scholarly journals The discovery of a novel knockdown resistance (kdr) mutation A1007G on Aedes aegypti (Diptera: Culicidae) from Malaysia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wan Fatma Zuharah ◽  
Maryam Sufian

AbstractThe usage of insecticide rendered the successful vector control program with the high usage of the pyrethroid. However, the intensive and extensive use of pyrethroid, causing resistance in Aedesaegypti and hampered the control program. Knockdown resistance (kdr) resulting from the Voltage-Gated Sodium Channel (VGSC) is one of the mechanisms of resistance in pyrethroid group insecticide. Investigating the phenotypic status of Ae.aegypti mosquitoes is a lead in knowing the current resistance status and as an indicator of the genotypic resistance. In this study, we investigate the resistance in phenotypic and genotypic of Ae.aegypti with a new kdr mutation point A1007G was detected. Using the adult bioassay, we tested the phenotypic resistance from the Selangor state against 0.75% permethrin, 0.05% deltamethrin with and without the addition of PBO synergist. Permethrin-resistant and deltamethrin-resistant, including susceptible samples, were subjected to genotyping analysis on mutation point in domain II and domain III of Voltage-Gated Sodium Channel (VGSC). Adult bioassay revealed that the Ae.aegypti was highly resistance toward 0.75% permethrin and 0.05% deltamethrin. The bioassay with the presence of PBO synergist showed an increment of mortality rate, but Ae.aegypti status is still resistance towards both insecticides. Genotyping result showed that three common kdr mutations (S989P, V1016G, and F1534C) have existed in the Ae.aegypti population. A new novel mutation on A1007G was also detected in this population, which is the first time reported. This study has brought a piece of information on the current resistance status in Ae.aegypti in Malaysia. The detection of new mutation point of A1007G has added the knowledge on the resistance in mosquitoes. Thus, this study will aid with the decision making in the usage of insecticides in the vector control program; before this invaluable insecticide rendered ineffective in killing mosquitoes.

2020 ◽  
Author(s):  
Wan Fatma Zuharah ◽  
Maryam Sufian

Abstract Background: The usage of insecticide rendered the successful vector control program with the high usage of the pyrethroid. However, the intensive and extensive use of pyrethroid, causing resistance in Aedes aegypti and hampered the control program. Knockdown resistance (kdr) resulting from the Voltage-Gated Sodium Channel (vgsc) is one of the mechanisms of resistance in pyrethroid group insecticide. Investigating the phenotypic status of Ae. aegypti mosquitoes is a lead in knowing the current resistance status and as an indicator of the genotypic resistance. In this study, we investigate the resistance in phenotypic and genotypic of Ae. aegypti with a new kdr mutation point, A1007G was detected. Methods: Using the adult bioassay, we tested the phenotypic resistance from the Selangor state against 0.75% permethrin, 0.05% deltamethrin with and without the addition of PBO synergist. Permethrin-resistant and deltamethrin-resistant, including susceptible samples, were subjected to genotyping analysis on mutation point in domain II and domain III of Voltage-Gated Sodium Channel (vgsc). Results: Adult bioassay revealed that the Ae. aegypti was highly resistance toward 0.75% permethrin and 0.05% deltamethrin. The bioassay with the presence of PBO synergist showed an increment of mortality rate, but the status of Ae. aegypti is still resistance towards both insecticides. Genotyping result showed that three common kdr mutations (S989P, V1016G, and F1534C) have existed in the Ae. aegypti population. Luckily, a new mutation on A1007G was also detected in this population, and this is the first time reported. Conclusions: This study has brought a piece of information on the current resistance status in Ae. aegypti in Malaysia. The detection of new mutation point of A1007G has added the knowledge on the resistance in mosquitoes. Thus, this study will aid the decision in using the insecticide usage in vector control program before this invaluable insecticide rendered ineffective in killing mosquitoes.


2019 ◽  
Author(s):  
Raja Babu S. Kushwah ◽  
Taranjeet Kaur ◽  
Cherry L. Dykes ◽  
Ravi H. Kumar ◽  
Neera Kapoor ◽  
...  

AbstractBackgroundAedes 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 were 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 collected between October 2014 and April 2015 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 and development of PCR-based diagnostics have implications for insecticide resistance management. Monitoring of F1534L-kdr in other populations and studies on their functional role in altering neuro-sensitivity is warranted.


2021 ◽  
Author(s):  
Mas Azlin M. Akhir ◽  
Mustafa F. F. Wajidi ◽  
Sébastien Lavoué ◽  
Ghows Azzam ◽  
Izhan Shahrin Jaafar ◽  
...  

Abstract Background: Characterization of the insecticide resistance mechanism imparts the society with the information on the evolutionary process involved in the adaptation of Aedes aegypti mosquito to environmental changes. Investigating the phenotypic status of the target mosquitoes, their resistance level as well as elucidating the genotypic profile provides information about the involvement of insecticide resistance mechanism, in terms of portraying the evolution of resistance in the field, to eventually managing vector control programmes. In this current study, we investigated the quantification responses for the phenotypic and genotypic resistance of Ae. aegypti population from different states in Malaysia. Methods: We tested insecticide susceptibility status of adult Ae. aegypti from populations of States of Penang, Selangor and Kelantan (Peninsular Malaysia) against 0.25% permethrin and 0.25% pirimiphos-methyl through WHO bioassay kit. Permethrin-resistant and permethrin susceptible samples were then genotyped for domains II and III in the voltage gated sodium channel (vgsc) gene using allele specific PCR (AS-PCR) for the presence of diagnostic single nucleotide mutations. AS-PCR results were then validated in sequencing these two domains to identify any possible additional point mutations. Results: Adult WHO bioassay 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 (i.e. S989P, V1016G and F1534C) were associated with pyrethroid resistance in these populations. We also report for the first time the presence of the A1007G mutation in Malaysian populations of Ae. aegypti.Conclusions: This study brings an insight on the occurrence and association of point mutations with insecticide resistance in Malaysian populations of Ae. aegypti. The results reveal the widespread of several kdr mutations in the field with the consequence to compromise the use of pyrethroid insecticides in vector control programmes. Knowledge on the distribution of target site resistance throughout Malaysia is vital to ensure the success of the insecticide-based vector control programme.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Raja Babu S. Kushwah ◽  
Taranjeet Kaur ◽  
Cherry L. Dykes ◽  
H. Ravi Kumar ◽  
Neera Kapoor ◽  
...  

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