Scientists from the Institut Pasteur in French Guiana contributed to an international surveillance study of populations of the
Anopheles darlingi mosquito, the primary vector of malaria in South America.
The study, conducted by a team of scientists from the
Harvard T.H. Chan School of Public Health, is the first to have sequenced more than 1,000 complete genomes of mosquitoes from six countries in South America. The analysis of genetic diversity by the scientists reveals recent evolutionary changes in the genome concerning genes for potential insecticide resistance. The results were published in
Science on March 26, 2026.
The Anopheles darlingi mosquito, the primary vector of malaria in South America, is evolving to adapt to insecticides. A female Anopheles darlingi mosquito raised at the Vectopôle of the Institut Pasteur in French Guiana. Anopheles darlingi is the main malaria vector in French Guiana.
© Institut Pasteur de la Guyane - photo Romuald Carinci et Pascal Gaborit For one year, scientists collected female mosquitoes of the species
Anopheles darlingi from 16 sites across six South American countries: Brazil, Peru, Venezuela, Colombia, Guyana, and French Guiana. The study of the 1,094 genomes revealed that selective pressure for alleles potentially resistant to insecticides exists on some of these genes in these South American mosquito populations.
The genetic variations associated with these resistances were linked to geographical areas where agriculture is the main activity. Therefore, this genetic signature could be due to agricultural insecticides rather than those specifically used for vector control.
The researchers also observed significant genetic divergence among Anopheles darlingi mosquitoes across the continent, for example, between those collected in French Guiana and those collected in Venezuela. Their observations show that the species is adapting to changes in its environment.
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Surveillance activities of mosquito populations are essential to contribute to the control of vector-borne diseases," emphasizes Jean-Bernard Duchemin, a researcher in the Medical Entomology unit at the Institut Pasteur in French Guiana and an author of the study.
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These results show the persistent challenges posed by vector diversity for malaria elimination in the Americas," adds Mathilde Gendrin, head of the Insect Vector Microbiota laboratory at the Institut Pasteur in French Guiana, an author of the study.
Ahead of the upcoming
One Health Summit to be held in Lyon on April 7, this publication reminds us of the importance of surveilling infectious disease vectors, particularly mosquitoes, in the context of adaptation to environmental transformations. The Institut Pasteur continues its commitment through its participation in the Summit and the creation of a Research Center on Vector-Borne Diseases.