First detection of F1534C knockdown resistance mutation in Aedes aegypti(Diptera:Culicidae)from Cameroon

• 作者: Aurelie P.Yougang Basile Kamgang Theodel A.Wilson Bahun Armel N.Tedjou Daniel Nguiffo-Nguete Flobert Njiokou Charles S.Wondji
• 来源期刊: 贫困所致传染病（英文）
• 年，卷（期）: 2020,（6）
• 所属期刊栏目: RESEARCH ARTICLE
• 页码范围: 51-62
• 页数: 12页
• 语种: 英文

摘要

Background:Aedes borne viral diseases,notably dengue,are increasingly reported in Cameroon with Aedes aegypti being a major vector.Data on insecticide resistance of this vector and underlying mechanisms needed for outbreak preparedness remain scarce in Cameroon.Here,we present the nationwide distribution of insecticide resistance in Ae.aegypti and investigate the potential resistance mechanisms involved. Methods:Immature stages of Ae.aegypti were collected between March and July 2017 in 13 locations across Cam-eroon and reared until G1/G2/G3 generation.Larval,adult bioassays,and piperonyl butoxide(PBO)synergist assays were carried out according to World Health Organization guidelines.F1534C mutation was genotyped using allele specific polymerase chain reaction in field collected adults(Go)and the polymorphism of the sodium channel gene was assessed.Thex2 test was used to compare the mortality rate between bioassays with insecticides only and bioas-says after preexposure to PBO synergist. Results:Larval bioassay revealed that all the three populations tested with temephos were susceptible.Adult bioas-says showed a good level of susceptibility toward both pyrethroids tested,0.25％permethrin and 0.05％deltamethrin,with six out of 10 populations susceptible.However,two populations(Douala and Edea)were resistant[deltamethrin(73.2-92.5％mortality),permethrin(2.6-76.3％mortality)].The resistance to 4％dichlorodiphenyltrichloroethane was observed in four out of 10 populations tested(16.8-87.1％mortality).Resistance was also reported to carbamates including 0.1％propoxur(60.8-87.1％mortality)and to 0.1％bendiocarb(82.9％mortality).All populations tested were fully susceptible to 1％fenitrothion.A partial recovery of susceptibility was observed in the pyrethroid resist-ant population of Douala after pre-exposed to PBO suggesting the implication of cytochrome P450 monoxygenases permethrin resistance.Genotyping and sequencing detected the F1534C kdr mutation in the two pyrethroid resistant locations of Edea and Douala,with allelic frequency of 3.3％and 33.3％respectively.However,the high genetic diver-sity of the sodium channel gene supports the recent introduction of this mutation in Cameroon. Conclusions:This study revealed the contrasting resistance profiles to insecticides of Ae.aegypti populations in Cam-eroon suggesting that,instead of a unique nationwide control approach,a regionally adapted strategy will be needed to control this vector.The localised distribution of the F1534C kdr mutation supports this region-specific control strategy.