Evaluation of resistance to pyrethroid and organophosphate adulticides, and kdr genotyping in Ades aegypti populations from Roraima, the Northernmost Brazilian State

Abstract Background Roraima is the northernmost State in Brazil and makes international borders with Venezuela and Guyana. Although mostly covered by the tropical forests, the urban centers are highly infested with Ae. aegypti and endemic for dengue, Zika and chikungunya. Here we presented the levels of Ae. aegypti infestation and number of arboviruses cases between 2015 and 2018 in the studied localities. We evaluated the insecticide resistance status of Ae. aegypti populations from the capital Boa Vista, two cities in international borders: Pacaraima and Bonfim, and Rorainópolis in the limit with Amazonas State, collected in 2016 and 2018. Methods WHO like tube tests with the pyrethroid deltamethrin (0.05 and 0.12%) and the organophosphate malathion (0.7%) were conducted. Genotyping of kdr mutations, related to resistance to pyrethroids, were performed for the SNP variations in the sites 1016 and 1534 of the voltage gated sodium channel gene (Na V ) with a TaqMan qPCR approach. Results Only Ae. aegypti was present in our collection, meaning that there is still a barrier that Ae. albopictus was still not able to transpose from Amazonas toward Roraima. All Ae. aegypti populations were susceptible to 0.7% malathion in 2016, however mortality dropped to under 90% in Bonfim and Pacaraima in 2018. All populations were resistant to 0.5% deltamethrin in both years. The time that 50% of females suffered knockdown ( Kd T 50 ) under exposition to 0.5% deltamethrin was 3.3-5.9 fold longer in mosquitoes from the populations compared to Rockefeller. Only Pacaraima (2018) remained resistant to 0.12% deltamethrin. The kdr genotyping revealed the absence of the wild-type Na V S haplotype (1016Val + 1534Phe) in populations from Roraima, meaning that all tested individuals had a genetic background for resistance to pyrethroid. The double kdr Na V R2 haplotype (1016Ile + 15434Cys) was under higher frequencies in all populations except Rorainópolis, where this haplotype seems to have arrived recently. Conclusions These results are important to the knowledge about insecticide resistance status of Ae. aegypti populations from Roraima and will help to improve vector control strategies that may be applied to diverse localities with similar conditions.

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Evaluation of resistance to pyrethroid and organophosphate adulticides and kdr genotyping in Aedes aegypti populations from Roraima, the Northernmost Brazilian State

10.21203/rs.2.21242/v2 ◽

2020 ◽

Author(s):

Ramão Luciano Nogueira Hayd ◽

Luana Carrara ◽

Joel de Melo Lima ◽

Nathalia Coelho Vargas de Almeida ◽

José Bento Pereira Lima ◽

...

Keyword(s):

Insecticide Resistance ◽

Pyrethroid Resistance ◽

Control Strategies ◽

World Health ◽

Urban Centers ◽

International Borders ◽

Two Cities ◽

Health Organization ◽

Amazonas State ◽

Urban Conditions

Abstract Background. Roraima, the northernmost State in Brazil, borders Venezuela and Guyana. Although mostly covered by the tropical forests, the urban centers of this State are highly infested with Ae. aegypti and endemic for dengue, Zika and chikungunya. Herein we present the levels of Ae. aegypti infestation and number of arboviruses cases between 2015 and 2018 in the studied localities. We accessed the insecticide resistance status of Ae. aegypti populations from the capital Boa Vista, two cities on international borders (Pacaraima and Bonfim) and Rorainópolis bordering Amazonas State, in order to evaluate the chemical control efficacy in these localities. Methods. Tests with World Health Organization (WHO)-like tubes impregnated with the pyrethroid deltamethrin (0.05 and 0.12%) and the organophosphate malathion (0.7%) were conducted with Ae. aegypti from Boa Vista, Pacaraima, Bonfim and Rorainópolis, collected in 2016 and 2018. Genotyping of kdr mutations, related to resistance to pyrethroids, was performed for the SNP variations in the sites 1016 and 1534 of the voltage gated sodium channel gene (NaV) with a TaqMan qPCR approach. Results. Ae. albopictus was absent in our collections, and therefore only Ae. aegypti was tested. All Ae. aegypti populations were susceptible to 0.7% malathion in 2016, however mortality dropped to under 90% in Bonfim and Pacaraima populations in 2018. All populations were resistant to 0.05% deltamethrin in both years. The time that 50% of females suffered knockdown (KdT50) under exposition to 0.05% deltamethrin was 3.3-5.9 fold longer in mosquitoes from the populations compared to the susceptible strain Rockefeller. Only Pacaraima population (2018) remained resistant to 0.12% deltamethrin. The kdr genotyping revealed the absence of the wild-type NaVS haplotype (1016Val + 1534Phe) in the populations from Roraima, signifying that all tested insects had a genetic background for pyrethroid resistance. The double kdr NaVR2 haplotype (1016Ile + 15434Cys) was present in higher frequencies in all populations except Rorainópolis, where this haplotype seems to have arrived recently. Conclusions. These results are important for the knowledge about insecticide resistance status of Ae. aegypti populations from Roraima and will help to improve vector control strategies that may be applied to diverse localities under similar geographical and urban conditions.

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Evaluation of resistance to pyrethroid and organophosphate adulticides and kdr genotyping in Aedes aegypti populations from Roraima, the Northernmost Brazilian State

10.21203/rs.2.21242/v3 ◽

2020 ◽

Author(s):

Ramão Luciano Nogueira Hayd ◽

Luana Carrara ◽

Joel de Melo Lima ◽

Nathalia Coelho Vargas de Almeida ◽

José Bento Pereira Lima ◽

...

Keyword(s):

Insecticide Resistance ◽

Pyrethroid Resistance ◽

Control Strategies ◽

World Health ◽

Urban Centers ◽

International Borders ◽

Two Cities ◽

Health Organization ◽

Amazonas State ◽

Urban Conditions

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The potential for insecticide resistance in Glossina (Diptera: Glossinidae)— an investigation by computer simulation and chemical analysis

Bulletin of Entomological Research ◽

10.1017/s0007485300010221 ◽

1981 ◽

Vol 71 (4) ◽

pp. 691-702 ◽

Cited By ~ 12

Author(s):

I. Maudlin ◽

C. H. Green ◽

F. Barlow

Keyword(s):

Insecticide Resistance ◽

Control Strategies ◽

Glossina Morsitans Morsitans ◽

Wild Type ◽

Tsetse Control ◽

Population Extinction ◽

Tsetse Population ◽

Control Programmes ◽

Evolution Of Resistance ◽

Relationship Of

AbstractA computer model of a tsetse population was developed to determine whether insecticide resistance could evolve as a result of current tsetse control programmes. Chemical analyses were also carried out which showed that Glossina morsitans morsitans Westw. can metabolise DDT to DDE, indicating a potential for insecticide resistance in this species. The model showed that a completely isolated tsetse population stands little chance of surviving attacks with insecticides repeated at short intervals. However, when sufficient time is allowed between applications, such a population may survive and evolution of resistance take place. Given a small amount of immigration, the evolution of resistance is retarded, but population extinction is prevented. The degree of resistance developed by a population also depends on the dominance relationship of a resistant gene with its wild-type allele and on the reproductive fitness of the mutant. It is suggested that control strategies are adopted which would minimise the risk of insecticide resistance becoming a problem in tsetse and that susceptibility studies are carried out both before spraying operations and on any residual population post-spraying.

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High insecticide resistance mediated by different mechanisms in Culex quinquefasciatus populations from the city of Yaoundé, Cameroon

Scientific Reports ◽

10.1038/s41598-021-86850-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Abdou Talipouo ◽

Konstantinos Mavridis ◽

Elysée Nchoutpouen ◽

Borel Djiappi-Tchamen ◽

Emmanouil Alexandros Fotakis ◽

...

Keyword(s):

Insecticide Resistance ◽

Vector Control ◽

High Resistance ◽

Culex Quinquefasciatus ◽

Control Strategies ◽

Cuticular Hydrocarbon ◽

Control Measures ◽

High Frequencies ◽

The City ◽

Integrated Vector Control

AbstractCulex mosquitoes particularly Culex quinquefasciatus are important arboviral and filariasis vectors, however despite this important epidemiological role, there is still a paucity of data on their bionomics. The present study was undertaken to assess the insecticide resistance status of Cx. quinquefasciatus populations from four districts of Yaoundé (Cameroon). All Culex quinquefasciatus populations except one displayed high resistance to bendiocarb and malathion with mortalities ranging from 0 to 89% while high resistance intensity against both permethrin and deltamethrin was recorded. Molecular analyses revealed high frequencies of the ACE-1 G119S mutation (ranging from 0 to 33%) and kdr L1014F allele (ranging from 55 to 74%) in all Cx. quinquefasciatus populations. Significant overexpression was detected for cytochrome P450s genes CYP6AA7 and CYP6Z10, as well as for Esterase A and Esterase B genes. The total cuticular hydrocarbon content, a proxy of cuticular resistance, was significantly increased (compared to the S-lab strain) in one population. The study confirms strong insecticide resistance mediated by different mechanisms in Cx. quinquefasciatus populations from the city of Yaoundé. The expansion of insecticide resistance in Culex populations could affect the effectiveness of current vector control measures and stress the need for the implementation of integrated vector control strategies in urban settings.

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NIM1 Overexpression in Arabidopsis Potentiates Plant Disease Resistance and Results in Enhanced Effectiveness of Fungicides

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2001.14.9.1114 ◽

2001 ◽

Vol 14 (9) ◽

pp. 1114-1124 ◽

Cited By ~ 99

Author(s):

Leslie Friedrich ◽

Kay Lawton ◽

Robert Dietrich ◽

Michael Willits ◽

Rebecca Cade ◽

...

Keyword(s):

Disease Resistance ◽

Plant Disease Resistance ◽

Systemic Acquired Resistance ◽

Control Strategies ◽

Chemical Activation ◽

Acquired Resistance ◽

Wild Type ◽

Protein Levels ◽

Rapid Induction ◽

Dependent Signal

The NIM1 (for noninducible immunity, also known as NPR1) gene is required for the biological and chemical activation of systemic acquired resistance (SAR) in Arabidopsis. Overexpression of NIM1 in wild-type plants (hereafter referred to as NIM1 plants or lines) results in varying degrees of resistance to different pathogens. Experiments were performed to address the basis of the enhanced disease resistance responses seen in the NIM1 plants. The increased resistance observed in the NIM1 lines correlated with increased NIM1 protein levels and rapid induction of PR1 gene expression, a marker for SAR induction in Arabidopsis, following pathogen inoculation. Levels of salicylic acid (SA), an endogenous signaling molecule required for SAR induction, were not significantly increased compared with wild-type plants. SA was required for the enhanced resistance in NIM1 plants, however, suggesting that the effect of NIM1 overexpression is that plants are more responsive to SA or a SA-dependent signal. This hypothesis is supported by the heightened responsiveness that NIM1 lines exhibited to the SAR-inducing compound benzo(1,2,3)-thiadiazole-7-car-bothioic acid S-methyl ester. Furthermore, the increased efficacy of three fungicides was observed in the NIM1 plants, suggesting that a combination of transgenic and chemical approaches may lead to effective and durable disease-control strategies.

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Species diversity and insecticide resistance within the Anopheles hyrcanus group in Ubon Ratchathani Province, Thailand

Parasites & Vectors ◽

10.1186/s13071-020-04389-4 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Anchana Sumarnrote ◽

Hans J. Overgaard ◽

Vincent Corbel ◽

Kanutcharee Thanispong ◽

Theeraphap Chareonviriyaphap ◽

...

Keyword(s):

Insecticide Resistance ◽

Control Strategies ◽

Resistance Mechanism ◽

Abundant Species ◽

Malaria Vectors ◽

Pcr Assay ◽

Insecticide Susceptibility ◽

Human Landing ◽

Early Peak

Abstract Background Members of the Anopheles hyrcanus group have been incriminated as important malaria vectors. This study aims to identify the species and explore the insecticide susceptibility profile within the Anopheles hyrcanus group in Ubon Ratchathani Province, northeastern Thailand where increasing numbers of malaria cases were reported in 2014. Methods Between 2013 and 2015, five rounds of mosquito collections were conducted using human landing and cattle bait techniques during both the rainy and dry seasons. Anopheles mosquitoes were morphologically identified and their insecticide susceptibility status was investigated. Synergist bioassays were carried out with An. hyrcanus (s.l.) due to their resistance to all insecticides. An ITS2-PCR assay was conducted to identify to species the Hyrcanus group specimens. Results Out of 10,361 Anopheles females collected, representing 18 taxa in 2 subgenera, 71.8% were morphologically identified as belonging to the Hyrcanus Group (subgenus Anopheles), followed by An. barbirostris group (7.9%), An. nivipes (6.5%), An. philippinensis (5.9%) and the other 14 Anopheles species. Specimens of the Hyrcanus Group were more prevalent during the rainy season and were found to be highly zoophilic. Anopheles hyrcanus (s.l.) was active throughout the night, with an early peak of activity between 18:00 h and 21:00 h. ITS2-PCR assay conducted on 603 DNA samples from specimens within the Hyrcanus Group showed the presence of five sisters species. Anopheles peditaeniatus was the most abundant species (90.5%, n = 546), followed by An. nitidus (4.5%, n = 27), An. nigerrimus (4.3%, n = 26), An. argyropus (0.5%, n = 3), and An. sinensis (0.2%, n = 1). All An. hyrcanus (s.l.) specimens that were found resistant to insecticides (deltamethrin 0.05%, permethrin 0.75% and DDT 4% and synergist tests) belonged to An. peditaeniatus. The degree of resistance in An. peditaeniatus to each of these three insecticides was approximately 50%. Addition of PBO (Piperonyl butoxide), but not DEF (S.S.S-tributyl phosphotritioate), seemed to restore susceptibility, indicating a potential role of oxidases as a detoxifying enzyme resistance mechanism. Conclusions A better understanding of mosquito diversity related to host preference, biting activity and insecticide resistance status will facilitate the implementation of locally adapted vector control strategies.

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Transgenic Metarhizium rapidly kills mosquitoes in a malaria-endemic region of Burkina Faso

Science ◽

10.1126/science.aaw8737 ◽

2019 ◽

Vol 364 (6443) ◽

pp. 894-897 ◽

Cited By ~ 31

Author(s):

Brian Lovett ◽

Etienne Bilgo ◽

Souro Abel Millogo ◽

Abel Kader Ouattarra ◽

Issiaka Sare ◽

...

Keyword(s):

Insecticide Resistance ◽

Burkina Faso ◽

Malaria Control ◽

Natural Environment ◽

Chemical Control ◽

New Technologies ◽

Control Strategies ◽

Endemic Region ◽

Malaria Endemic Region ◽

A Site

Malaria control efforts require implementation of new technologies that manage insecticide resistance. Metarhizium pingshaense provides an effective, mosquito-specific delivery system for potent insect-selective toxins. A semifield trial in a MosquitoSphere (a contained, near-natural environment) in Soumousso, a region of Burkina Faso where malaria is endemic, confirmed that the expression of an insect-specific toxin (Hybrid) increased fungal lethality and the likelihood that insecticide-resistant mosquitoes would be eliminated from a site. Also, as Hybrid-expressing M. pingshaense is effective at very low spore doses, its efficacy lasted longer than that of the unmodified Metarhizium. Deployment of transgenic Metarhizium against mosquitoes could (subject to appropriate registration) be rapid, with products that could synergistically integrate with existing chemical control strategies to avert insecticide resistance.

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Anopheles metabolic proteins in malaria transmission, prevention and control: a review

Parasites & Vectors ◽

10.1186/s13071-020-04342-5 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Eunice Oluwatobiloba Adedeji ◽

Olubanke Olujoke Ogunlana ◽

Segun Fatumo ◽

Thomas Beder ◽

Yvonne Ajamma ◽

...

Keyword(s):

Insecticide Resistance ◽

Vector Control ◽

Malaria Transmission ◽

Control Strategies ◽

Parasite Development ◽

Potential Contribution ◽

Population Replacement ◽

Blood Digestion ◽

Significant Toxicity ◽

And Control

Abstract The increasing resistance to currently available insecticides in the malaria vector, Anopheles mosquitoes, hampers their use as an effective vector control strategy for the prevention of malaria transmission. Therefore, there is need for new insecticides and/or alternative vector control strategies, the development of which relies on the identification of possible targets in Anopheles. Some known and promising targets for the prevention or control of malaria transmission exist among Anopheles metabolic proteins. This review aims to elucidate the current and potential contribution of Anopheles metabolic proteins to malaria transmission and control. Highlighted are the roles of metabolic proteins as insecticide targets, in blood digestion and immune response as well as their contribution to insecticide resistance and Plasmodium parasite development. Furthermore, strategies by which these metabolic proteins can be utilized for vector control are described. Inhibitors of Anopheles metabolic proteins that are designed based on target specificity can yield insecticides with no significant toxicity to non-target species. These metabolic modulators combined with each other or with synergists, sterilants, and transmission-blocking agents in a single product, can yield potent malaria intervention strategies. These combinations can provide multiple means of controlling the vector. Also, they can help to slow down the development of insecticide resistance. Moreover, some metabolic proteins can be modulated for mosquito population replacement or suppression strategies, which will significantly help to curb malaria transmission.

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Nixalone is sufficient to convert femaleAedes aegyptiinto fertile males andmyo-sexis needed for male flight

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2001132117 ◽

2020 ◽

Vol 117 (30) ◽

pp. 17702-17709 ◽

Cited By ~ 5

Author(s):

Azadeh Aryan ◽

Michelle A. E. Anderson ◽

James K. Biedler ◽

Yumin Qi ◽

Justin M. Overcash ◽

...

Keyword(s):

Mosquito Control ◽

Control Strategies ◽

Reproductive Organs ◽

Dominant Male ◽

Chain Gene ◽

Sexually Dimorphic ◽

Wild Type ◽

Transgenic Lines ◽

Male Sex ◽

Male Specific

A dominant male-determining locus (M-locus) establishes the male sex (M/m) in the yellow fever mosquito,Aedes aegypti.Nix, a gene in the M-locus, was shown to be a male-determining factor (M factor) as somatic knockout ofNixled to feminized males (M/m) while transient expression ofNixresulted in partially masculinized females (m/m), with male reproductive organs but retained female antennae. It was not clear whether any of the other 29 genes in the 1.3-Mb M-locus are also needed for complete sex-conversion. Here, we report the generation of multiple transgenic lines that expressNixunder the control of its own promoter. Genetic and molecular analyses of these lines provided insights unattainable from previous transient experiments. We show that theNixtransgene alone, in the absence of the M-locus, was sufficient to convert females into males with all male-specific sexually dimorphic features and male-like gene expression. The converted m/m males are flightless, unable to perform the nuptial flight required for mating. However, they were able to father sex-converted progeny when presented with cold-anesthetized wild-type females. We show thatmyo-sex, a myosin heavy-chain gene also in the M-locus, was required for male flight as knockout ofmyo-sexrendered wild-type males flightless. We also show thatNix-mediated female-to-male conversion was 100% penetrant and stable over many generations. Therefore,Nixhas great potential for developing mosquito control strategies to reduce vector populations by female-to-male sex conversion, or to aid in a sterile insect technique that requires releasing only non-biting males.

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