Knockdown resistance gene mutations of Aedes albopictus from Fuzhou and Putian, Fujian, 2020
Objective To understand the mutations of knockdown resistance ( kdr) gene of Aedes albopictus in dengue fever surveillance sites in Fuzhou and Putian. Methods From May to June in 2020, Aedes albopictus larvae were collected from Fuzhou (Jin’an District, Yongtai County) and Putian (Hanjiang District and Xianyou County), and then reared and reproduced in lab. DNA was extracted from each single female mosquito of F 1 generation after the exposure tubes method on adults. Using PCR to amplify partial fragments of the voltage-gated sodium channel (VGSC) gene on the nerve cell membrane. The mutations in the kdr gene were analyzed by sequencing. Results A total of 491 Aedes albopictus were detected in Fuzhou and Putian, in which no mutation was found in domain II or at I1532 locus in domain III, but there were mutations at F1534 locus in domain III of the VGSC gene. There were four alleles at the F1534 locus, namely wild-type TTC/F (252, 25.66%), mutant TCC/S (722, 73.52%), mutant TGC/C (3, 0.31%), and mutant CTC/L (5, 0.51%); seven genotypes, i.e., the wild-type homozygote F/F (39, 7.94%), wild/mutant heterozygote F/C (1, 0.20%), F/S (172, 35.03%) and F/L (1, 0.20%), mutant heterozygote S/C (2, 0.41%) and S/L (4, 0.81%), and mutant homozygote S/S (272, 55.40%). Mutant allele TCC/S at F1534 locus was found in all four populations and the frequencies in Hanjiang and Xianyou were higher than those in Jin’an and Yongtai. There were five genotypes at F1534 locus in Jin’an and Yongtai, but only three genotypes in Hanjiang and Xianyou. Wild/mutant heterozygote F/S and mutant homozygote S/S were found in all four populations, but wild-type homozygote F/F was not found in Hanjiang. The main genotype in Jin’an and Yongtai was F/S, while that in Hanjiang and Xianyou was S/S. Conclusion The kdr gene mutation rate is high in Fuzhou and Putian and F1534S is the main mutation type. This suggests that we should pay close attention to the resistance level of local mosquitos, reduce the use of pyrethroid insecticides, and use insecticides scientifically and rationally. 摘要: 目的 了解福州市和莆田市登革热伊蚊监测点白纹伊蚊击倒抗性基因的突变情况。 方法 2020 年 5—6 月在福州市(晋安区、永泰县)和莆田市 (涵江区、仙游县) 采集白纹伊蚊幼虫, 饲养繁殖, 使用成蚊接触筒法实验结束 的F 1代单只雌蚊样本, 提取 DNA, PCR 扩增电压门控钠离子通道 (VGSC) 基因部分片段, 测序分析击倒抗性 (knockdown resistance, kdr) 基因突变情况。 结果 福州市和莆田市共检测 491 只白纹伊蚊, 其中 VGSC 基因第 II 结构域及第 III 结构域的 I1532 位点未发现突变位点, 第 III 结构域的 F1534 位点存在突变。F1534 位点有 4 种等位基因, 即野生型 TTC/F(252,25.66%)、突变型 TCC/S(722, 73.52%)、TGC/C(3, 0.31%) 和 CTC/L(5, 0.51%); 7 种基因型, 分别为野生型 纯合子 F/F (39,7.94%), 野生/突变型杂合子 F/C (1,0.20%)、F/S (172,35.03%) 和 F/L (1, 0.20%), 突变型杂合子 S/C (2,0.41%) 和 S/L (4,0.81%), 突变型纯合子 S/S (272,55.40%)。F1534 位点突变等位基因 TCC/S 在 4 个种群中均有发现, 且莆田市涵江区和仙游县的频率髙于福州市晋安区和永泰县的频率。晋安区和永泰县 F1534 位点存在 5 种基因型, 涵江区和仙游县则只有 3 种。野生/突变型杂合子 F/S 和突变型纯合子 S/S 在 4 个种群中均存在, 野生型纯合子 F/F 只 在涵江区中没有发现。晋安区和永泰县基因型以 F/S 为主, 涵江区和仙游县以 S/S 为主。 结论 福州市和莆田市 kdr 基因突变频率髙, 以 F1534S 突变类型为主。提示应密切关注当地蚊虫抗性水平, 减少拟除虫菊酯类杀虫剂的使用, 科学合理地使用杀虫剂。
- Research Article
33
- 10.1186/s13071-019-3829-5
- Dec 1, 2019
- Parasites & Vectors
BackgroundMutation of the voltage-gated sodium channel (VGSC) gene, or knockdown resistance (kdr) gene, is an important resistance mechanism against DDT and pyrethroids for dengue vector Aedes albopictus. A phenylalanine to serine (F1534S), leucine (F1534L) and cysteine (F1534C) substitution were detected in many Ae. albopictus populations around the world, and the mutant allele frequencies have been increasing in recent years. Therefore, it is essential to establish a simple, time-saving and cost-effective procedure to monitor the alleles in large-scale studies.MethodsBased on the mutation genotypes of the 1534 locus in the kdr gene, F/F, F/S, F/C, F/L, S/S, C/C, L/L and S/C, we designed specific forward and reverse primers and optimized the reaction conditions for establishing of the allele-specific PCR(AS-PCR) detection technique. DNA sequencing in this study was taken as the gold standard, and used to determine the accuracy of AS-PCR.ResultsThe designed AS-PCR technique showed high specificity for distinguishing the mutations at the 1534 locus, as the accuracy for F/F, F/S, F/C, F/L, S/S, C/C and S/C were 100%, 95.35%, 100%, 100%, 100%, 100% and 100%, respectively.ConclusionsThe designed AS-PCR technique effectively distinguished individual genotypes for the mutations at the 1534 locus in the kdr gene, which could facilitate the knockdown resistance surveillance in Ae. albopictus in large-scale studies.
- Research Article
116
- 10.1371/journal.pntd.0004696
- May 4, 2016
- PLoS Neglected Tropical Diseases
BackgroundAedes albopictus is an important dengue vector because of its aggressive biting behavior and rapid spread out of its native home range in Southeast Asia. Pyrethroids are widely used for adult mosquito control, and resistance to pyrethroids should be carefully monitored because vector control is the only effective method currently available to prevent dengue transmission. The voltage-gated sodium channel gene is the target site of pyrethroids, and mutations in this gene cause knockdown resistance (kdr). Previous studies reported various mutations in the voltage-gated sodium channel (VGSC) gene, but the spatial distribution of kdr mutations in Ae. albopictus has not been systematically examined, and the association between kdr mutation and phenotypic resistance has not been established.MethodsA total of 597 Ae. albopictus individuals from 12 populations across Asia, Africa, America and Europe were examined for mutations in the voltage-gated sodium channel gene. Three domains for a total of 1,107 bp were sequenced for every individual. Two populations from southern China were examined for pyrethroid resistance using the World Health Organization standard tube bioassay, and the association between kdr mutations and phenotypic resistance was tested.ResultsA total of 29 synonymous mutations were found across domain II, III and IV of the VGSC gene. Non-synonymous mutations in two codons of the VGSC gene were detected in 5 populations from 4 countries. A novel mutation at 1532 codon (I1532T) was found in Rome, Italy with a frequency of 19.7%. The second novel mutation at codon 1534 (F1534S) was detected in southern China and Florida, USA with a frequency ranging from 9.5–22.6%. The WHO insecticide susceptibility bioassay found 90.1% and 96.1% mortality in the two populations from southern China, suggesting resistance and probable resistance. Positive association between kdr mutations with deltamethrin resistance was established in these two populations.ConclusionsTwo novel kdr mutations, I1532T and F1534S were found in Ae. albopictus. This is the first report of I1532T mutations in Italy and F1534S mutation in China and US. Significant association between kdr mutation and protection from deltamethrin raised the possibility that kdr mutation may be a viable biomarker for pyrethroid resistance surveillance in Ae. albopictus. The patchy distribution of kdr mutations in Ae. albopictus mosquitoes calls for developing global surveillance plan for pyrethroid resistance and developing countermeasures to mitigate the spread of resistance.
- Research Article
- 10.1186/s13071-026-07339-8
- Mar 31, 2026
- Parasites & vectors
Visceral leishmaniasis, caused by Leishmania donovani and transmitted by Phlebotomus argentipes, remains a major public health challenge in the Indian subcontinent. Sand fly populations are controlled by using different insecticides, particularly dichlorodiphenyltrichloroethane (DDT) and pyrethroids such as alpha-cypermethrin. Prolonged and irregular use of these insecticides raises concern about the development of resistance in sand fly populations. This study aimed to compare metabolic detoxification and knockdown resistance (kdr) mutations in Vgsc and ace-1 between nine sprayed (indoor residual spray, IRS) villages and one unsprayed (non-IRS) village in Muzaffarpur, Bihar, India. A total of 10 Ph.argentipes from each village were used for metabolic detoxification and 10-25 Ph.argentipes were used for target site insensitivity mutations. Homogenized Ph.argentipes aliquots were used for different enzymes activity and DNA was used for the sequence analysis of Vgsc and ace-1 genes to access the presence of kdr mutations. Biochemical assays revealed that levels of detoxification enzymes, including glutathione S-transferase (GST), esterase (PNPA), and cytochrome P450 monooxygenase, were elevated in IRS villages, suggesting localized metabolic resistance. Molecular screening of the voltage-gated sodium channel (Vgsc) gene revealed high frequencies of knockdown resistance (kdr) mutations at codon 1014, with serine (L1014S) (48.5%) being the most prevalent, followed by wild type leucine (L1014) (39.5%). No mutations were detected at codon 119 of the ace-1 gene, indicating the sensitivity to organophosphates in the sand fly population. The results suggested that continuous and repeated exposure to the synthetic pyrethroid may exert selective pressure, leading to early signs of resistance in Ph.argentipes, mediated through metabolic detoxification mechanisms and mutation in the kdr gene. These findings underscore the importance of ongoing resistance monitoring and the implementation of rotational insecticide strategies to support sustained efforts toward the elimination of visceral leishmaniasis.
- Research Article
1
- 10.16250/j.32.1374.2018285
- Apr 17, 2019
- Zhongguo xue xi chong bing fang zhi za zhi = Chinese journal of schistosomiasis control
To study the seasonal dynamics of Culex pipiens pallens and the distribution of knockdown resistance (kdr) gene related sodium channel gene polymorphism in Zichuan District, Zibo City, Shandong Province. Cx. pipiens pallens mosquitoes were collected in Zichuan District during the peak period of mosquito vector activity from 2017 to 2018. The DNA from Cx. pipiens pallens was extracted, and the genotypes and frequencies of kdr allele mutation were detected by polymerase chain reaction. Totally 830 mosquitoes belonging to six species, including Cx. pipiens pallens, Armigeres subalbatus, Aedes albopictus, Ae. vexans, Anopheles sinensis, and Cx. tritaeniorhchus were collected in this study. The number of Cx. pipiens pallens accounted for 83.13% in total, with the density of 12.32 per lamp per night. The annual density monitoring curve of Cx. pipiens pallens showed a bimodal trend, and the peaks were observed in June and September respectively. In this study, five kdr alleles were detected at the 1 014 locus of kdr gene, with TTA (75.71%), TTT (10.00%), CTA (5.71%), TCA (4.29%), and TTC (4.29%). Two nonsynonymous nucleotide mutations were detected at site 1 014 of kdr gene, namely leucine (L1014) mutated to phenylalanine (L1014F) and serine (L1014S). The kdr gene mutation frequency (%) of Cx. pipiens pallens in Luochun Town and Taihe Town was 10.53% and 40.63%, respectively, and the difference was statistically significant ( χ2 = 8.559, P = 0.003). Cx. pipiens pallens is the dominant mosquito species in Zichuan District. In addition, two novel mutations, CTA and TTC, are identified in the voltage-dependent sodium channel gene of Cx. pipiens pallens. The kdr genotype of Cx. pipiens pallens in Zichuan area was polymorphic.
- Research Article
21
- 10.1186/s12936-019-2834-7
- Jun 20, 2019
- Malaria journal
BackgroundMalaria remains an important public health problem in Latin America, and the development of insecticide resistance in malaria vectors poses a major threat to malaria elimination efforts. Monitoring of insecticide susceptibility and the determination of the mechanisms involved in insecticide resistance are needed to effectively guide the deployment of appropriate vector control measures. Here, molecular assays have been developed to screen for mutations associated with insecticide resistance on the voltage-gated sodium channel (VGSC) and acetylcholinesterase-1 (Ace-1) genes in four malaria vectors from Latin America.MethodsDegenerate primers were designed to amplify a partial fragment on the VGSC and Ace-1 genes. Wild-caught individuals for Anopheles albimanus (also historical samples and individuals from a laboratory strain), Anopheles darlingi, Anopheles vestitipennis and Anopheles pseudopunctipennis were used to optimize the PCR assays. All samples were sequenced to validate the PCR results and DNA alignments were constructed for each gene using the unique haplotypes observed.ResultsPrimers designed successfully amplified the VGSC gene in An. albimanus, An. darlingi, An. vestitipennis and An. pseudopunctipennis, and the Ace-1 gene in both An. albimanus and An. darlingi. DNA sequencing revealed that compared with Anopheles gambiae, there were a total of 29, 28, 21 and 24 single nucleotide polymorphisms (SNPs) on the VGSC gene for An. albimanus (308 bp), An. darlingi (311 bp), An. pseudopunctipennis (263 bp) and An. vestitipennis (254 bp), respectively. On the 459 bp fragment of the Ace-1 gene, a total of 70 SNPs were detected in An. darlingi and 59 SNPs were detected in An. albimanus compared with An. gambiae. The SNPs detected on the VGSC gene were all synonymous. On the Ace-1 gene, non-synonymous substitutions were identified on three different codons. All species showed the homozygous wild-type kdr allele (coding for leucine) at codon 995 (formerly reported as codon 1014) on the VGSC gene, but one sample was heterozygous at codon 280 (formerly reported as codon 119) on the Ace-1 gene, coding for both the resistant (serine) and susceptible (glycine) amino acids.ConclusionsNew molecular assays to amplify and screen the regions of the VGSC and Ace-1 genes associated with insecticide resistance are reported for An. albimanus, An. darlingi, An. vestitipennis, and An. pseudopunctipennis. The development of these PCR assays presents an important advance in the analysis of target-site resistance in malaria vectors in the Americas, and will further facilitate the characterization of insecticide resistance mechanisms in these species.
- Research Article
- 10.3389/fmicb.2026.1788609
- Apr 22, 2026
- Frontiers in microbiology
Aedes albopictus is the primary vector of major arboviral diseases such as dengue fever, chikungunya fever, and Zika virus disease, and its control is highly dependent on chemical insecticides. However, the long-term use of pyrethroid insecticides has led to the development of insecticide resistance in Ae. albopictus, which severely undermines the efficacy of vector control programs. Ae. albopictus populations were collected from five sites in Guangdong and Hainan provinces, China. Beta-cypermethrin resistance levels were determined via bioassays, with resistance ratios at the median lethal concentration (RR50) calculated. Target-site resistance was evaluated via kdr mutation detection in the voltage-gated sodium channel (VGSC) gene. Transcriptome sequencing identified differentially expressed genes (DEGs), and 16S rRNA sequencing characterized gut microbiome alterations. Correlation analysis and Cedecea neteri dietary supplementation assays verified the role of gut microbiota in resistance. The results showed that all four populations (except the CP population) exhibited varying degrees of resistance to beta-cypermethrin, with resistance ratios at the median lethal concentration (RR50) ranging from 2.84 to 29.18. Detection of kdr mutations revealed three mutations (F1534C, F1534L, F1534S) at codon 1534 of the voltage-gated sodium channel (VGSC) gene in all field populations, with mutation frequencies ranging from 49.4% to 100.0%, and a low-frequency V1016G mutation at codon 1016. Transcriptome analysis identified a total of 2,566 commonly upregulated genes and 994 commonly downregulated genes across the resistant populations. Gut microbiome analysis revealed a significant alteration in the intestinal microbial community structure of resistant populations; specifically, the relative abundance of the genus Cedecea differed significantly between resistant and susceptible populations and correlated strongly with the expression of most differentially expressed genes. Furthermore, dietary supplementation with Cedecea neteri significantly increased the survival rate of Ae. albopictus exposed to β-cypermethrin (73.86% vs 40.00%; P < 0.0001). From the perspectives of target-site mutations, gene expression regulation, and gut microbe interactions, this study providing a foundation for further studies on resistance mechanisms in Ae. albopictus, thereby providing a theoretical foundation for further dissection of resistance mechanisms and optimization of vector control strategies.
- Research Article
9
- 10.4269/ajtmh.19-0289
- Nov 6, 2019
- The American Journal of Tropical Medicine and Hygiene
Aedes mosquitoes are the principal dengue vector in Taiwan, where the use of insecticides is a key element in the national control strategy. However, control efforts are constrained by the development of resistance to most insecticides, including pyrethroids. In this study, mutations in the voltage-gated sodium channel (VGSC) gene resulting in knockdown resistance (kdr) were examined in Aedes aegypti. Fragments of the VGSC gene were polymerase chain reaction (PCR)-amplified followed by restriction fragment length polymorphism analysis in samples from various settings in Southern Taiwan covering dry and wet seasons from 2013 to 2015. Three kdr mutations were identified: V1023G, D1794Y, and F1534C, with observed frequencies of 0.36, 0.55, and 0.33, respectively, in the dry season of 2013-2014. Exploring for temporal changes, the most important observation was the 1534C allele frequency increment in the following season to 0.60 (P < 0.05). This study suggests that continued insecticide pressure is driving the mutational changes, although the selection is ambiguous in the mosquito population.
- Research Article
4
- 10.1186/s40249-023-01122-y
- Aug 15, 2023
- Infectious Diseases of Poverty
BackgroundThe current prevention and control strategy for Aedes albopictus heavily relies on comprehensive management, such as environmental management and chemical control. However, the wide application of pyrethroids has facilitated the development of insecticide resistance, primarily via mutations in the voltage-gated sodium channel (VGSC) gene. This study aims to develop a novel strategy for detecting mutations in the VGSC gene in Ae. albopictus using multiplex PCR-mass spectrometry (MPCR-MS) minisequencing technology.MethodsWe established a new strategy for detecting mutations in the VGSC gene in Ae. albopictus using MPCR-MS minisequencing technology. MPCR amplification and mass probe extension (MPE) were first used, followed by single nucleotide polymorphism (SNP) typing mass spectrometry, which allows the simultaneous detection of multiple mutation sites of the VGSC gene in 96 samples of Ae. albopictus. A total of 70 wild-collected Ae. albopictus were used to evaluate the performance of the method by comparing it with other methods.ResultsThree target sites (1016, 1532, 1534) in the VGSC gene can be detected simultaneously by double PCR amplification combined with matrix-assisted laser desorption ionization–time-of-flight mass spectrometry, achieving a detection limit of 20 fg/μl. We applied this method to 70 wild-collected Ae. albopictus, and the obtained genotypes were consistent with the routine sequencing results, suggesting the accuracy of our method.ConclusionsMPCR-MS minisequencing technology provides a sensitive and high-throughput approach to Ae. albopictus VGSC gene mutation screening. Compared with conventional sequencing, this method is economical and time-saving. It is of great value for insecticide resistance surveillance in areas with a high risk of vector-borne disease.Graphical
- Research Article
5
- 10.3390/genes14101892
- Sep 29, 2023
- Genes
Indoor residual spray (IRS), mainly employing pyrethroid insecticides, is the most common intervention for preventing malaria transmission in many regions of Latin America; the use of long-lasting insecticidal nets (LLINs) has been more limited. Knockdown resistance (kdr) is a well-characterized target-site resistance mechanism associated with pyrethroid and DDT resistance. Most mutations detected in acetylcholinesterase-1 (Ace-1) and voltage-gated sodium channel (VGSC) genes are non-synonymous, resulting in a change in amino acid, leading to the non-binding of the insecticide. In the present study, we analyzed target-site resistance in Nyssorhynchus darlingi, the primary malaria vector in the Amazon, in multiple malaria endemic localities. We screened 988 wild-caught specimens of Ny. darlingi from three localities in Amazonian Peru and four in Amazonian Brazil. Collections were conducted between 2014 and 2021. The criteria were Amazonian localities with a recent history as malaria hotspots, primary transmission by Ny. darlingi, and the use of both IRS and LLINs as interventions. Fragments of Ace-1 (456 bp) and VGSC (228 bp) were amplified, sequenced, and aligned with Ny. darlingi sequences available in GenBank. We detected only synonymous mutations in the frequently reported Ace-1 codon 280 known to confer resistance to organophosphates and carbamates, but detected three non-synonymous mutations in other regions of the gene. Similarly, no mutations linked to insecticide resistance were detected in the frequently reported codon (995) at the S6 segment of domain II of VGSC. The lack of genotypic detection of insecticide resistance mutations by sequencing the Ace-1 and VGSC genes from multiple Ny. darlingi populations in Brazil and Peru could be associated with low-intensity resistance, or possibly the main resistance mechanism is metabolic.
- Research Article
- 10.3389/fcimb.2026.1777964
- Mar 16, 2026
- Frontiers in Cellular and Infection Microbiology
IntroductionThe rapid evolution of insecticide resistance in mosquitoes has substantially compromised control efficacy against Aedes albopictus. This study aimed to evaluate the resistance levels to commonly used insecticides in field populations of Ae. albopictus from Hangzhou, China, and characterize knockdown resistance (kdr) mutations in the voltage-gated sodium channel (VGSC) gene, thereby providing a scientific basis for developing localized insecticide resistance management strategies.MethodsField populations of Ae. albopictus were collected from 14 districts in Hangzhou from May to September 2025. Resistance to 0.2% fenitrothion, 0.2% bendiocarb, 1.4% alpha-cypermethrin, 0.4% permethrin, and 0.7% beta-cyfluthrin was evaluated using the adult mosquito contact tube bioassays. Mutations in multiple kdr loci within VGSC domains and the G119 site of the ace-1 gene were detected by PCR amplification followed by Sanger sequencing.ResultsBioassays revealed that all field populations were resistant to permethrin (mortality: 2.67%–88.00%), and 86.7% of populations exhibited resistance or possible resistance to beta-cyfluthrin. However, all populations were susceptible to bendiocarb, and no confirmed resistance to fenitrothion was detected. Molecular analyses identified a high-frequency mutation exclusively at the F1534 locus of the VGSC gene (mutant TCC allele frequency: 89.23%). Significant variations in genotypic frequency distribution were observed among the districts (p < 0.001). Core urban districts (e.g., Gongshu and Yuhang) exhibited significantly higher kdr allele frequencies (>98%) and resistance levels compared with counties such as Fuyang and Lin’an.ConclusionAe. albopictus populations in Hangzhou exhibit widespread resistance to pyrethroid insecticides, which is spatially associated with a high frequency of the F1534S kdr mutation in the VGSC gene. The potential contribution of metabolic resistance, which may vary geographically, was not evaluated in this study. These findings suggest that resistance management strategies, including insecticide rotation and area-specific interventions, may be needed and should be informed by further investigation of local resistance mechanisms.
- Research Article
11
- 10.1371/journal.pntd.0011399
- Jun 2, 2023
- PLOS Neglected Tropical Diseases
Dengue fever is an infectious disease that is imported into Shanghai, China and requires prevention and control measures. Controlling the vector Aedes albopictus through insecticide use is a key approach to dengue control. However, the rapid evolution of insecticide resistance in Ae. albopictus has raised concerns about the failure of dengue control efforts. Knockdown resistance (kdr) caused by point mutations in the voltage-gated sodium channel (VGSC) gene is a primary mechanism of pyrethroid resistance. In this study, we investigated the kdr mutations of Ae. albopictus in Shanghai and evaluated the trend in its evolution. We collected 17 populations of Ae. albopictus from 15 districts in Shanghai in 2020, extracted genomic DNA from individual mosquitoes, and amplified Domain II, III, and IV in VGSC using PCR. Following sequencing, we obtained 658 VGSC sequences. We detected the nonsynonymous mutations V1016G, I1532T, and F1534S/C/I, among which V1016G and F1534C/I were reported in Shanghai for the first time and F1534I was a novel mutant allele in Ae. albopictus. The overall mutation frequency was 84.65%, with individual mutation frequencies ranging from 46.81% to 100%, excluding the Fengxian District population, which had a frequency of 0%. The V1016G and I1532T mutation types accounted for 7.14% and 3.42%, respectively. The mutant allele at codon 1534 accounted for 63.98% of all mutations, including TCC/S (62.77%), TGC/C (1.06%), and ATC/I (0.15%). We identified and classified five intron types in Domain III by length, including A (83 bp, 12.07%), B (68 bp, 87.30%), C (80 bp, 0.16%), D (72 bp, 0.16%), and E (70 bp, 0.31%). Individuals with intron B had a significant mutation tendency at codon 1534 relative to intron A (chi-square test, p < 0.0001). We found no correlation between mutation frequency and the amount of pyrethroid used (Pearson correlation, p = 0.4755). In recent years, kdr mutations in the Ae. albopictus population in Shanghai have rapidly evolved, as evidenced by an increase in mutation types and significantly increased mutation frequency. The F1534I/ATC mutant allele was found to be a novel mutation, F1534C/TGC was reported for the first time in Shanghai, and intron B in Domain III was significantly associated with mutation frequency at codon 1534. Continuous monitoring of resistance changes and strict regulation of insecticide use are required.
- Research Article
2
- 10.1371/journal.pone.0320200
- Mar 26, 2025
- PloS one
Dengue fever, transmitted by Aedes albopictus in China, is a major public health issue. The emergence of kdr gene mutations in Ae. albopictus has reduced the efficacy of insecticide-based control. We investigated the genetic structure of eight Ae. albopictus populations from China's southeastern coastal region, analyzing genetic diversity, population structure, and the prevalence of kdr mutations in relation to dengue fever incidence. Allelic diversity was moderate, with the number of alleles ranging from 2 to 6 and effective number of alleles from 1.52 to 5.00. Genetic clustering revealed four groups with 0.71% to 1.81% variation, indicating moderate differentiation. The coefficient of genetic differentiation value was 0.07 to 0.18, and Nm values 1.13 to 3.25. Except for Foshan and Sanming, four populations showed deltamethrin resistance, 4.31 to 18.87-fold. The voltage-gated sodium channel (VGSC) gene analysis identified non-synonymous mutations, with I1532 mutations absent in Sanming and F1534 present in all. Four populations showed resistance to deltamethrin, with resistance levels varying significantly. The VGSC gene analysis revealed multiple non-synonymous mutations associated with resistance, particularly at positions I1532 and F1534. No significant correlation was found between dengue fever incidence, kdr mutations, and genetic indicators, indicating a consistent potential for disease transmission. However, populations with higher genetic diversity had lower frequencies of F1534 and higher frequencies of I1532I mutations. The findings underscore the significant influence of kdr mutations on the effectiveness of mosquito control strategies. The presence of these mutations necessitates the implementation of alternative insecticides and integrated pest management approaches to sustainably reduce Ae. albopictus populations and mitigate the spread of dengue fever.
- Research Article
67
- 10.1002/ps.3880
- Sep 11, 2014
- Pest Management Science
Bed bugs [both Cimex hemipterus (F.) and Cimex lectularius L.] are highly resistant to pyrethroids worldwide. An important resistance mechanism known as 'knockdown resistance' (kdr) is caused by genetic point mutations on the voltage-gated sodium channel (VGSC) gene. Previous studies have identified two point mutations (V419L and L925I) on the VGSC gene in C. lectularius that are responsible for kdr-type resistance. However, the kdr mutations in C. hemipterus have not been investigated. Four novel mutations, L899V (leucine to valine), M918I (methionine to isoleucine), D953G (aspartic acid to glycine) and L1014F (leucine to phenylalanine), were identified in the domain II region of the C. hemipterus VGSC gene. This region has been widely investigated for the study of kdr-type resistance to pyrethroids in other insect pests. The V419L and L925I kdr mutations as previously identified in C. lectularius were not detected in C. hemipterus. M918I and L1014F are considered to be probable kdr mutations and may play essential roles in kdr-type resistance to pyrethroids in C. hemipterus. Further studies are under way in the authors' laboratory to determine the non-kdr-type resistance mechanisms in C. hemipterus.
- Research Article
- 10.1007/s00436-025-08538-5
- Jan 1, 2025
- Parasitology Research
Aedes aegypti (Linnaeus 1762) is a significant public health concern in both its native and invaded regions because of the transmission of arboviruses. Target-site mutations in the voltage-gated sodium channel (vgsc) gene, commonly referred to as knockdown resistance (kdr), represent the most extensively studied mechanism underlying pyrethroid resistance. Therefore, we aimed to assess possible pyrethroid and organochlorine resistance levels, knockdown resistance, and mutation types known to contribute to the resistance profile in the Black Sea region of Türkiye in 2020. Bioassay results showed that all field populations, as well as the Bora Bora laboratory strain, were susceptible and predominantly carried wild-type genotypes. For kdr, all samples were wild type for the V410L, L982W, S989P, I1011V/M, L1014F, V1016I/G, and T1520I mutations. The mutant allele was detected in only one specimen in the Pazar population, where it was found in a homozygous state at position F1534C from ten specimens. Novel mutations in the vgsc gene region, with unknown implications for resistance, were determined at positions A1498T, R1599C, P1611L, and P1615S in the studied populations. Two different intron types were detected in the kdr gene (in domain 2) between nucleotide positions 3111 and 3228 and within an intron region (coded as type-1 and type-2). These findings indicate that, Ae. aegypti populations in the Eastern Black Sea region remain susceptible to pyrethroid and organochlorine insecticides. Genetic analyses indicate that these populations likely originated from Asia, with evidence of two distinct lineages. Notably, this study represents the first molecular and phenotypic assessment of insecticide resistance in Ae. aegypti populations conducted in Türkiye.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00436-025-08538-5.
- Research Article
9
- 10.18502/ijph.v48i6.2916
- Jun 1, 2019
- Iranian Journal of Public Health
Background:Some mosquito species which belong to the Culex. pipiens complex are primary vectors for West Nile virus, Sindbis, Dirofilaria immitis, and many arboviruses. Knockdown resistance (kdr) mutations in the voltage-gated sodium channel (VGSC) gene of Cx. pipiens that is inherited, is one of the important threats for the efficacy of pyrethroids insecticides. Knockdown resistance (kdr) mutation, L1014F, is a well-defined mechanism of resistance to pyrethroids and DDT in many insect species. The aim of study was to determine the mechanisms of Insecticide resistance in this speciesMethods:Specimens of Cx. pipiens, the major vector of West Nile virus, were obtained in Tehran, Iran by collecting larvae from polluted wastewater in Qarchak of Tehran. In 2016 Insecticide susceptibility tests were performed according to WHO methods with deltamethrin 0.05%. We focused on determination of this point mutation in the VGSC gene of Cx. pipiens by Real-time PCR.Results:Our results revealed high levels of resistance to deltamethrin 0.05%. The lethal times i.e. LT50 and LT90 for deltamethrin were 2.1530 and 8.5117 h respectively. The result of Real-time PCR confirmed the presence of resistant genotype in all the members of tested population. This study is the first report on kdr genotyping of Cx. pipiens from Tehran and our results on the VGSC gene in position L1014F confirmed the TTA to TTT nucleotide change.Conclusion:This finding will provide a clue for management of insecticide resistance in mosquito which are vectors of arboviruses and decision for replacement of novel approach for vector control.