
By looking at the DNA of the historic samples, the team was also able to highlight the fast-evolving nature of An. funestus. One key insecticide resistance conferring mutation, which is widespread among the modern populations, was already present in the mosquitoes from the 1960s. However, other resistance conferring mutations were absent from the historic mosquitoes, suggesting that these became beneficial for the mosquitoes only later, as different insecticides were used in subsequent decades.
The research also discovered that the innovative gene drive system developed for An. gambiae can be adapted to work in An. funestus as well.
Dr Marilou Boddé, a first author on this work and Postdoctoral Fellow formerly at the Wellcome Sanger Institute and now at Institut Pasteur de Madagascar and LIB Bonn, Germany, said: “An. funestus is genetically complex and evolving fast under pressure from insecticide use. This work is progress in generating a foundational genomic understanding of An. funestus. The insights from this study are crucial for designing future tools that need to work across entire continents for the benefit of those living in countries affected by malaria."
To read the full paper and press release, please visit the Wellcome Sanger Institute website.