scholarly journals First Evidence of the Implication of Cuticular Based Mechanisms in Aedes Aegypti Populations Resistant To Pyrethroids and DDT in Cameroon

2021 ◽  
Author(s):  
Borel DJIAPPI TCHAMEN ◽  
Nana-Ndjangwo Stella Mariette ◽  
Vasileia Balabanidou ◽  
Konstantinos Mavridis ◽  
Makoudjou Idene ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Pyrethroid Resistance ◽  
Cuticular Hydrocarbon ◽  
Target Site ◽  
Detoxification Enzymes ◽  
The Difference ◽  
Susceptible Populations ◽  
Cuticular Resistance

Abstract Pyrethroid resistance is now expanding in the two main arboviruses vectors Aedes aegypti and Aedes albopictus from Cameroon. Although recent studies suggested the implication of target site (kdr) resistance and overexpression of detoxification enzymes as key mechanisms, the implication of additional mechanisms such as cuticular resistance has not been investigated. The present study assesses the possible implication of cuticle in Aedes species resistance to pyrethroids. High cuticular hydrocarbon (CHC) content was detected in Ae. aegypti populations from Douala and Yaoundé. The difference (38% increase) between the Douala and susceptible populations was found to be statistically significant.The study confirms the implication of cuticular-based mechanisms in resistant to pyrethroids and DDT Aedes aegypti mosquitoes from Cameroon.

scholarly journals Permethrin resistance in Aedes aegypti: Genomic variants that confer knockdown resistance, recovery, and death

PLoS Genetics ◽  
2021 ◽  
Vol 17 (6) ◽  
pp. e1009606
Author(s):  
Karla Saavedra-Rodriguez ◽  
Corey L. Campbell ◽  
Saul Lozano ◽  
Patricia Penilla-Navarro ◽  
Alma Lopez-Solis ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Pyrethroid Resistance ◽  
Disease Outbreaks ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Detoxification Enzymes ◽  
Nucleotide Polymorphisms ◽  
Knockdown Resistance ◽  
High Association ◽  
Genomic Markers

Pyrethroids are one of the few classes of insecticides available to control Aedes aegypti, the major vector of dengue, chikungunya, and Zika viruses. Unfortunately, evolving mechanisms of pyrethroid resistance in mosquito populations threaten our ability to control disease outbreaks. Two common pyrethroid resistance mechanisms occur in Ae. aegypti: 1) knockdown resistance, which involves amino acid substitutions at the pyrethroid target site—the voltage-gated sodium channel (VGSC)—and 2) enhanced metabolism by detoxification enzymes. When a heterogeneous population of mosquitoes is exposed to pyrethroids, different responses occur. During exposure, a proportion of mosquitoes exhibit immediate knockdown, whereas others are not knocked-down and are designated knockdown resistant (kdr). When these individuals are removed from the source of insecticide, the knocked-down mosquitoes can either remain in this status and lead to dead or recover within a few hours. The proportion of these phenotypic responses is dependent on the pyrethroid concentration and the genetic background of the population tested. In this study, we sequenced and performed pairwise genome comparisons between kdr, recovered, and dead phenotypes in a pyrethroid-resistant colony from Tapachula, Mexico. We identified single-nucleotide polymorphisms (SNPs) associated with each phenotype and identified genes that are likely associated with the mechanisms of pyrethroid resistance, including detoxification, the cuticle, and insecticide target sites. We identified high association between kdr and mutations at VGSC and moderate association with additional insecticide target site, detoxification, and cuticle protein coding genes. Recovery was associated with cuticle proteins, the voltage-dependent calcium channel, and a different group of detoxification genes. We provide a list of detoxification genes under directional selection in this field-resistant population. Their functional roles in pyrethroid metabolism and their potential uses as genomic markers of resistance require validation.

scholarly journals Mechanisms of Pyrethroid Resistance in the Dengue Mosquito Vector, Aedes aegypti: Target Site Insensitivity, Penetration, and Metabolism

2014 ◽  
Vol 8 (6) ◽  
pp. e2948 ◽  
Author(s):  
Shinji Kasai ◽  
Osamu Komagata ◽  
Kentaro Itokawa ◽  
Toshio Shono ◽  
Lee Ching Ng ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Pyrethroid Resistance ◽  
Target Site ◽  
Mosquito Vector

scholarly journals Insecticide resistance of Dengue vectors in South East Asia: a systematic review

2021 ◽  
Vol 21 (3) ◽  
pp. 1124-1140
Author(s):  
Mohd Rohaizat Hassan ◽  
Noor Atika Azit ◽  
Suhaiza Mohd Fadzil ◽  
Siti Rasidah Abd Ghani ◽  
Norfazilah Ahmad ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
East Asia ◽  
Aedes Albopictus ◽  
Pyrethroid Resistance ◽  
Resistance Management ◽  
Genetic Mutation ◽  
Peninsular Malaysia ◽  
South East Asia ◽  
Dengue Vectors

Background: The insecticides used widely has led to resistance in the vector and impose a challenge to vector control op- eration. Objectives: This review aims to analyse the distribution of insecticide resistance of dengue vectors in South East Asia and to describe the mechanism of insecticide resistance. Methods: Literature search for articles published on 2015 to 2019 from PubMed, Scopus and ProQuest was performed. Total of 37 studies included in the final review from the initial 420 studies. Results: Pyrethroid resistance was concentrated on the west coast of Peninsular Malaysia and Northern Thailand and scat- tered at Java Island, Indonesia while organophosphate resistance was seen across the Java Island (Indonesia), West Sumatera and North Peninsular Malaysia. Organochlorine resistance was seen in Sabah, Malaysia and scattered distribution in Nusa Tenggara, Indonesia. V1016G, S989P, F1269C gene mutation in Aedes Aegypti were associated with Pyrethroid resistance in Singapore and Indonesia. In Malaysia, over-expressed with monooxygenase P450 genes (CYP9J27, CYP6CB1, CYP9J26 and CYP9M4) Glutathione S-transferases, carboxylesterases commonly associated with pyrethroids resistance in Aedes Aegypti and CYP612 overexpressed in Aedes Albopictus. The genetic mutation in A302S in Aedes Albopictus was associated with organochlorine resistance in Malaysia. Conclusions: Rotation of insecticide, integration with synergist and routine assessment of resistance profile are recom- mended strategies in insecticide resistance management. Keywords: Insecticide resistance; vector management; Aedes; pyrethroid; mortality.

scholarly journals Quantification of permethrin resistance and kdr alleles in Florida strains of Aedes aegypti (L.) and Aedes albopictus (Skuse)

2018 ◽  
Author(s):  
Alden S. Estep ◽  
Neil D. Sanscrainte ◽  
Christy M. Waits ◽  
Sarah J. Bernard ◽  
Aaron M. Lloyd ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Sodium Channel ◽  
Genetic Markers ◽  
Aedes Albopictus ◽  
Topical Application ◽  
Pyrethroid Resistance ◽  
Management Program ◽  
Health Concern ◽  
Effective Control ◽  
Resistance Testing

AbstractRecent outbreaks of locally transmitted dengue and Zika viruses in Florida have placed more emphasis on the importance of integrated vector management plans for Aedes aegypti (L.) and Aedes albopictus Skuse. Adulticiding, primarily with pyrethroids, can be the best option available for the immediate control of potentially arbovirus-infected mosquitoes during outbreak situations. While pyrethroid resistance is common in Ae. aegypti worldwide and testing is recommended by CDC and WHO, resistance to this class of products has not been widely examined or quantified in Florida. To address this information gap, we performed the first study to quantify both pyrethroid resistance and genetic markers of pyrethroid resistance in Ae. aegypti and Ae. albopictus strains in Florida. Using direct topical application, we examined 21 Ae. aegypti strains from 9 counties and found permethrin resistance (resistance ratio (RR)=6-61-fold) in all strains when compared to the susceptible ORL1952 control strain. Permethrin resistance in five strains of Ae. albopictus was very low (RR<1.6) even when collected from the same containers producing resistant Ae. aegypti. Characterization of two sodium channel kdr alleles associated with pyrethroid-resistance showed widespread distribution in 62 strains of Ae. aegypti. The 1534 phenylalanine to cysteine (F1534C) single nucleotide polymorphism SNP was fixed or nearly fixed in all strains regardless of RR. We observed much more variation in the 1016 valine to isoleucine (V1016I) allele and observed that increasing frequency of the homozygous V1016I allele correlates strongly with increased RR (Pearson corr= 0.905). In agreement with previous studies, we observed a very low frequency of three kdr genotypes, IIFF, VIFF, and IIFC. In this study, we provide a statewide examination of pyrethroid resistance, and demonstrate that permethrin resistance and the genetic markers for resistance are widely present in FL Ae. aegypti. Resistance testing should be included in an effective management program.Author SummaryAedes aegypti and Aedes albopictus can vector a variety of arboviruses that cause diseases and are thus a public health concern. Pyrethroid insecticide resistance is common in Aedes aegypti in many locations worldwide and can adversely affect vector control operations. However, the resistance status of these vectors in Florida is largely unreported and recent local transmission of dengue and Zika viruses has made this information critical for effective control operations. In this study, we showed that permethrin resistance and two common SNPs of the voltage gated sodium channel (V1016I and F1534C) previously associated with pyrethroid resistance were widely present in Florida Aedes aegypti strains. We also observed a strong correlation between the IICC genotype and RR as determined by topical application, which suggests, as have others, that kdr frequency may be a useful indicator of resistance in Aedes aegypti.

scholarly journals CRISPR/Cas9 modified An. gambiae carrying kdr mutation L1014F functionally validate its contribution in insecticide resistance and interaction with metabolic enzymes

2021 ◽  
Author(s):  
Linda Grigoraki ◽  
Ruth Cowlishaw ◽  
Tony Nolan ◽  
Martin Donnelly ◽  
Gareth Lycett ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Glutathione Transferase ◽  
Pyrethroid Resistance ◽  
Target Site ◽  
Mitigation Strategies ◽  
Detoxification Enzymes ◽  
Adult Longevity ◽  
Kdr Mutation ◽  
Over Expression ◽  
A Genome

AbstractInsecticide resistance in Anopheles mosquitoes is a major obstacle in maintaining the momentum in reducing the malaria burden; mitigating strategies require improved understanding of the underlying mechanisms. Mutations in the target site of insecticides (the voltage gated sodium channel for the most widely used pyrethroid class) and over-expression of detoxification enzymes are commonly reported, but their relative contribution to phenotypic resistance remain poorly understood. Here we present a genome editing pipeline to introduce single nucleotide polymorphisms in An. gambiae which we have used to study the effect of the classical kdr mutation L1014F (L995F based on An. gambiae numbering), one of the most widely distributed resistance alleles. Introduction of 1014F in an otherwise fully susceptible genetic background increased levels of resistance to all tested pyrethroids and DDT ranging from 9.9-fold for permethrin to >24-fold for DDT. The introduction of the 1014F allele was sufficient to reduce mortality of mosquitoes after exposure to deltamethrin treated bednets, even as the only resistance mechanism present. When 1014F was combined with over-expression of glutathione transferase Gste2, resistance to permethrin increased further demonstrating the critical combined effect between target site resistance and detoxification enzymes in vivo. We also show that mosquitoes carrying the 1014F allele in homozygosity showed fitness disadvantages including increased mortality at the larval stage and a reduction in fecundity and adult longevity, which can have consequences for the strength of selection that will apply to this allele in the field.Author SummaryEscalation of pyrethroid resistance in Anopheles mosquitoes threatens to reduce the effectiveness of our most important tools in malaria control. Studying the mechanisms underlying insecticide resistance is critical to design mitigation strategies. Here, using genome modified mosquitoes, we functionally characterize the most prevalent mutation in resistant mosquitoes, showing that it confers substantial levels of resistance to all tested pyrethroids and undermines the performance of pyrethroid-treated nets. Furthermore, we show that combining this mutation with elevated levels of a detoxification enzyme further increases resistance. The pipeline we have developed provides a robust approach to quantifying the contribution of different combinations of resistance mechanisms to the overall phenotype, providing the missing link between resistance monitoring and predictions of resistance impact.

scholarly journals Ovitrap Surveillance of Aedes aegypti and Aedes albopictus in Dengue Endemic Areas in Keramat and Shah Alam, Selangor in 2016

2020 ◽  
Vol 17 (3) ◽  
Author(s):  
Noor Afizah A ◽  
Mohd Arif AK ◽  
Nazni WA ◽  
Lee HL
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Species Level ◽  
Dengue Vector ◽  
Entomological Surveillance ◽  
Minimum Number ◽  
Endemic Areas ◽  
The Difference ◽  
Study Sites ◽  
Indoor And Outdoor

Introduction: Entomological surveillance is crucial to determine the abundance of dengue vector and to evaluate breeding areas of Aedes aegypti and Aedes albopictus. The objective of this study is to determine the distribution and breeding preference for both Ae. aegypti and Ae. albopictus in dengue endemic areas. Materials and Methods: Ovitraps surveillance was conducted in two dengue endemic areas; AU2, Keramat and Seksyen 7, Shah Alam, Selangor. A minimum number of 100 ovitraps were deployed for 5 days in the study sites. Samples collected were brought back to the lab and all larvae recovered were identified to species level. Results: The ovitap index (OI) in both localities exceeded the transmission threshold of 10% with the OI recorded ranged from 42.3-79.8% in AU2, Keramat and 16.7-42.9% in Seksyen 7, Shah Alam. Ae. albopictus was the dominant species in AU2 Keramat with the highest ratio Ae. aegypti to Ae. albopictus recorded was 1.00:22.79. Nonetheless, in Seksyen 7, Shah Alam the difference in Ae. aegypti to Ae. albopictus ratio is not really prominent with 1.00:3.61 for ovitraps deployed outdoor and 3.40:1.00 for ovitraps set indoor. It was determined that single infestation of either Ae. aegypti or Ae. albopictus is more frequent for ovitraps deployed indoor and/or outdoor, respectively. It was also determined that mixed infestations were found in this study indicating that both species can oviposit in the same container. Conclusion: This study indicates that OI is still above transmission threshold in both study sites. While Ae. aegypti and Ae. albopictus remain as a dominant indoor and outdoor breeder, respectively, mixed breeding of Aedes species in a same container was also observed.

Efektivitas Ekstrak Umbi Gadung (Dioscorea Hispida Dents) Dalam Pengendalian Larva Aedes Aegypti Dan Aedes Albopictus

2018 ◽  
Vol 3 (3) ◽  
pp. 515
Author(s):  
Ratna Sari Dewi
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Experimental Research ◽  
Hemorrhagic Fever ◽  
Control Group ◽  
Anova Analysis ◽  
Natural Insecticides ◽  
The Difference ◽  
Short Time ◽  
Tuber Extract

<p><em>Dengue Hemorrhagic Fever is one of the diseases that disease quickly and can cause death in a short time. One of the natural insecticides in killing Aedes aegypti larvae and Aedes alboipictus is by using tuber bulbs extract</em><em>.</em><em>The purpose of this research is to know the difference of various concentrations of tuber bulbs extract on the death of Aedes aegypti larva and Aedes alboipictus. This design of research is experimental research </em><em>and Anova analysis</em><em>. The number of population in this study as many as 780 larvae. The concentration used in this research is 0.02%, 0.05%, 0.10%, 0.15%, 0.20%. The results showed that the average deaths of the two different test larvae for the lowest concentrations of 0.02% the average death of the test larvae were 5.80 deaths in the Aedes aegypti larvae and 4.80 deaths in the Aedes albopictus larvae.</em><em> </em><em>The conclusion of this research is the difference of concentration 0,02%, 0,05%, 0,10%, 15%, and 0,20% Gadung Umbi extract to Aedes aegypti and Aedes albopictus larvae mortality and concentration correlation 0,02 %, 0.05%, 0.10%, 0.15%, and 0.20% of Gadung Tuber extract on the death of Aedes aegypti and Aedes albopictus larvae.</em><em></em></p><p> </p><p>Demam Berdarah  <em>Dengue </em> merupakan salah satu penyakit yang perjalanan penyakitnya cepat dan dapat menyebabkan kematian dalam waktu singkat. Salah satu insektisida alami dalam membunuh larva <em>Aedes</em><em> </em><em>aegypti</em><em> </em>dan <em>Aedes</em><em> </em><em>alboipictus</em> adalah dengan menggunakan ekstrak umbi gadung. Tujuan penelitian ini untuk mengetahui perbedaan berbagai konsentrasi ekstrak umbi gadung terhadap kematian larva <em>Aedes</em><em> </em><em>aegypti</em><em> </em>dan <em>Aedes</em><em> </em><em>alboipictus</em><em>.</em> Jenis penelitian ini merupakan penelitian ekperimen dengan menggunakan rancangan penelitian <em>Posttest Only Control Group.</em><em> </em>Jumlah populasi dalam penelitian ini sebanyak 780 ekor larva. Konsentrasi yang digunakan pada penelitian ini yaitu 0,02%, 0,05%, 0,10%, 0,15%, 0,20%. Penelitian ini menggungakan analisis Anova satu arah. Hasil penelitian menunjukkan bahwa rata-rata kematian kedua larva uji yang berbeda untuk konsentrasi terendah 0,02% rata-rata kematian  larva uji sebesar 5,80 kematian pada larva nyamuk <em>Aedes aegypti</em> dan 4,80 kematian pada larva nyamuk <em>Aedes albopictus</em>. Kesimpulan dari hasil penelitian ini adalah adanya perbedaan konsentrasi 0,02%, 0,05%, 0,10%, 15%, dan 0,20% ekstrak Umbi Gadung<em> </em>terhadap kematian larva <em>Aedes aegypti </em>dan <em>Aedes albopictus</em><em> </em>serta adanya hubungan konsentrasi 0,02%, 0,05%, 0,10%, 0,15%, dan 0,20% ekstrak Umbi Gadung terhadap kematian larva <em>Aedes aegypti </em>dan <em>Aedes albopictus</em>.</p>

scholarly journals Insecticide resistance status of Aedes aegypti in Bangladesh

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Hasan Mohammad Al-Amin ◽  
Fatema Tuj Johora ◽  
Seth R. Irish ◽  
Muhammad Riadul Haque Hossainey ◽  
Lucrecia Vizcaino ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Pyrethroid Resistance ◽  
Control Strategies ◽  
Resistance Mechanisms ◽  
Capital City ◽  
Detoxification Enzymes ◽  
Knockdown Resistance ◽  
Metabolic Resistance ◽  
Pyrethroid Insecticides

Abstract Background Arboviral diseases, including dengue and chikungunya, are major public health concerns in Bangladesh where there have been unprecedented levels of transmission reported in recent years. The primary approach to control these diseases is to control the vector Aedes aegypti using pyrethroid insecticides. Although chemical control has long been practiced, no comprehensive analysis of Ae. aegypti susceptibility to insecticides has been conducted to date. The aim of this study was to determine the insecticide resistance status of Ae. aegypti in Bangladesh and investigate the role of detoxification enzymes and altered target site sensitivity as resistance mechanisms. Methods Eggs of Aedes mosquitoes were collected using ovitraps from five districts across Bangladesh and in eight neighborhoods of the capital city Dhaka, from August to November 2017. CDC bottle bioassays were conducted for permethrin, deltamethrin, malathion, and bendiocarb using 3- to 5-day-old F0–F2 non-blood-fed female mosquitoes. Biochemical assays were conducted to detect metabolic resistance mechanisms, and real-time PCR was performed to determine the frequencies of the knockdown resistance (kdr) mutations Gly1016, Cys1534, and Leu410. Results High levels of resistance to permethrin were detected in all Ae. aegypti populations, with mortality ranging from 0 to 14.8% at the diagnostic dose. Substantial resistance continued to be detected against higher (2×) doses of permethrin (5.1–44.4% mortality). Susceptibility to deltamethrin and malathion varied between populations while complete susceptibility to bendiocarb was observed in all populations. Significantly higher levels of esterase and oxidase activity were detected in most of the test populations as compared to the susceptible reference Rockefeller strain. A significant association was detected between permethrin resistance and the presence of Gly1016 and Cys1534 homozygotes. The frequency of kdr (knockdown resistance) alleles varied across the Dhaka Aedes populations. Leu410 was not detected in any of the tested populations. Conclusions The detection of widespread pyrethroid resistance and multiple resistance mechanisms highlights the urgency for implementing alternate Ae. aegypti control strategies. In addition, implementing routine monitoring of insecticide resistance in Ae. aegypti in Bangladesh will lead to a greater understanding of susceptibility trends over space and time, thereby enabling the development of improved control strategies.

scholarly journals Insecticide resistance status and mechanisms in Aedes aegypti populations from Senegal

2021 ◽  
Vol 15 (5) ◽  
pp. e0009393
Author(s):  
Ndeye Marie Sene ◽  
Konstantinos Mavridis ◽  
El Hadji Ndiaye ◽  
Cheikh Tidiane Diagne ◽  
Alioune Gaye ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Pyrethroid Resistance ◽  
Control Strategies ◽  
Resistance Mechanisms ◽  
Northern Region ◽  
Target Site ◽  
Limited Information ◽  
Resistance Mutations

Aedes aegypti is the main epidemic vector of arboviruses in Africa. In Senegal, control activities are mainly limited to mitigation of epidemics, with limited information available for Ae. aegypti populations. A better understanding of the current Ae. aegypti susceptibility status to various insecticides and relevant resistance mechanisms involved is needed for the implementation of effective vector control strategies. The present study focuses on the detection of insecticide resistance and reveals the related mechanisms in Ae. aegypti populations from Senegal. Bioassays were performed on Ae. aegypti adults from nine Senegalese localities (Matam, Louga, Barkedji, Ziguinchor, Mbour, Fatick, Dakar, Kédougou and Touba). Mosquitoes were exposed to four classes of insecticides using the standard WHO protocols. Resistance mechanisms were investigated by genotyping for pyrethroid target site resistance mutations (V1016G, V1016I, F1534C and S989P) and measuring gene expression levels of key detoxification genes (CYP6BB2, CYP9J26, CYP9J28, CYP9J32, CYP9M6, CCEae3a and GSTD4). All collected populations were resistant to DDT and carbamates except for the ones in Matam (Northern region). Resistance to permethrin was uniformly detected in mosquitoes from all areas. Except for Barkédji and Touba, all populations were characterized by a susceptibility to 0.75% Permethrin. Susceptibility to type II pyrethroids was detected only in the Southern regions (Kédougou and Ziguinchor). All mosquito populations were susceptible to 5% Malathion, but only Kédougou and Matam mosquitoes were susceptible to 0.8% Malathion. All populations were resistant to 0.05% Pirimiphos-methyl, whereas those from Louga, Mbour and Barkédji, also exhibited resistance to 1% Fenitrothion. None of the known target site pyrethroid resistance mutations was present in the mosquito samples included in the genotyping analysis (performed in > 1500 samples). In contrast, a remarkably high (20-70-fold) overexpression of major detoxification genes wasobserved, suggesting that insecticide resistance is mostly mediated through metabolic mechanisms. These data provide important evidence to support dengue vector control in Senegal.

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