New type of mosquito identified on the coast of East Africa
This newly discovered mosquito, provisionally named the Pwani molecular form, belongs to the Anopheles gambiae complex — a group that includes some of the world’s most important malaria vectors.
This discovery, published (16 April) in Molecular Ecology, was the result of a collaboration between the Wellcome Sanger Institute, the University of Glasgow, and the Ifakara Health Institute in Tanzania. The team’s work reveals the presence of a genetically divergent mosquito that could have profound implications for malaria vector surveillance and insecticide-based control strategies in the region.
Using genetic sequencing, researchers established that this new type of mosquito is restricted to the coastal parts of Tanzania and Kenya. Notably, it appears to have a unique insecticide resistance profile, and unlike other malaria vectors in the region, it appears to lack common genetic markers of resistance.
The researchers say this suggests the Pwani mosquito is either more vulnerable to insecticides or has developed resistance in a completely different way, something they believe urgently needs to be studied.
Currently, chemical insecticides are central to the control of disease vectors such as mosquitoes. The control of mosquitoes through insecticides helps avert millions of cases of malaria annually, a disease that continues to kill 600,000 people every year.
The newly identified mosquito shows a strong genetic differentiation from other species within the Anopheles gambiae complex, suggesting it may have evolved distinct ecological or behavioural traits.
While it is not yet confirmed whether the Pwani molecular form actively transmits malaria, its detection in malaria-endemic areas and within a complex with some of the most important malaria vectors in the world makes it a potential target for investigation.
Although further research is needed, these findings suggest that current control approaches may not be able to target the newly discovered Pwani mosquito effectively.
“The discovery of the Pwani molecular form reveals gaps in our understanding of mosquito diversity in malaria-endemic areas. Its distinct insecticide profile and restricted geographical presence suggests that this mosquito species possibly plays a potential role in sustaining malaria transmission during the dry season, when other vectors are less active in these respective areas. This could also explain the continued persistent cases of malaria in these locations despite widespread use of bed nets.”
Sophia Mwinyi, lead author at the University of Glasgow and Ifakara Health Institute
“By using genetics, we can help stay ahead of the game in the fight against malaria. Understanding the DNA of mosquito populations helps scientists and public health officials design better interventions to stop disease transmission.”
Dr Fredros Okumu, co-senior author at the University of Glasgow and Ifakara Health Institute
More information
Publication:
S. Mwinyi, K. Bennett, S. Nagi, et al. (2025) ‘Genomic Analysis Reveals a New Cryptic Taxon within the Anopheles gambiae Complex with a Distinct Insecticide Resistance Profile in the Coast of East Africa’. Molecular Ecology. DOI: 10.1111/mec.17762
Funding:
The study was funded by Wellcome, the Bill & Melinda Gates Foundation and the UK Medical Research Council. A full acknowledgement list can be found in the publication.
