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High insecticide resistance mediated by different mechanisms in Culex quinquefasciatus populations from the city of Yaoundé, Cameroon

Scientific Reports – 2021


Abdou Talipouo, Konstantinos Mavridis, Elysée Nchoutpouen, Borel Djiappi‑Tchamen, Emmanouil Alexandros Fotakis, Edmond Kopya, Roland Bamou, Sévilor Kekeunou, Parfait Awono‑Ambene1, Vasileia Balabanidou, Sofia Balaska, Charles Sinclair Wondji, John Vontas & Christophe Antonio‑Nkondjio


Scientific Reports



Culex mosquitoes particularly Culex quinquefasciatus are important arboviral and filariasis vectors,

however despite this important epidemiological role, there is still a paucity of data on their bionomics.

The present study was undertaken to assess the insecticide resistance status of Cx. quinquefasciatus

populations from four districts of Yaoundé (Cameroon). All Culex quinquefasciatus populations

except one displayed high resistance to bendiocarb and malathion with mortalities ranging from

0 to 89% while high resistance intensity against both permethrin and deltamethrin was recorded.

Molecular analyses revealed high frequencies of the ACE-1 G119S mutation (ranging from 0 to 33%)

and kdr L1014F allele (ranging from 55 to 74%) in all Cx. quinquefasciatus populations. Significant

overexpression was detected for cytochrome P450s genes CYP6AA7 and CYP6Z10, as well as for

Esterase A and Esterase B genes. The total cuticular hydrocarbon content, a proxy of cuticular

resistance, was significantly increased (compared to the S-lab strain) in one population. The study

confirms strong insecticide resistance mediated by different mechanisms in Cx. quinquefasciatus

populations from the city of Yaoundé. The expansion of insecticide resistance in Culex populations

could affect the effectiveness of current vector control measures and stress