Background:Arboviral disease transmitted by Aedes albopictus such as dengue fever is an important threat to human health.Pyrethroid resistance raises a great challenge for mosquito control.A systematic assessment of A...Background:Arboviral disease transmitted by Aedes albopictus such as dengue fever is an important threat to human health.Pyrethroid resistance raises a great challenge for mosquito control.A systematic assessment of Ae.albopictus resistance status in China is urgently needed,and the study of correlation between pyrethroid resistance and knockdown resistance(kdr)mutations would provide information to guide the control of the Ae.albopictus vector.Methods:Five field populations of Ae.albopictus were collected from Jinan(JN),Hangzhou(HZ),Baoshan(BS),Yangpu(YP)and Haikou(HK),China in 2017.Insecticide-impregnated papers were prepared with four pyrethroid chemicals,deltamethrin,permethrin,beta-cypermethrin and lambda-cyhalothrin.The susceptibility of Ae.albopictus to pyrethroids was tested by the WHO tube assay.Kdr mutations were identified by PCR and sequencing.Moreover,the correlation analysis between kdr alleles and pyrethroid resistance was performed.Results:All five populations of Ae.albopictus showed resistance to four pyrethroid insecticides.One kdr mutant allele at codon 1532 and three at 1534 were detected with frequency of 5.33%(I1532T),44.20%(F1534S),1.83%(F1534 L)and 0.87%(F1534C),respectively.Both 1532 and 1534 mutation mosquitoes were found in the BS and YP populations.Allele I1532T was negatively correlated with deltamethrin resistance phenotype(OR<1),while F1534S mutation was positively correlated with deltamethrin and permethrin resistance(OR>1).Conclusions:The five field populations of Ae.albopictus adults were all resistant to deltamethrin,permethrin,betacypermethrin and lambda-cyhalothrin.Mutant F1534S was clearly associated with pyrethroid resistance phenotype in Ae.albopictus and this could be developed as a molecular marker to monitor the pyrethroid resistance problem in China.展开更多
Mosquitoes belonging to the genus Aedes pose a significant threat to human health on a global scenario due to their role in transmission of dengue,chikungunya,zika,and yellow fever.In absence of specific medications a...Mosquitoes belonging to the genus Aedes pose a significant threat to human health on a global scenario due to their role in transmission of dengue,chikungunya,zika,and yellow fever.In absence of specific medications and vaccines against these diseases,disease prevention relies on vector control.However,in today’s world,vector control is facing major challenges due to the onset of insecticide resistance in mosquitoes.There are four main mechanisms of insecticide resistance,namely,behavioral resistance,reduced penetration/cuticular resistance,metabolic detoxification,and target site resistance;however,the latter two mechanisms have been studied widely in Aedes mosquitoes.Insecticide resistance in Aedes mosquitoes is widespread throughout the world.This review compiles the degree of insecticide resistance/susceptibility prevailing among different field populations of Aedes mosquitoes worldwide.In addition,the review has detailed the mechanisms providing the resistance phenomenon observed in nature in Aedes mosquitoes.展开更多
Background:In the Republic of Congo,with two massive outbreaks of chikungunya observed this decade,little is known about the insecticide resistance profile of the two major arbovirus vectors Aedes aegypti and Aedes al...Background:In the Republic of Congo,with two massive outbreaks of chikungunya observed this decade,little is known about the insecticide resistance profile of the two major arbovirus vectors Aedes aegypti and Aedes albopictus.Here,we established the resistance profile of both species to insecticides and explored the resistance mechanisms to help Congo to better prepare for future outbreaks.Methods:Immature stages o f Ae.aegypti and Ae.albopictus were sampled in May 2017 in eight cities of the Republic of the Congo and reared to adult stage.Larval and adult bioassays,and synergist(piperonyl butoxide[PBO])assays were carried out according to WHO guidelines.F1534C mutation was genotyped in field collected adults in both species and the polymorphism of the sodium channel gene assessed in Ae.oegypti.Results:All tested populations were susceptible to temephos after larval bioassays.A high resistance level was observed to 4%DDT in both species countrywide(21.9-88.3% mortality).All but one population(Ae.oegypti from Ngo)exhibited resistance to type I pyrethroid,permethrin,but showed a full susceptibility to type II pyrethroid(deltamethrin)in almost all locations.Resistance was also reported to 1% propoxur in Ae.aegypti likewise in two Ae.albopictus populations(Owando and Ouesso),and the remaining were fully susceptible.All populations of both species were fully susceptible to 1%fenitrothion.A full recovery of susceptibility was observed in Ae.oegypti and Ae.albopictus when pre-exposed to PBO and then to propoxur and permethrin respectively.The F1534C kdr mutation was not detected in either species.The high genetic variability of the portion of sodium channel spanning the F1534C in Ae.aegypti further supported that knockdown resistance probably play no role in the permethrin resistance.Conclusions:Our study showed that both Aedes species were susceptible to organophosphates(temephos and fenitrothion),while for other insecticide classes tested the profile of resistance vary according to the population origin.These findings could help to implement better and efficient strategies to control these species in the Congo in the advent of future arbovirus outbreaks.展开更多
Background:Dengue(DENV),chikungunya(CHIKV)and Zika virus(ZIKV),are mosquito-borne viruses of medical importance in most tropical and subtropical regions.Vector control,primarily through insecticides,remains the primar...Background:Dengue(DENV),chikungunya(CHIKV)and Zika virus(ZIKV),are mosquito-borne viruses of medical importance in most tropical and subtropical regions.Vector control,primarily through insecticides,remains the primary method to prevent their transmission.Here,we evaluated insecticide resistance profles and identifed important underlying resistance mechanisms in populations of Aedes aegypti and Ae.albopictus from six different regions in Cameroon to pesticides commonly used during military and civilian public health vector control operations.Methods:Aedes mosquitoes were sampled as larvae or pupae between August 2020 and July 2021 in six locations across Cameroon and reared until the next generation,G1.Ae.aegypti and Ae.albopictus adults from G1 were tested following World Health Organization(WHO)recommendations and Ae.aegypti GO adults screened with real time melting curve qPCR analyses to genotype the F1534C,V1016l and V410L Aedes kdr mutations.Piperonyl butoxide(PBO)assays and real time qPCR were carried out from some cytochrome p450 genes known to be involved in metabolic resistance.Statistical analyses were performed using Chi-square test and generalized linear models.Results:Loss of susceptibility was observed to all insecticides tested.Mortality rates from tests with 0.25%permethrin varied from 24.27%to 85.89%in Ae.aegypti and from 17.35%to 68.08%in Ae.albopictus.Mortality rates for 0.03%deltamethrin were between 23.30%and 88.20%in Ae.aegypti and between 69.47%and 84.11%in Ae.albopictus.We found a moderate level of resistance against bendiocarb,with mortality rates ranging from 69.31%to 90.26%in Ae.aegypti and from 86.75%to 98.95%in Ae.albopictus.With PBO pre-exposure,we found partial or fully restored suscepti bility to pyrethroids and bendiocarb.The genes Cyp9M6F88/87 and Cyp9J10 were overexpressed in Ae.aegypti populations from Douala sites resistant to permethrin and deltamethrin.Cyp6P12 was highly expressed in alphacypermethrin and permethrin resistant Ae.albopictus samples.F1534C and V1016l mutations were detected in A.aegypti mosquitoes and for the first time V410L was reported in Cameroon.Conclusions:This study revealed that Ae.aegypti and Ae albopictus are resistant to multiple insecticide classes with multiple resistance mechanisms implicated.These findings could guide insecticide use to control arbovirus vectors in Cameroon.展开更多
基金This work was supported by National Natural Sciences Foundation of China(No.81371848)the Infective Diseases Prevention and Cure Project of China(No.2017ZX10303404–002).
文摘Background:Arboviral disease transmitted by Aedes albopictus such as dengue fever is an important threat to human health.Pyrethroid resistance raises a great challenge for mosquito control.A systematic assessment of Ae.albopictus resistance status in China is urgently needed,and the study of correlation between pyrethroid resistance and knockdown resistance(kdr)mutations would provide information to guide the control of the Ae.albopictus vector.Methods:Five field populations of Ae.albopictus were collected from Jinan(JN),Hangzhou(HZ),Baoshan(BS),Yangpu(YP)and Haikou(HK),China in 2017.Insecticide-impregnated papers were prepared with four pyrethroid chemicals,deltamethrin,permethrin,beta-cypermethrin and lambda-cyhalothrin.The susceptibility of Ae.albopictus to pyrethroids was tested by the WHO tube assay.Kdr mutations were identified by PCR and sequencing.Moreover,the correlation analysis between kdr alleles and pyrethroid resistance was performed.Results:All five populations of Ae.albopictus showed resistance to four pyrethroid insecticides.One kdr mutant allele at codon 1532 and three at 1534 were detected with frequency of 5.33%(I1532T),44.20%(F1534S),1.83%(F1534 L)and 0.87%(F1534C),respectively.Both 1532 and 1534 mutation mosquitoes were found in the BS and YP populations.Allele I1532T was negatively correlated with deltamethrin resistance phenotype(OR<1),while F1534S mutation was positively correlated with deltamethrin and permethrin resistance(OR>1).Conclusions:The five field populations of Ae.albopictus adults were all resistant to deltamethrin,permethrin,betacypermethrin and lambda-cyhalothrin.Mutant F1534S was clearly associated with pyrethroid resistance phenotype in Ae.albopictus and this could be developed as a molecular marker to monitor the pyrethroid resistance problem in China.
基金University Grants Commission,New Delhi,India for providing financial assistance throughout this work through Junior Research Fellowship[award letter Sr.No.2121430414,Ref No.21/12/2014(ii)EU-V,Dated 03/06/2015]
文摘Mosquitoes belonging to the genus Aedes pose a significant threat to human health on a global scenario due to their role in transmission of dengue,chikungunya,zika,and yellow fever.In absence of specific medications and vaccines against these diseases,disease prevention relies on vector control.However,in today’s world,vector control is facing major challenges due to the onset of insecticide resistance in mosquitoes.There are four main mechanisms of insecticide resistance,namely,behavioral resistance,reduced penetration/cuticular resistance,metabolic detoxification,and target site resistance;however,the latter two mechanisms have been studied widely in Aedes mosquitoes.Insecticide resistance in Aedes mosquitoes is widespread throughout the world.This review compiles the degree of insecticide resistance/susceptibility prevailing among different field populations of Aedes mosquitoes worldwide.In addition,the review has detailed the mechanisms providing the resistance phenomenon observed in nature in Aedes mosquitoes.
文摘Background:In the Republic of Congo,with two massive outbreaks of chikungunya observed this decade,little is known about the insecticide resistance profile of the two major arbovirus vectors Aedes aegypti and Aedes albopictus.Here,we established the resistance profile of both species to insecticides and explored the resistance mechanisms to help Congo to better prepare for future outbreaks.Methods:Immature stages o f Ae.aegypti and Ae.albopictus were sampled in May 2017 in eight cities of the Republic of the Congo and reared to adult stage.Larval and adult bioassays,and synergist(piperonyl butoxide[PBO])assays were carried out according to WHO guidelines.F1534C mutation was genotyped in field collected adults in both species and the polymorphism of the sodium channel gene assessed in Ae.oegypti.Results:All tested populations were susceptible to temephos after larval bioassays.A high resistance level was observed to 4%DDT in both species countrywide(21.9-88.3% mortality).All but one population(Ae.oegypti from Ngo)exhibited resistance to type I pyrethroid,permethrin,but showed a full susceptibility to type II pyrethroid(deltamethrin)in almost all locations.Resistance was also reported to 1% propoxur in Ae.aegypti likewise in two Ae.albopictus populations(Owando and Ouesso),and the remaining were fully susceptible.All populations of both species were fully susceptible to 1%fenitrothion.A full recovery of susceptibility was observed in Ae.oegypti and Ae.albopictus when pre-exposed to PBO and then to propoxur and permethrin respectively.The F1534C kdr mutation was not detected in either species.The high genetic variability of the portion of sodium channel spanning the F1534C in Ae.aegypti further supported that knockdown resistance probably play no role in the permethrin resistance.Conclusions:Our study showed that both Aedes species were susceptible to organophosphates(temephos and fenitrothion),while for other insecticide classes tested the profile of resistance vary according to the population origin.These findings could help to implement better and efficient strategies to control these species in the Congo in the advent of future arbovirus outbreaks.
文摘Background:Dengue(DENV),chikungunya(CHIKV)and Zika virus(ZIKV),are mosquito-borne viruses of medical importance in most tropical and subtropical regions.Vector control,primarily through insecticides,remains the primary method to prevent their transmission.Here,we evaluated insecticide resistance profles and identifed important underlying resistance mechanisms in populations of Aedes aegypti and Ae.albopictus from six different regions in Cameroon to pesticides commonly used during military and civilian public health vector control operations.Methods:Aedes mosquitoes were sampled as larvae or pupae between August 2020 and July 2021 in six locations across Cameroon and reared until the next generation,G1.Ae.aegypti and Ae.albopictus adults from G1 were tested following World Health Organization(WHO)recommendations and Ae.aegypti GO adults screened with real time melting curve qPCR analyses to genotype the F1534C,V1016l and V410L Aedes kdr mutations.Piperonyl butoxide(PBO)assays and real time qPCR were carried out from some cytochrome p450 genes known to be involved in metabolic resistance.Statistical analyses were performed using Chi-square test and generalized linear models.Results:Loss of susceptibility was observed to all insecticides tested.Mortality rates from tests with 0.25%permethrin varied from 24.27%to 85.89%in Ae.aegypti and from 17.35%to 68.08%in Ae.albopictus.Mortality rates for 0.03%deltamethrin were between 23.30%and 88.20%in Ae.aegypti and between 69.47%and 84.11%in Ae.albopictus.We found a moderate level of resistance against bendiocarb,with mortality rates ranging from 69.31%to 90.26%in Ae.aegypti and from 86.75%to 98.95%in Ae.albopictus.With PBO pre-exposure,we found partial or fully restored suscepti bility to pyrethroids and bendiocarb.The genes Cyp9M6F88/87 and Cyp9J10 were overexpressed in Ae.aegypti populations from Douala sites resistant to permethrin and deltamethrin.Cyp6P12 was highly expressed in alphacypermethrin and permethrin resistant Ae.albopictus samples.F1534C and V1016l mutations were detected in A.aegypti mosquitoes and for the first time V410L was reported in Cameroon.Conclusions:This study revealed that Ae.aegypti and Ae albopictus are resistant to multiple insecticide classes with multiple resistance mechanisms implicated.These findings could guide insecticide use to control arbovirus vectors in Cameroon.
