Impact of Urban Agriculture on the Species Distribution and Insecticide Resistance Profile of <i>Anopheles gambiae s.s.</i>and <i>Anopheles coluzzii</i>in Accra Metropolis, Ghana

Malaria incidence in urban areas has generally been low compared to rural areas but recent data indicate that urban malaria remains a public health problem. It is therefore important to understand the factors that promote urban malaria to help formulate future vector control strategies. This study compared Anopheles gambiae s.l. (A. gambiae s.l.) species composition, distribution and insecticide resistance mechanisms between vegetable and non-vegetable growing areas in Accra Metropolis. Four sites were selected within the city of Accra which comprised of two vegetable-growing and two non-vegetable growing areas. WHO susceptibility tests were carried out on adults A. gambiae s.l. reared from larvae collected from the sites. Five insecticides were tested and the A. gambiae complex, resistance genotypes and enzyme activities of each population were characterized. All A. gambiae s.l. populations tested were resistant to all the insecticides, but relatively lower mortalities were observed in the vegetable growing areas. The mortality against 0.05% deltamethrin was 2.6% (Opeibea) and 12.5% (Korle-Bu) for the vegetable growing areas and 36.2% (Achimota) and 38.9% (Mataheko) in the non-vegetable growing areas. Anopheles gambiae s.s. (95% of Opeibea population) and Anopheles coluzzii, (98% of Korle-Bu population) were the dominant species in the vegetable growing areas. The voltage-gated sodium channel (Vgsc-1014F) frequencies of all the populations were similar but the acetylcholinesterase (ace-1) frequencies were significantly lower (p A. gambiae s.l. from Opeibea than from the other areas. The contribution of urban agriculture in the development of insecticide resistance needs to be considered in the formulation of future vector control strategies alongside other domestic usages.

Larvicidal activities of chinaberry,neem and Bacillus thuringiensis israelensis(Bti) to an insecticide resistant population of Anopheles arabiensis from Tolay,Southwest Ethiopia

Objective:To elucidate the larvicidal potency of neem, chinaberry and Bacillus thuringiensis israelensis(Bti) to larvae of Anopheles arabiensis under semi-field condition and adult susceptibility/resistance to the conventionally used insecticides in Tolay,Southwestern Ethiopia.Methods: Wild collected 3rd and 4th stage larvae were exposed to neem, and chinaberry seed powder dissolved in water and Bti in artificial containers at three treatment levels:0.2, 0.1 and 0.05 g/m^2 and controls were free of treatments. Larval and pupal mortalities were monitored daily and residual activities were determined. The experiments were replicated three times. The World Health Organization tube test for all classes of insecticides was conducted on adult Anopheles arabiensis reared from field collected larvae and pupae. Data were analyzed using STATA software version 11.Results: In the first application, neem powder caused 88.9%, 87.9% and 79.4% larval and pupal mortality at 0.2, 0.1 and 0.05 g/m^2 after 4.3, 6.0 and 5.7 days, respectively. The corresponding killing effect of chinaberry was 80.3%, 62.1% and 30.3% after 7.0, 7.7 and 8.3days respectively. Bti at all treatments killed 100% after 24 h except 2.7 days for 0.05 g/m^2.Adult mosquitoes were susceptible only for fenitrothion and pirimiphos-methyl with 100%mortality while resistant to deltamethrin, alpha-cypermethrin, etofenprox and dichlorodiphenyl-tricgloroethane with only 9.0%, 3.0%, 5.1% and 2.0% mortalities respectively.Conclusions: Neem, chinaberry and Bti showed potent larvicidal and pupicidal activities. However, in the area, high level of mosquito resistance to pyrethroids and dichlorodiphenyl-tricgloroethane was seen which will pose serious challenge to vector control in the future. Therefore, using integrated approach including these botanical larvicides is warranted to manage insecticide resistance.

Susceptibility of Anopheles maculipennis to different classes of insecticides in West Azarbaijan Province, Northwestern Iran

Objective: To determine the susceptibility status of Anopheles maculipennis(An. maculipennis) against the major insecticides used in the health sectors in West Azarbaijan Province, Northwestern Iran.Methods: Unfed 3-5 days old adult females of An. maculipennis were collected across the West Azarbaijan Province and were subjected to evaluation of their susceptibility following World Health Organization recommended protocol against six insecticides(permethrin, deltamethrin, propoxur, bendiocarb, malathion and dieldrin) belonging to four different classes. Results: In this study, 916 specimens of An. maculipennis were examined against the insecticides which indicated that An. maculipennis was tolerant to permethrin, deltamethrin and dielderin, but displayed resistance against propoxur, bendiocarb and malathion. Conclusions: The pattern of resistance in An. maculipennis could be attributed to the agricultural landscapes, agricultural pesticides used and the exposure of the mosquitoes to insecticides. Logical cooperation is needed between the agriculture and health sectors to ensure the judicious use of pesticides in each sector and the management of probable resistance.

Target-site mediated insecticide resistance in major mosquito(Diptera:Culicidae)vectors:A systematic review

The use of insecticides remain the most effective vector control approach for mosquito borne diseases like malaria,dengue fever,chikungunya,and Zika virus disease;however,their increasing resistance has complicated the management.Mutations in kdr,ace-1/ace-2,rdl,and nAChR,are involved in target-site mediated resistance and prevent the binding of pyrethroids and dichlorodiph enyltrichloroethane,organophosphorus pesticide,carbamates and cyclodienes,respectively.Here,we review the current knowledge on target-site mediated insecticidal resistance mechanisms in major mosquito vectors and the techniques used to identify these mutations.The results showed that kdr mutations are frequently reported in mosquito species,indicating the overuse of pyrethroid in mosquito control.Report on ace mutations is very limited,primarily detected in Anopheles and Culex,with extremely low detection rate in Aedes,despite the wide application of organophosphates in their control.Notably,reports of rdl mutations and changes in nAChR are rare,which provides an opportunity to exploit these target sites,particularly in the event of disease outbreaks.Among various detection methods such as RFLP,TaqMan,Multiplex PCR and FRET,allele-specific PCR is mostly employed,especially in detecting kdr mutation.However,allele-specific PCR cannot detect novel mutation.As a result,there is an urgent need to develop a scalable,cost-effective tool that can be widely applied especially as these mutations are genetic markers for early detection of insecticide resistance.Robust monitoring methods remain critical to manage insecticide resistance and effective control of mosquito-borne diseases.

Resistance status of main malaria vector, Liston (Diptera:Culicidae) to insecticides in a malaria Endemic Area,Southern Iran

Objective: To evaluate the susceptibility of Anopheles stephensi(An. stephensi) Liston, the main malaria vector in southern Iran, to WHO recommended insecticides. Methods: Larvae of An. stephensi were collected from three different larval habitats in both urban and rural area of Bandar Abbas city and one rural area in Rudan county southern Iran. WHO standard method was used for evaluation of adult and larval mosquito susceptibility. Bendiocarb, permethrin, lambda-cyhalothrin, deltamethrin as insecticide and temephos and chlorpyriphos as larvicide were used at the diagnostic dosages recommended by WHO. Results: Findings of this study showed all larval populations of An. stephensi were completely susceptible to temephos and candidate for resistance to chlorpyriphos. Adult mosquitoes in rural areas of Bandar Abbas city were resistant to pyrethroid and carbamate insecticides. Conclusion: Comparison of the results of this survey with previous studies indicates that the resistance to pyrethroids and carbamates in this malaria endemic region is increasing. Wide use of pesticides in agriculture is certainly effective in increasing resistance. The inter-sectoral coordination and collaboration in health and agriculture seem to be necessary to manage insecticide resistance in malaria vectors.

云南中华按蚊(An.sinensis)和微小按蚊(An.minimus)对五种杀虫剂的抗性调查

1992—1994年对云南省的思茅、景洪、潞西等20个县市、25个点的中华按蚊、微小按蚊对DDT、马拉硫磷(Malathion)、杀螟硫磷(Fenitrothion)、二氯苯醚菊酯(Permethrin)和溴氰菊酯(Deltamethrin)的抗性情况进行了调查,结果共获104个数据,中华按蚊对DDT显示出较高而普遍的抗性,对Permethrin和Deltamethrin分别有中度和高度抗性出现;整个调查结果以Malathion和Fenitrothion最敏感。

High insecticide resistance in the major malaria vector Anopheles coluzzii in Chad Republic

Background:The Sahel region of Chad Republic is a prime candidate for malaria pre-elimination.To facilitate preelimination efforts in this region,two populations o f A nopheles coluzzii from Central Chad Republic were characterized,their insecticide resistance profile and the possible molecular mechanisms driving the resistance in the field investigated.Methods:Bloodfed female Anopheles gom biae s.l.resting indoor,were collected at N'djamena and Massakory,Chad in 2018 and characterized for species composition,and infection rate was determined using the TaqMan assay.Susceptibility to various insecticides was assessed using WHO tube bioassays.Cone bioassays were conducted using various long-lasting insecticidal nets(LLINs).Results were analysed using Chi Square test.Knockdown resistance(kdr)and ace-1 markers were investigated by TaqMan genotyping.Results:Anopheles coluzzi was the major vector found in N’djamena(100%)and Massakory(〜94%).N〇Plasm odium was found in 147 bloodfed F0 An.coluzzii(82 from N'djamena and 65 from Massakory).High intensity pyrethroid resistance was observed with mortalities of<2%for permethrin,deltamethrin and etofenprox,and with<50%and<60%dead following exposure to 10x diagnostic doses of deltamethrin and permethrin,respectively.For both sites,<10%mortalities were observed with DDT.Synergist bioassays with piperonylbutoxide significantly recovered pyrethroid susceptibility in Massakory populations,implicating CYP450s(mortality=13.6%for permethrin,X^2=22.8,df=1,P=0.0006;mortality=13.0%for deltamethrin,x2:8.8,df=1,P<0.00031).Cone-bioassays established complete loss of efficacy of the pyrethroid-based LLINs;and a 100%recovery of susceptibility following exposure to the roof of PermaNet®3.0/containing piperonylbutoxide.Both populations were susceptible to malathion,but high bendiocarb resistance was observed in Massakory population.The absence o f a ce-1 mutation points to the role of metabolic resistance in the bendiocarb resistance.Both 1014F and 1014S mutations were found in both populations at around 60%and<20%respectively.Sequencing of intron-1 of the voltage-gated sodium channel revealed a low genetic diversity suggesting reduced polymorphism.Conclusions:Multiple resistance in An.coluzzii populations from Chad highlight challenges associated with deployment of LLINs and indoor residual spraying(IRS)in the Sahel of this country.The pyrethroid-synergists LLINs(e.g.PermaNet®3.0)and organophosphate-based IRS maybe the alternatives for malaria control in this region.

Efficacy of PermaNet^(■)3.0 and PermaNet^(■)2.0 nets against laboratory-reared and wild Anopheles gambiae sensu lato populations in northern Tanzania

Background:Mosquitoes have developed resistance against pyrethroids,the only class of insecticides approved for use on long-lasting insecticidal nets(LLINs).The present study sought to evaluate the efficacy of the pyrethroid synergist PermaNet^(■)3.0 LLIN versus the pyrethroid-only PermaNet^(■)2.0 LLIN,in an East African hut design in Lower Moshi,northern Tanzania.In this setting,resistance to pyrethroid insecticides has been identified in Anopheles gambiae mosquitoes.Methods:Standard World Health Organization bioefficacy evaluations were conducted in both laboratory and experimental huts.Experimental hut evaluations were conducted in an area where there was presence of a population of highly pyrethroid-resistant An.arabiensis mosquitoes.All nets used were subjected to cone bioassays and then to experimental hut trials.Mosquito mortality,blood-feeding inhibition and personal protection rate were compared between untreated nets,unwashed LLINs and LLINs that were washed 20 times.Results:Both washed and unwashed PermaNet^(■)2.0 and PermaNet^(■)3.0 LLINs had knockdown and mortality rates of 100%against a susceptible strain of An.gambiae sensu stricto.The adjusted mortality rate of the wild mosquito population after use of the unwashed PermaNet^(■)3.0 and PermaNet^(■)2.0 nets was found to be higher than after use of the washed PermaNet^(■)2.0 and PermaNet^(■)3.0 nets.Conclusions:Given the increasing incidence of pyrethroid resistance in An.gambiae mosquitoes in Tanzania,we recommend that consideration is given to its distribution in areas with pyrethroid-resistant malaria vectors within the framework of a national insecticide-resistance management plan.

Evidence of insecticide resistance selection in wildmosquitoes due to agricultural pesticide use

Background:The wetlands used for some agricultural activities constitute productive breeding sites for many mosquito species.Thus,the agricultural use of insecticide targeting other pests may select for insecticide resistance in malaria mosquitoes.The purpose of this study is to clarify some knowledge gaps on the role of agrochemicals in the development of insecticide resistance in malaria vectors is of utmost importance for vector control.Methods:Using the CDC bottle test and the log-probit analysis,we investigated for the first time the resistance levels ofAnopheles coluzzii mosquitoes to neonicotinoids,insecticides used exclusively for crop protection in C?te d’Ivoire.The study was conducted in two agricultural regions(Tiassale and Gagnoa)and one non-agricultural region(Vitre)between June and August 2017 using clothianidin,acetamiprid and imidacloprid.Results:Mosquito populations from Tiassale and Gagnoa(agricultural settings)were determined to be resistant to acetamiprid with mortality rates being<85%at 24 h post-exposure.In Vitre(non-agricultural area)however,the mosquito population was susceptible to acetamiprid.In all three localities,mosquito populations were resistant to imidacloprid(mortality rates were 60%in Vitre,37%in Tiassale,and 13%in Gagnoa)and completely susceptible to clothianidin(100%mortality).An.coluzzii represented 100%of mosquito collected in Gagnoa,86%in Tiassale and 96%in Vitre.Conclusions:This study provides strong evidence that agricultural use of insecticides can cause insecticide resistance in malaria vector populations.Insecticide resistance driven by agrochemical usage should be considered when vector control strategies are developed.

江苏省传疟按蚊对菊酯类杀虫剂抗药性的监测

目的 了解连续多年采用菊酯类杀虫剂处理蚊帐灭蚊后媒介按蚊的抗性情况。方法 采用 WHO成蚊滤纸接触法 ,以全国蚊类抗性监测网提供的区分剂量法来判定抗性级别。结果 连续采用菊酯类杀虫剂处理蚊帐 5年以上地区的中华按蚊对溴氰菊酯和二氯苯醚菊酯均已产生初级抗性 ,5年以下地区中华按蚊对这两种杀虫剂尚未产生抗性 ;连续灭蚊 5年以上地区未捕获嗜人按蚊 ,5年以下地区嗜人按蚊对菊酯类杀虫剂仍较敏感。结论 嗜人按蚊对溴氰菊酯和二氯苯醚菊酯尚未产生抗性 ,中华按蚊虽已产生抗性 ,但抗性水平仍较低 。

蚊虫抗药性监测研究

目的探讨辽宁省不同地区淡色库蚊和中华按蚊的抗药性状况,以期合理使用杀虫剂。方法采用浸渍法测定淡色库蚊和中华按蚊幼虫的LC50。结果各地试虫对3种杀虫剂的敏感性有差异:对溴氰菊酯,采自盘锦的蚊虫较敏感,采自朝阳、阜新的蚊虫已产生初步抗性,采自营口的蚊虫属实际抗药性,采自丹东的蚊虫有较强的抗性;对DDVP,采自盘锦市的蚊虫属初步抗性,而阜新和营口、朝阳市淡色库蚊、丹东市的中华按蚊则处于较高抗性水平;对高效氯氰菊酯,采自丹东的蚊虫有较强的抗性,与抗性最低者的敏感性相差10.6倍。结论抗药性的产生与杀虫药的使用情况有关,不同地区对药物应区别使用,以避免产生抗药性。

致倦库蚊及大劣按蚊对拟除虫菊酯类杀虫剂的抗药性测定

目的掌握海南省致倦库蚊和大劣按蚊对拟除虫菊酯类杀虫剂的抗药性发生及发展趋势。方法采用幼虫浸渍法,测定其对拟除虫菊酯类杀虫剂的抗性倍数。结果五指山市、澄迈县和海口市的致倦库蚊对溴氰菊酯抗性倍数分别为7.50、6.67、8.00倍,对氟氯氰菊酯的抗性倍数分别为5.31、6.00、6.23倍;琼中县大劣按蚊对溴氰菊酯和氟氯氰菊酯的抗性倍数分别为1.12和1.31倍。结论海南省致倦库蚊对这2种拟除虫菊酯类杀虫剂均产生了低抗药性;而大劣按蚊尚未产生。

嗜人按蚊分布区媒介按蚊对溴氰菊酯敏感性的监测

目的 :了解溴氰菊酯浸帐灭蚊多年后 ,嗜人按蚊和中华按蚊的敏感性。方法 :采用WHO成蚊滤纸接触法 ,以区分剂量来判定抗性级别 ,以LT50 来确定抗性程度。结果 :嗜人按蚊 :WHO区分剂量标准 ,死亡率 1 0 0 % ;我国区分剂量标准 ,死亡率 >80 %。中华按蚊 :WHO区分剂量标准 ,死亡率 >90 % ;我国区分剂量标准 ,死亡率 <80 %。浸帐灭蚊 1～ 2年、 3～ 5年和 6年的地区 ,嗜人按蚊LT50 分别为 8 6 9min、7 4 8mim (6年地区未采集到嗜人按蚊 ) ,中华按蚊LT50 分别为 1 1 98min、 1 5 38min、 1 6 2 7min。结论 :嗜人按蚊对溴氰菊酯尚未产生抗性。中华按蚊虽已产生抗性 ,但抗性程度不高 。

湖北部分地区疟疾媒介对DDT和溴氰菊酯抗药性的现场调查

为了解疟疾媒介对DDT和溴氰菊酯抗药性，为制定防制策略提供科学依据。采用WHO成蚊滤纸接触法，以区分剂量判定抗性级别，以半数致死量确定抗性程度。结果显示湖北京山、安陆、孝昌、仙桃和恩施等地媒介按蚊对DDT区分剂量死亡率均〈80％，LC50均〉4％，为高抗群体，与1993年调查一致；其KT50分别为1718．63、343．73、624．45、515．42和176．86min，具有很强的抗击倒力。溴氰菊酯区分剂量死亡率均〈80％，KT50分别为227．78、138．41、263．41、6234．72和1575．88min，比1996年分别提高29、17、37、532和212倍；京山县呱。684．12min，比1998年提高306倍。现场调查结果表明DDT停用多年后抗药性未明显下降，是否可重新用作室内滞留喷洒，需要进一步研究探讨；溴氰菊酯抗性发展迅猛，应加强监测，现场应用适当加大使用剂量，确保防制效果。

嗜人按蚊溴氰菊酯抗性分子机理研究 Ⅰ 嗜人按蚊CYP6基因cDNA片段的克隆与序列分析

目的获得嗜人按蚊CYP6基因家族成员的cDNA片断。方法采用简并引物对嗜人按蚊溴氰菊酯敏感和抗性品系总RNA进行RT-PCR扩增,得到的特异性片断采用T/A克隆法克隆并进行序列测定和分析。结果敏感品系和抗性品系中均扩增得到250bp左右的片断。进行克隆测序,得到10个CYP6新基因,2个来自敏感品系,8个来自抗性品系,被GenBank收录(登录号AY273927～AY273936)。递交国际细胞色素P450命名委员会,被鉴定为是细胞色素P450超家族中CYP6家族的7个新基因及其3个等位基因,分别属于CYP6Z、CYP6P、CYP6N和CYP6M等4个亚家族。结论得到的10个cDNA新序列为CYP6家族新成员的基因片断。

湖北省疟疾高发区媒介按蚊对杀虫剂敏感性的监测

[目的 ]了解采取不同灭蚊措施后 ,嗜人按蚊和中华按蚊对溴氰菊酯和 DDT的敏感性。 [方法 ]采用WHO成蚊滤纸接触法 ,观察蚊虫死亡率。 [结果 ]溴氰菊酯浸帐灭蚊 1年、3年和 DDT滞留喷洒灭蚊 3年的地区 ,嗜人按蚊对溴氰菊酯区分剂量死亡率分别为 83.8% ,83.7%和 84.7% ,为初步抗性群体 ,L T5 0 分别为 8.6 9,7.48和9.87min;中华按蚊对溴氰菊酯区分剂量死亡率分别为 76 .5 % ,5 7.0 %和 79.0 % ,为抗性群体 ,L T5 0 分别为 12 .0 ,15 .4和 11.2 m in;DDT喷洒地区嗜人按蚊对 DDT区分剂量死亡率为 95 .8% ,为初步抗性群体 ,L C5 0 为 0 .73% ;中华按蚊对 DDT区分剂量死亡率为 44 % ,为高抗群体 ,L C5 0 >4%。[结论 ]大量地在稻田使用杀虫剂 ,导致中华按蚊对溴氰菊酯和 DDT已产生抗药性 ,尚未发现嗜人按蚊产生明显抗药性。

嗜人按蚊溴氰菊酯抗性分子机理研究 Ⅲ 嗜人按蚊P450基因mRNA荧光半定量RT-PCR分析

目的探讨嗜人按蚊CYP6、CYP4基因与溴氰菊酯抗性的关系。方法采用荧光定量 RT-PCR方法,对嗜人按蚊体内CYP6和CYP4基因的mRNA进行半定量检测分析。结果嗜人按蚊抗性品系中CYP6基因mRNA的含量约为敏感品系的1．39倍。抗性品系中CYP4基因mRNA 的含量约为敏感品系的3．63倍。结论嗜人按蚊抗性品系体内的CYP6和CYP4的mRNA量高于其敏感品系,提示嗜人按蚊溴氰菊酯产生抗性机理可能与其细胞色素P450表达量增高有关。

河南信阳中华按蚊对3种杀虫剂的敏感性调查

目的了解信阳地区主要传疟媒介中华按蚊药物敏感性状况,为制定防治策略提供依据。方法WHO推荐的成蚊滤纸接触筒法,用溴氰菊酯（0.05%）、DDT（4%）、马拉硫磷（5%）3种药纸对中华按蚊雌性成蚊进行测试。结果信阳9县区中华按蚊对溴氰菊酯、DDT、马拉硫磷的死亡率（或校正死亡率）范围分别为22.22%~100%、11.11%~100%、25.33%~100%;不同县区中华按蚊对同一杀虫剂的抗性级别均有从敏感群体（S）到抗性群体（R）的分布;9县区中华按蚊对溴氰菊酯、DDT的首只击倒时间范围为1.0~23.78min、0.5~53.67 min,60 min击倒率范围为3.92%~75%、3.96%~95.05%,KT50范围为42.02~1 459.54min、35.23~1 459.54 min。结论信阳地区9县区中华按蚊对3种杀虫剂敏感性不全相同,存在地域差异。

嗜人按蚊溴氰菊酯抗性分子机理研究Ⅱ嗜人按蚊CYP4基因cDNA片段的克隆与序列分析

目的 获得嗜人按蚊CYP4基因家族成员的c DNA片段。方法 采用简并引物对嗜人按蚊溴氰菊酯敏感和抗性品系总RNA进行RT- PCR扩增,得到的特异性片段采用T/ A克隆法克隆并进行序列测定和分析。结果 敏感品系和抗性品系嗜人按蚊均能扩增得到4 5 0 bp和5 30 bp左右的2个片段。经克隆测序后,得到6个基因序列,其中4个来自敏感品系,2个来自抗性品系。其中1个来自敏感品系的序列和1个来自抗性品系的序列完全相同。所得的5个不同基因序列已被Gen Bank收录(登录号:AY2 0 814 1～AY2 0 814 5 ) ,并递交国际细胞色素P4 5 0命名委员会,经鉴定确认均为细胞色素P4 5 0超家族中的CYP4家族成员,其中4个为新基因,另1个为等位基因,分别属于CYP4家族的CYP4 C、CYP4 H和CYP4 J3个亚家族。结论 得到的5个c DNA新序列为CYP4家族新成员的基因片段。

中缅边境地区云南省沧源县中华按蚊对常用杀虫剂抗性及突变情况调查

目的助力云南省消除疟疾后防止输入再传播工作。为选择或更换适宜的杀虫剂,控制当地媒介按蚊提供科学依据。方法在中缅边境地区云南省沧源县开展传疟媒介中华按蚊对常用杀虫剂抗药性和抗性基因突变调查,选定沧源县勐董镇勐董社区芒勐寨旁永和下7组为监测点,使用吸蚊管于试验前夜在现场采集牛圈内的中华按蚊成蚊,带回实验室饲以10%葡萄糖水供试验用。参照《蚊虫抗药性检测方法生物测定法》(GB/T26347-2010),采用成蚊接触筒法开展中华按蚊对常用杀虫剂的抗药性监测调查。测定结束后分别收集死亡(敏感表型)和存活(抗性表型)个体,用无水乙醇保存带回,提取蚊DNA后,开展抗药性靶标kdr(knockdown resistance)、ace-1基因突变检测。结果接触0.05%高效氯氰菊酯、0.05%高效氯氟氰菊酯、0.05%溴氰菊酯、0.1%残杀威、5%马拉硫磷和1%杀螟硫磷后,中华按蚊首只被击倒的时间分别为5 min 34 s、5 min 11 s、6 min 46 s、4 min 30 s、5 min 13 s和3 min 36 s;击倒率分别为17.49%、17.32%、15.44%、29.72%、57.39%和46.82%。其中,中华按蚊对溴氰菊酯首只击倒时间最长,击倒率最低,表明对溴氰菊酯的抗击倒力最强,其次为高效氯氟氰菊酯和高效氯氰菊酯。中华按蚊对马拉硫磷区分剂量死亡率是98.33%,为敏感群体(S),对杀螟硫磷区分剂量死亡率是90%,为初步抗性群体(M),对高效氯氰菊酯、高效氯氟氰菊酯、溴氰菊酯和残杀威区分剂量死亡率均小于80%,为抗性群体(R)。检测接触拟除虫菊酯类杀虫剂的中华按蚊共386只,kdr基因的1014位点全部为L1014野生型,未检测到突变;检测接触有机磷和氨基甲酸酯的中华按蚊113只,仅存在G119S型突变。中华按蚊ace-1的119位点突变与氨基甲酸酯类杀虫剂抗性相关。结论当地传疟媒介中华按蚊对高效氯氰菊酯等拟除虫菊酯类杀虫剂和残杀威已产生较大抗药性,为防止输入性疟疾引起再传播,今后宜选用马拉硫磷等有机磷类或不同类别杀虫剂联合制剂开展媒介控制工作。