Susceptibility to temephos,permethrin and deltamethrin of Aedes aegypti(Diptera:Culicidae) from Muang district,Phitsanulok Province,Thailand

Objective:To investigate the susceptibility to temephos.permethrin and deltamethrin of Aedes aegypti Ae.aegypti),collected from areas with high incidence of dengue hemorrhagic fever cases in Phitsanulok Province.Thailand.Methods:The F1 progenies of Ae.aegypti colony,originated from five sub-districts including Aranyik.Hua Ro,Nai Muang.Ban Krang and Tha Pho,were used in the bioassays following the procedures of World Heath Organization.For larval bioassay.the late third or early fourth-instar lanae were tested with different concentrations of temephos.For adult bioassay.the females were exposed to 0.75%permethrin or 0.05%deltamethrin.LC_(50)value and mortality rate were analyzed to compare the insecticide susceptibility of the larvae and the adults in each area,respectively.Results:The LC_(50) value of temephos for the larvae from Aranyik.Hua Ro.Nai Muang,Ban Krang and Tha Pho sub-districts was 0.017.0.017.0.026.0.061.and 0.113 ppm,respectively.For permethrin,the highest morlalitv rate(86.84%) was found in the mosquitoes from Aranyik but the others were more resistant with the lower morlality rates(16.00-42.67%).The adult morlality rates after exposing to dellaiiielhrin were higher(82.34-98.67%) in all areas.Conclusions:Ae.acgypti larvae were still susceptible to temephos.Conversely,most tested adults tended to resist the penmethrin and deltamethrin.

Comparative susceptibility to permethrin of two Anopheles gambiae s.l.populations from Southern Benin,regarding mosquito sex,physiological status,and mosquito age

Objective:To investigate what kind of mosquito sample is necessary for the determination of insecticide susceptibility in malaria vectors.Methods:Larvae and pupae of Anopheles gambiae s.l.(An.gambiae)mosquitoes were collected from the breeding sites in Littoral and Oueme departments.The Centers for Disease Control and Prevention(CDC)susceptibility tests were conducted on unfed male and female mosquitoes aged 2-5 days old.CDC susceptibility tests were also conducted on unfed,blood fed and gravid female mosquitoes aged2-5 days old.These susceptibility tests were also conducted on unfed and blood fed female mosquitoes aged 2-5 days old and 20 days old.CDC biochemical assay using synergist was also carried out to detect any increase in the activity of enzyme typically involved in insecticide metabolism.Results:Female An,gambiae Ladji and Sekandji populations were more susceptible than the males when they were unfed and aged 2-5 days old.The mortality rates of blood fed female An.gambiae Ladji and Sekandji populations aged 2-5 days old were lower than those obtained when females were unfed.In addition,the mortality rales of gravid female An.gambiae Ladji and Sekandji populations aged2-5 days old were lower than those obtained when they were unfed.The mortality rate obtained when female An.gambiae Sekandji populations were unfed and aged 20 days old was higher than the one obtained when these populations were unfed and aged 2-5 days old.The results obtained after effects of synergist penicillin in beeswax on F1 progeny of An.gambiae Ladji populations resistant to permethrin showed that mono-oxygenases were involved in permethrin resistant F1 progeny from Ladji.Conclusions:The resistance is a hereditary and dynamic phenomenon which can be due to metabolic mechanisms like overproduction of detoxifying enzymes activity.Many factors influence vector susceptibility to insecticide.Among these factors,there are mosquito sex,mosquito age,its physiological status.Therefore,it is useful to respect the World Health Organization criteria in the assessment of insecticide susceptibility tests in malaria vectors.Otherwise,susceptibility testing is conducted using unfed female mosquitoes aged 3-5 days old.Tests should also be carried out at(25±2)°C and(80±10)%relative humidity.

Changes in Myelinated Nerve Fibers and Skeletal Muscle of Rats Exposed to High Doses of Permethrin

Neurological signs and segmcntal demyelination in a cervical nerve were observed in rats treated orally with permethrin (300 mg/kg/day) for 5 days. Inflammatory and degenerative signals were recorded in the diaphragm muscle. These effects were more intense with the trade grade than with the technical grade product. The possible influence of the percentage of cisitrans isomers on the intensity of the observed effects is discussed. 5 imi Academic Press.Inc.

防虫蛀纯羊毛绒线中Permethrin残留量的GC/MS测定

毛绒织物样品以 1∶1丙酮—正己烷混合溶剂超声提取后 ,提取液经Celite层析柱净化 ,40℃旋转蒸发浓缩、定容 ,由色—质联用仪测定试样中的氯菊酯 (Permethrin)含量。本方法对目标化合物的检测限量在 0 1～0 5mg kg范围内 ,平均回收率介于 89 1%～ 10 1 2 %之间 ,相对标准偏差为 2 3%～ 4 4 %。

Evaluation of the Efficacy and Safety of 1%Sodium Chloride(LiceFreee Spray)against 1%Permethrin Creme Rinse on Head Lice Infested Individuals

Head lice are a public health issue, and resistance to available over-the-counter pediculicides is a concern. The objective of this randomized study was to evaluate the pediculicidal activity and safety of 1% Sodium Chloride spray (0.1709 M), (LiceFreee Spray&#174) compared to the current recommended treatment for head lice with 1% Permethrin Crème Rinse. Forty-two subjects were randomized equally into Sodium Chloride or Permethrin group. Products were applied to hair according to the label instructions. After application of the products at Day 1 and Day 8, pediculicidal efficacy and safety were assessed at Day 1, Day 8 and Day 15. Second treatment was only applied on Day 8 to individuals with observed live lice using the same products and protocols as Day 1. Proportion of lice free subjects per group, the reduction in number of live lice per head and adverse effects were recorded after each visit. The results showed significantly higher pediculicidal activity for Sodium Chloride spray (85%) as compared to Permethrin (45%) at Day 15 (p 0.05). Similar numbers of lice per head (21.76 range 10 to 68 versus 21.29 range 10 to 60 for Sodium Chloride and Permethrin groups, respectively) were observed for individuals at Day 1. At Day 15, lice per head infested reduced to 0.55 ± 1.50 in Sodium Chloride spray group compared to 5.45 ± 7.91 in the Permethrin group (p 0.01). No serious adverse effects were observed in both groups. Sodium Chloride spray had superior efficacy to 1% Permethrin Crème Rinse in treating head lice and is a safe and excellent alternative to the current recommended treatment.

Molecular and functional characterization of three novel carboxylesterases in the detoxification of permethrin in the mosquito, Culex quinquefasciatus

Carboxylesterases (CarEs) belong to a super family of multifunctional enzymes associated with the degradation of endogenous and exogenous compounds. Many insect CarEs are known to play important roles in catalyzing the hydrolysis of organophosphates (OPs), carbamates, and synthetic pyrethroids (SPs). The elevation of esterase activity through gene amplification and overexpression of estα2 and estβ2 genes contributes to the development of resistance to OP insecticides in the mosquito Culex quinquefasciatus. Three additional CarE genes are upregulated in permethrin-resistant Cx. quinquefasciatus according to an RNA-seq analysis, but their function remains unknown. In this study, we, for the first time, characterized the function of these three novel genes using in vitro protein expression, an insecticide metabolism study and molecular docking analysis. All three CarE genes were significantly overexpressed in resistant mosquito larvae, but not adults, compared to susceptible strain. No gene copy differences in these three genes were found in the mosquitoes tested. In vitro high-performance liquid chromatography (HPLC) revealed that CPIJ018231, CPIJ018232, and CPIJ018233 metabolized 30.4% ± 2.9%, 34.7% ± 6.8%, and 23.2% ± 2.2% of the permethrin, respectively. No mutations in resistant strains might significantly affect their CarE hydrolysis ability. A docking analysis further confirmed that these three CarEs from resistant strain all potentially metabolize permethrin. Taken together, these three carboxylesterase genes could play important roles in the development of permethrin resistance in Cx. quinquefasciatus larvae through transcriptional overexpression, metabolism, and detoxification.

Dynamics and mechanisms of permethrin resistance in a field population of the horn fly, Haematobia irritans irritans

A study was conducted at the Pressler ranch, near Kerrville, Texas, USA between 2002 and 2006 to determine the dynamics and mechanisms of resistance to permethrin in a field population of the horn fly, Haematobia irritans irritans （L.）. Changes of resistance to pyrethroid insecticide associated with use of a pour-on formulation of cyfluthrin in 2002 and use of diazinon ear tags in subsequent years were studied using a filter paper bioassay technique and a polymerase chain reaction assay that detects two sodium channel mutations, kdr and super-kdr resistance alleles. A maximum of 294-fold resistance to permethrin was observed in the summer of 2002. A significant decrease in the resistance level was observed in spring 2003, and resistance continued to decline after animals were treated with diazinon ear tags. In response to pyrethroid treatments, the allelic kdr and super-kdr frequency increased from 56.3% to 93.8% and from 7.5% to 43.8%, respectively in 2002, and decreased significantly in 2003 when the pyrethroid insecticide was no longer used to treat animals. Females were found to have a higher allelic super-kdr frequency than males in 2002, while no difference was detected between males and females in the allelic kdr frequency. There was a significant positive correlation between frequencies of the sodium channel mutations and levels ofpermethrin resistance, suggesting that the sodium channel mutations, kdr and super-kdr, are the major mechanisms of resistance to pyrethroids in this horn fly population. Results of synergist bioassays also indicated possible contributions of two metabolic detoxification mechanisms, the mixed function oxidases （MFO） and glutathione S-trans- ferases （GST）. Compared to a horn fly infestation of an untreated herd, treatments with the pyrethroid pour-on formulation failed to control horn flies at the Pressler ranch in 2002. Sustained control of horn flies was achieved with the use of diazinon ear tags in 2003 and subsequent years.

Permethrin resistance variation and susceptible reference line isolation in a field population of the mosquito, Culex quinquefasciatus （Diptera： Culicidae）

This study examines the genetic variations and mechanisms involved in the development of permethrin resistance in individual mosquitoes from a field population of Culex quinquefasciatus, HAmCq^G0, and characterizes susceptible reference lines of mosquitoes with a similar genetic background to the field HAmCq^G0 strain. Six upregulated cytochrome P450 genes, CYP9M10, CYP9J34, CYP6P14, CYP9J40, CYP6AA7, and CYP4C52v1, previously identified as being upregulated in the larvae of resistant HAmCq68 mosquitoes were examined in the larvae of 3 strains （susceptible S-Lab, parental HAmCq^G0 and permethrin-selected highly resistant HAmCq68） and 8 HAmCq^G0 single- egg raft colonies, covering a range of levels of susceptibility/resistance to perrnethrin and exhibiting different variations in the expression of A and/or T alleles at the L-to-F kdr locus of the sodium channel. The 2 lines with the lowest tolerance to permethrin and bearing solely the susceptible A allele at the L-to-F kdr locus of the sodium channels, from colonies Cx_SERC5 and Cx_SERC8, showed lower or similar levels of all 6 of the P450 genes tested compared with the S-Lab strain, suggesting that these 2 lines could be used as the reference mosquitoes in future studies characterizing insecticide resistance in HAmCq mosquitoes. This study also provides a detailed investigation of the mechanisms involved in insecticide resistance in individuals within a population： individuals with elevated levels of resistance to permethrin all displayed one or more potential resistance mechanisms-either elevated levels of P450 gene expression, or L-to-F mutations in the sodium channel, or both.

Bioefcacy and durability of Olyset® Plus, a permethrin and piperonyl butoxide-treated insecticidal net in a 3-year long trial in Kenya

Background:Long-lasting insecticide nets(LLINs)are a core malaria intervention.LLINs should retain efficacy against mosquito vectors for a minimum of three years.Efficacy and durability of Olyset®Plus,a permethrin and piperonyl butoxide(PBO)treated LLIN,was evaluated versus permethrin treated Olyset®Net.In the absence of WHO guidelines of how to evaluate PBO nets,and considering the manufacturer’s product claim,Olyset®Plus was evaluated as a pyrethroid LLIN.Methods:This was a household randomized controlled trial in a malaria endemic rice cultivation zone of Kirinyaga County,Kenya between 2014 and 2017.Cone bioassays and tunnel tests were done against Anopheles gambiae Kisumu.The chemical content,fabric integrity and LLIN survivorship were monitored.Comparisons between nets were tested for signifcance using the Chi-square test.Exact binomial distribution with 95%confdence intervals(95%CI)was used for percentages.The WHO efcacy criteria used were≥95%knockdown and/or≥80%mortality rate in cone bioassays and≥80%mortality and/or≥90%blood-feeding inhibition in tunnel tests.Results:At 36 months,Olyset®Plus lost 52%permethrin and 87%PBO content;Olyset®Net lost 24%permethrin.Over 80%of Olyset®Plus and Olyset®Net passed the WHO efcacy criteria for LLINs up to 18 and 12 months,respec‑tively.At month 36,91.2%Olyset®Plus and 86.4%Olyset®Net survived,while 72%and 63%developed at least one hole.The proportionate Hole Index(pHI)values representing nets in good,serviceable and torn condition were 49.6%,27.1%and 23.2%,respectively for Olyset®Plus,and 44.9%,32.8%and 22.2%,respectively for Olyset®Net but were not signifcantly diferent.Conclusions:Olyset®Plus retained efcacy above or close to the WHO efcacy criteria for about 2 years than Olyset®Net(1–1.5 years).Both nets did not meet the 3-year WHO efcacy criteria,and showed little attrition,comparable physical durability and survivorship,with 50%of Olyset®Plus having good and serviceable condition after 3 years.Better community education on appropriate use and upkeep of LLINs is essential to ensure efectiveness of LLIN based malaria interventions.

Effect of Particle Size and Pesticide Contamination on Preference and Ingestion Rates by the Tropical Freshwater Shrimp Xiphocaris elongata

In tropical streams, freshwater shrimp are essential to preserve the structure and function of lotic ecosystems. Shredder shrimp play a fundamental role in organic matter decomposition because these feed on detritus. In addition, they are especially important organisms as they connect all trophic levels at food webs. In natural environments, decaying leaf material may accumulate contaminants, including insecticides and herbicides. At these, shredder shrimp can be exposed to these contaminants through ingestion of leaf litter material. The objectives of this study were to evaluate if the shredder shrimp Xiphocaris elongata display a preference for feeding on different plant species and leaf size areas while also assessing their consumption of leaves contaminated with pesticides. We also evaluated acetylcholinesterase (AChE) activity as a possible biomarker of pesticide contamination using an immunofluorescence and microscopy imaging approach. Our results revealed that the leaf area and plant species more appropriate for future toxicological studies is Spathodea campanulata leaves, with a leaf area of 0.65 cm2. This study also showed that sublethal concentrations of malathion and permethrin in leaves seem to have a significant effect on the ingestion rates of X. elongata, which suggests that the presence of these contaminants influenced feeding behavior. Immunofluorescence in cephalothorax ganglia showed a decline in AChE activity when the sublethal dose of malathion and permethrin increased. The observed results suggest that AChE activity can be used as a biomarker to detect and assess permethrin and malathion exposure on shredder shrimp.

富黏液质果蔬中氯菊酯残留量的测定

为改进气相色谱法测定富黏液质果蔬中氯菊酯残留量的分析方法,采用固相分散-超声提取技术使样品均匀分散在固态干燥剂基质中,利用有机溶剂与基质不相溶、易分离的特点,实现氯菊酯组分的有效提取,再经弗罗里硅土柱净化,气相色谱法测定。结果表明,在0.50~10.00μg·mL^(-1)线性良好(R=0.9995),方法检出限为0.0152~0.0242 mg·kg^(-1),加标回收率为83.34%~101.03%,CV值为5.11%,方法准确、可靠。

二氯苯醚菊酯传统致畸试验研究进展

二氯苯醚菊酯是一种高效低毒杀虫剂。传统致畸试验可以观察二氯苯醚菊酯对母体子宫内的胚胎或胎儿产生的作用,从而评价二氯苯醚菊酯的胚胎毒性及致畸性。通过对二氯苯醚菊酯的传统致畸试验等方面的研究文献进行归纳分析,以期为二氯苯醚菊酯生殖毒性的进一步研究提供理论参考。

海口市白纹伊蚊对菊酯类杀虫剂的抗药性及击倒抗性基因突变分析

目的了解海口市白纹伊蚊对溴氰菊酯和氯菊酯的抗药性,并检测其击倒抗性(kdr)基因突变型,阐明抗性表型与kdr基因突变的关系。方法在海口新埠岛、龙塘镇、石山镇、白沙门和花卉市场采集白纹伊蚊幼虫,应用浸渍法测定其对溴氰菊酯和氯菊酯杀虫剂的敏感性,以抗性倍数确定抗性级别。对应生物测定的样品扩增和分析白纹伊蚊的kdr基因部分片段,采用χ2检验比较抗性表型与kdr突变基因型的差异性。结果海口白纹伊蚊花卉市场和白沙门群体对溴氰菊酯和氯菊酯均产生抗性,花卉市场群体对溴氰菊酯的抗性倍数高达436.36,为高度抗性。龙塘镇和石山镇群体对氯菊酯均为敏感,对溴氰菊酯的抗性为低度(9.09)或中度(18.18)。新埠岛群体对溴氰菊酯和氯菊酯均为敏感。在对应检测的317只白纹伊蚊的kdr基因中,发现1 534位点存在点突变,检测到2种突变等位基因(TGC/C、TCC/S)。5种基因型和频率分别为野生型TTC/TTC(62.15%)、野生/突变型杂合子TTC/TGC(0.63%)和TTC/TCC(16.09%)、突变型纯合子TCC/TCC(20.82%)以及突变型杂合子TGC/TCC(0.32%)。χ2检验结果显示,接触菊酯类杀虫剂后敏感表型与抗性表型个体中,kdr基因型间的差异有统计学意义(P<0.05),在抗性表型群体中的kdr突变型基因型的频率(42.94%)大于敏感表型个体(31.97%)。结论海口市白纹伊蚊多个群体对溴氰菊酯和氯菊酯同时存在抗性,抗性表型与kdr突变基因型密切相关。本研究首次记录了kdr新的等位基因TCC/S。

红外光谱测定β-CD-氯菊酯包合物主-客体比的研究

氯菊酯 (P)是目前我国茶园允许使用的拟除虫菊酯仿生农药品种之一 ,有见光易分解的特点 ,将其制成环糊精包合物 (IC) ,可以增加其稳定性 ,从而减少用量、减少在茶叶等作物上残留量。包合比是包合物加工的重要参数之一。作者用饱和水溶液法制备了 β 环糊精 (CD) 氯菊酯包合物 ,并对其进行了红外光谱分析。结果显示主、客体各吸收峰的位置和强度均不因形成包合物而改变。首次用红外内标法测得 β CD 氯菊酯的包合比为 1∶1。所选内标物质为硫氰化钾 ,因为它仅在 2 10 0cm- 1 处有一个强吸收峰 ,以该峰为硫氰化钾的定量峰。以 5 80cm- 1 处 β CD的环振动特征吸收 ,为 β CD的定量峰。将硫氰化钾与 β CD以一定的质量比混合 ,进行红外光谱分析 ,建立内标工作曲线。为超分子主。

7种驱避剂驱蚊效果实验观察

目的 :实验观察 7种驱避剂驱蚊效果。方法 :将标准驱避剂避蚊胺与氯菊酯和高分子聚合物缓释剂相结合 ,研制成PD -Ⅰ、PD -Ⅱ、PD -Ⅲ型长效驱避剂 ,在实验室对白纹伊蚊进行驱避效果试验 ,与Deet原油及 3种市售驱避剂的驱避效果比较。结果 :人体按 1.5 μl/cm2 或 1.5mg/cm2 处理 ,PD型驱避剂对白纹伊蚊的平均有效驱避时间达 10～ 11h ,使用 12h后的有效保护率分别为 92 .3%、91.2 %和 88.3% ,优于其它 3种驱避剂和Deet原油。结论 :PD型驱避剂使用方便 ,无油腻感 ,效果较好。

棉铃虫对菊酯类杀虫剂抗药性的神经电生理研究

本文用神经电生理方法研究了氰戊菊酯、氯菊酯对棉铃虫Helicoverpaarmigera（Hubner）相对敏感（HD－S）种群和抗性（HJ－R）种群的神经毒理作用。10－5mol／L的氰戊菊酯、10－5mol／L，的氯菊酯诱发腹神经索自发发放频率的增加和随后的神经传导阻断，10-4mol／L的氯菊酯抑制HD－S种群的神经兴奋，直接阻断神经传导。以兴奋时间、神经传导阻断时间、对药剂作用反应时间的个体分布频率3个参数比较两种群对杀虫剂的反应，均发现HJ－R种群比相对HD-S种群表现了2～3倍的神经不敏感机制，并且发现这种神经不敏感机制对毒理Ⅰ型和Ⅱ型拟除虫菊酯同样有作用。

淡色库蚊氯菊酯抗性相关基因PR-OP全长cDNA的克隆及生物信息学分析

【目的】克隆淡色库蚊氯菊酯抗性相关视蛋白基因,并进行生物信息学分析,为阐明视蛋白基因的抗性机制及研制新型卫生杀虫剂奠定基础。【方法】依据库蚊抗性与敏感品系差异表达的EST片段设计PCR引物,采用RACE技术克隆淡色库蚊氯菊酯抗性相关基因PR-OP全长cDNA序列,并对其生物信息学进行分析。【结果】获得了长度为1 402 bp的淡色库蚊氯菊酯抗性相关基因PR-OP全长cDNA,其编码383个氨基酸。生物信息学分析结果表明,该基因编码蛋白为具有7个跨膜螺旋的膜蛋白,其保守域与视紫红质家族的保守域一致,该蛋白还具有2个信号肽切割位点和18个磷酸化位点。系统进化分析表明,该基因与淡色库蚊溴氰菊酯抗性相关视蛋白基因及致倦库蚊、埃及伊蚊视紫红质基因氨基酸序列同源性在69%以上,与家蚕、烟草天蛾、柞蚕、柑橘凤蝶、中华蜜蜂、黑腹果蝇视蛋白的氨基酸序列同源性均在56%以上。【结论】克隆了淡色库蚊氯菊酯抗性相关视蛋白基因(GenBank登录号为FJ917744),推测其与氯菊酯抗性相关。

珠江河网水产品中菊酯类农药残留调查及健康风险评价

2012年8月在珠江河网采集水产品样品(13种鱼,4种虾和2种贝),采用超声波提取-气相色谱法对样品中菊酯类农药(PYRs)进行残留检测,并对鱼类PYRs暴露水平进行健康风险评价。结果显示,鱼类肌肉、虾类和贝类中PYRs质量分数分别介于ND^3.05μg·kg-1、0.05~1.13μg·kg-1和0.69~1.20μg·kg-1(ND为未检出,以湿重计),平均值分别为0.90μg·kg-1、0.41μg·kg-1和0.99μg·kg-1。虾类和贝类中PYRs的检出率均很高,除联苯菊酯在虾类体内检出率为75%外,其他菊酯均为100%,鱼类肌肉中氯菊酯检出率最高,达到100%。氯菊酯在鱼类肌肉和贝类中的检出量最高,分别占总菊酯质量分数的52.2%和55.4%,溴氰菊酯在虾类中检出量最高,分别占总菊酯质量分数的33.0%;对居民通过食物摄入的PYRs进行食用暴露风险评估,结果表明,珠江河网水产品中PYRs人体健康危害的年总风险评价介于3.96×10-13~1.21×10-10a-1,水产品的安全消费量为5.54×104kg·d-1,水产品中的PYRs的健康危险风险很小。

取代苯甲醛肟羧酸酯的合成及生物活性研究──Ⅰ.取代苯甲醛肟二氯菊酸酯的合成及生物活性

探讨了α-取代苯甲醛肟合成的新方法，合成了20种新型菊酸肟酯类化合物，并对其进行了初步生物活性测试，化合物5a，5f具有很好的抗病毒活性．

玉米中氯氰菊酯、溴氰菊酯SPE净化及不确定度分析

应用SPE净化代替GB/T5009.146-2003的传统净化法,并对其玉米中氯氰菊酯、溴氰菊酯测定数据的不确定度进行了分析。研究结果表明:用15mL石油醚/乙酸乙酯(体积比95∶5)淋洗氯氰菊酯和溴氰菊酯的回收率最高,分别达到了102.07%和80.86%,且在0.005～1mg/L之间具有0.995以上相关性。通过对应用SPE测定的不确定分析,氯氰菊酯和溴氰菊酯都具有较小的不确定度,分别为1.86%和1.91%,其不确定的主要来源为标准溶液的配制和样品的称量、定容。