Dataset Information

Knockdown resistance (kdr) gene of Aedes aegypti in Malaysia with the discovery of a novel regional specific point mutation A1007G.

ABSTRACT:

Background

Improved understanding of the molecular basis of insecticide resistance may yield new opportunities for control of relevant disease vectors. In this current study, we investigated the quantification responses for the phenotypic and genotypic resistance of Aedes aegypti populations from different states in Malaysia.

Methods

We tested the insecticide susceptibility status of adult Ae. aegypti from populations of three states, Penang, Selangor and Kelantan (Peninsular Malaysia), against 0.25% permethrin and 0.25% pirimiphos-methyl using the World Health Organisation (WHO) adult bioassay method. Permethrin-resistant and -susceptible samples were then genotyped for domains II and III in the voltage-gated sodium channel (vgsc) gene using allele-specific polymerase chain reaction (AS-PCR) for the presence of any diagnostic single-nucleotide mutations. To validate AS-PCR results and to identify any possible additional point mutations, these two domains were sequenced.

Results

The bioassays revealed that populations of Ae. aegypti from these three states were highly resistant towards 0.25% permethrin and 0.25% pirimiphos-methyl. Genotyping results showed that three knockdown (kdr) mutations (S989P, V1016G and F1534C) were associated with pyrethroid resistance within these populations. The presence of a novel mutation, the A1007G mutation, was also detected.

Conclusions

This study revealed the high resistance level of Malaysian populations of Ae. aegypti to currently used insecticides. The resistance could be due to the widespread presence of four kdr mutations in the field and this could potentially impact the vector control programmes in Malaysia and alternative solutions should be sought.

SUBMITTER: Akhir MAM

PROVIDER: S-EPMC8988349 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature

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Publications

Knockdown resistance (kdr) gene of Aedes aegypti in Malaysia with the discovery of a novel regional specific point mutation A1007G.

Akhir Mas Azlin M MAM Wajidi Mustafa F F MFF Lavoué Sébastien S Azzam Ghows G Jaafar Izhan Shahrin IS Awang Besar Noor Aslinda Ummi NAU Ishak Intan H IH

Parasites & vectors 20220406 1

<h4>Background</h4>Improved understanding of the molecular basis of insecticide resistance may yield new opportunities for control of relevant disease vectors. In this current study, we investigated the quantification responses for the phenotypic and genotypic resistance of Aedes aegypti populations from different states in Malaysia.<h4>Methods</h4>We tested the insecticide susceptibility status of adult Ae. aegypti from populations of three states, Penang, Selangor and Kelantan (Peninsular Mala ...[more]

PMID: 35387654

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Project description:BackgroundControl of Aedes aegypti, the mosquito vector of dengue, chikungunya and yellow fever, is a challenging task. Pyrethroid insecticides have emerged as a preferred choice for vector control but are threatened by the emergence of resistance. The present study reports a focus of pyrethroid resistance and presence of two kdr mutations--F1534C and a novel mutation T1520I, in Ae. aegypti from Delhi, India.Methodology/principal findingsInsecticide susceptibility status of adult-female Ae. aegypti against DDT (4%), deltamethrin (0.05%) and permethrin (0.75%) was determined using WHO's standard insecticide susceptibility kit, which revealed resistance to DDT, deltamethrin and permethrin with corrected mortalities of 35%, 72% and 76% respectively. Mosquitoes were screened for the presence of kdr mutations including those reported earlier (I1011V/M, V1016G/I, F1534C, D1794Y and S989P), which revealed the presence of F1534C and a novel mutation T1520I. Highly specific PCR-RFLP assays were developed for genotyping of these two mutations. Genotyping using allele specific PCR and new PCR-RFLP assays revealed a high frequency of F1534C (0.41-0.79) and low frequency of novel mutation T1520I (0.13). The latter was observed to be tightly linked with F1534C and possibly serve as a compensatory mutation. A positive association of F1534C mutation with DDT and deltamethrin resistance in Ae. aegypti was established. However, F1534C-kdr did not show significant protection against permethrin.Conclusions/significanceThe Aedes aegypti population of Delhi is resistant to DDT, deltamethrin and permethrin. Two kdr mutations, F1534C and a novel mutation T1520I, were identified in this population. This is the first report of kdr mutations being present in the Indian Ae. aegypti population. Highly specific PCR-RFLP assays were developed for discrimination of alleles at both kdr loci. A positive association of F1534C mutation with DDT and deltamethrin resistance was confirmed.

Project description:BackgroundAedes aegypti is a primary vector of dengue, chikungunya and Zika infections in India. In the absence of specific drugs or safe and effective vaccines for these infections, their control relies mainly on vector control measures. The emergence of insecticide resistance in vectors, especially against pyrethroids, is a serious threat to the insecticide-based vector control programme. This study reports the presence of multiple knockdown resistance (kdr) mutations present in an Ae. aegypti population from Bengaluru (India), including a new mutation F1534L.MethodsAedes aegypti collected from Bengaluru were subjected to insecticide susceptibility tests with DDT, deltamethrin and permethrin. The DNA sequencing of partial domain II, III and IV of the voltage-gated sodium channel (VGSC) was performed to screen kdr mutations present in the population and PCR-based assays were developed for their detection. Genotyping of kdr mutations was done using PCR-based assays, allelic frequencies were determined, and tests of genetic association of kdr mutations with the insecticide resistance phenotype were performed.ResultsThe Ae. aegypti population was resistant to DDT, deltamethrin and permethrin. The DNA sequencing of the VGSC revealed the presence of four kdr mutations, i.e. S989P and V1016G in domain II and two alternative kdr mutations F1534C and F1534L in domain III. Allele-specific PCR assays (ASPCR) were developed for the detection of kdr mutations S989P and V1016G and an existing PCR-RFLP based strategy was modified for the genotyping of all three known kdr mutations in domain III (F1534L, F1534C and T1520I). Genotyping of Ae. aegypti samples revealed a moderate frequency of S989P/V1016G (18.27%) and F1534L (17.48%), a relatively high frequency of F1534C (50.61%) and absence of T1520I in the population. Mutations S989P and V1016G were in complete linkage disequilibrium in this population while they were in linkage equilibrium with kdr mutations F1534C and F1534L. The alleles F1534C and F1534L are genetically associated with permethrin resistance.ConclusionsA new kdr mutation, F1534L, was found in an Ae. aegypti population from Bengaluru (India), co-occurring with the other three mutations S989P, V1016G and F1534C. The findings of a new mutation have implications for insecticide resistance management.

Project description:BackgroundAedes borne viral diseases, notably dengue, are increasingly reported in Cameroon with Aedes aegypti being a major vector. Data on insecticide resistance of this vector and underlying mechanisms needed for outbreak preparedness remain scarce in Cameroon. Here, we present the nationwide distribution of insecticide resistance in Ae. aegypti and investigate the potential resistance mechanisms involved.MethodsImmature stages of Ae. aegypti were collected between March and July 2017 in 13 locations across Cameroon and reared until G1/G2/G3 generation. Larval, adult bioassays, and piperonyl butoxide (PBO) synergist assays were carried out according to World Health Organization guidelines. F1534C mutation was genotyped using allele specific polymerase chain reaction in field collected adults (Go) and the polymorphism of the sodium channel gene was assessed. The χ2 test was used to compare the mortality rate between bioassays with insecticides only and bioassays after preexposure to PBO synergist.ResultsLarval bioassay revealed that all the three populations tested with temephos were susceptible. Adult bioassays showed a good level of susceptibility toward both pyrethroids tested, 0.25% permethrin and 0.05% deltamethrin, with six out of 10 populations susceptible. However, two populations (Douala and Edéa) were resistant (deltamethrin [73.2-92.5% mortality], permethrin [2.6-76.3% mortality]). The resistance to 4% dichlorodiphenyltrichloroethane was observed in four out of 10 populations tested (16.8-87.1% mortality). Resistance was also reported to carbamates including 0.1% propoxur (60.8-87.1% mortality) and to 0.1% bendiocarb (82.9% mortality). All populations tested were fully susceptible to 1% fenitrothion. A partial recovery of susceptibility was observed in the pyrethroid resistant population of Douala after pre-exposed to PBO suggesting the implication of cytochrome P450 monoxygenases permethrin resistance. Genotyping and sequencing detected the F1534C kdr mutation in the two pyrethroid resistant locations of Edéa and Douala, with allelic frequency of 3.3% and 33.3% respectively. However, the high genetic diversity of the sodium channel gene supports the recent introduction of this mutation in Cameroon.ConclusionsThis study revealed the contrasting resistance profiles to insecticides of Ae. aegypti populations in Cameroon suggesting that, instead of a unique nationwide control approach, a regionally adapted strategy will be needed to control this vector. The localised distribution of the F1534C kdr mutation supports this region-specific control strategy.

Project description:Aedes aegypti is the primary vector of dengue, chikungunya, Zika, and urban yellow fever. Insecticides are often the most effective tools to rapidly decrease the density of vector populations, especially during arbovirus disease outbreaks. However, the intense use of insecticides, particularly pyrethroids, has selected for resistant mosquito populations worldwide. Mutations in the voltage gated sodium channel (NaV) are among the principal mechanisms of resistance to pyrethroids and DDT, also known as "knockdown resistance," kdr. Here we report studies on the origin and dispersion of kdr haplotypes in samples of Ae. aegypti from its worldwide distribution. We amplified the IIS6 and IIIS6 NaV segments from pools of Ae. aegypti populations from 15 countries, in South and North America, Africa, Asia, Pacific, and Australia. The amplicons were barcoded and sequenced using NGS Ion Torrent. Output data were filtered and analyzed using the bioinformatic pipeline Seekdeep to determine frequencies of the IIS6 and IIIS6 haplotypes per population. Phylogenetic relationships among the haplotypes were used to infer whether the kdr mutations have a single or multiple origin. We found 26 and 18 haplotypes, respectively for the IIS6 and IIIS6 segments, among which were the known kdr mutations 989P, 1011M, 1016I and 1016G (IIS6), 1520I, and 1534C (IIIS6). The highest diversity of haplotypes was found in African samples. Kdr mutations 1011M and 1016I were found only in American and African populations, 989P + 1016G and 1520I + 1534C in Asia, while 1534C was present in samples from all continents, except Australia. Based primarily on the intron sequence, IIS6 haplotypes were subdivided into two well-defined clades (A and B). Subsequent phasing of the IIS6 + IIIS6 haplotypes indicates two distinct origins for the 1534C kdr mutation. These results provide evidence of kdr mutations arising de novo at specific locations within the Ae. aegypti geographic distribution. In addition, our results suggest that the 1534C kdr mutation had at least two independent origins. We can thus conclude that insecticide selection pressure with DDT and more recently with pyrethroids is selecting for independent convergent mutations in NaV.

Project description:BackgroundAedes aegypti and Aedes albopictus are important vectors of human arboviruses, transmitting arboviral diseases such as yellow fever, dengue, chikungunya and Zika. These two mosquitoes coexist on Hainan Island and the Leizhou Peninsula in China. Over the past 40 years, the distribution of Ae. albopictus has gradually expanded in these areas, while the distribution of Ae. aegypti has declined dramatically mainly due to the ecological changes and some other factors such as heavy use of insecticide indoor based on endophagic bloodfeeding of the species.MethodsThis study focused on the knockdown resistance (kdr) genes of both mosquitoes, investigated their mutations, and analyzed their haplotype and evolutionary diversity combined with population genetic features based on the ND4/ND5 genes to further elucidate the molecular mechanisms underlying the development of insecticide resistance in both mosquitoes.ResultsThree mutations, S989P, V1016G and F1534C, were found to be present in Ae. aegypti populations, and the three mutations occurred synergistically. Multiple mutation types (F1534C/S/L/W) of the F1534 locus are found in Ae. albopictus populations, with the three common mutations F1534C, F1534S and F1534L all having multiple independent origins. The F1534W (TTC/TGG) mutation is thought to have evolved from the F1534L (TTC/TTG) mutation. The F1534S (TTC/TCG) mutation has evolved from the F1534S (TTC/TCC) mutation. The most common form of mutation at the F1534 locus found in this study was S1534C, accounting for 20.97%, which may have evolved from the F1534C mutation. In addition, a new non-synonymous mutation M1524I and 28 synonymous mutations were identified in Ae. albopictus populations. Correlation analysis showed that the genetic diversity of Ae. aegypti and Ae. albopictus populations did not correlate with their kdr haplotype diversity (P>0.05), but strong gene flow between populations may have contributed to the evolution of the kdr gene.ConclusionThe study of kdr gene evolution in the two mosquito species may help to identify the evolutionary trend of insecticide resistance at an early stage and provide a theoretical basis for improving the efficiency of biological vector control and subsequent research into new insecticides.

Project description:BackgroundThe Aedes aegypti mosquito is the primary vector for dengue, chikungunya, yellow fever and Zika viruses worldwide. The first record of Ae. aegypti in southwestern Saudi Arabia was in 1956. However, the first outbreak and cases of dengue fever were reported in 1994, and cases have increased in recent years. Vector control for Ae. aegypti mainly uses pyrethroid insecticides in outdoor and indoor space spraying. The constant use of pyrethroids has exerted intense selection pressure for developing target-site mutations in the voltage-gated sodium channel (vgsc) gene in Ae. Aegypti against pyrethroids-mutations that have led to knockdown resistance (kdr).MethodsAedes aegypti field populations from five regions (Jazan, Sahil, Makkah, Jeddah and Madinah) of southwestern Saudi Arabia were genotyped for known kdr mutations in domains IIS6 and IIIS6 of the vgsc gene using polymerase chain reaction (PCR) amplification and sequencing. We estimated the frequency of kdr mutations and genotypes from Saudi Arabia as well as from other countries, Thailand, Myanmar (Southeast Asia) and Uganda (East Africa). We constructed haplotype networks to infer the evolutionary relationships of these gene regions.ResultsThe three known kdr mutations, S989P, V1016G (IIS6) and F1534C (IIIS6), were detected in all five regions of Saudi Arabia. Interestingly, the triple homozygous wild genotype was reported for the first time in two individuals from the highlands of the Jazan region and one from the Al-Quoz, Sahil region. Overall, nine genotypes comprising four haplotypes were observed in southwestern Saudi Arabia. The median-joining haplotype networks of eight populations from Saudi Arabia, Southeast Asia and East Africa for both the IIS6 and IIIS6 domains revealed that haplotype diversity was highest in Uganda and in the Jazan and Sahil regions of Saudi Arabia, whereas haplotype diversity was low in the Jeddah, Makkah and Madinah regions. Median-joining haplotype networks of both domains indicated selection acting on the kdr-mutation containing haplotypes in Saudi Arabia.ConclusionsThe presence of wild type haplotypes without any of the three kdr mutations, i.e. that are fully susceptible, in Saudi Arabia indicates that further consideration should be given to insecticide resistance management strategies that could restore pyrethroid sensitivity to the populations of Ae. aegypti in Saudi Arabia as part of an integrative vector control strategy.

Dataset Information

Knockdown resistance (kdr) gene of Aedes aegypti in Malaysia with the discovery of a novel regional specific point mutation A1007G.

Background

Methods

Results

Conclusions

Publications

Knockdown resistance (kdr) gene of Aedes aegypti in Malaysia with the discovery of a novel regional specific point mutation A1007G.

Similar Datasets

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