scholarly journals Spatial variation in the frequency of knockdown resistance genotypes in Florida Aedes aegypti populations

2019 ◽  
Author(s):  
Stephanie Jane Mundis ◽  
Alden S. Estep ◽  
Christy M. Waits ◽  
Sadie J. Ryan
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Mosquito Species ◽  
Explanatory Power ◽  
Beta Regression ◽  
Spatial Error ◽  
Resistant Variant ◽  
Pyrethroid Insecticides ◽  
Use Factors

Abstract BackgroundThe development of insecticide resistance in disease-vectoring mosquito species can lead to vector control failure and disease resurgence. However, insecticide applications remain an essential public health intervention. In Florida, insecticide resistance in Aedes aegypti, an anthropophilic mosquito species capable of transmitting dengue, chikungunya, and Zika virus, is a major concern. Understanding the location, scale, and driving factors of insecticide resistance can enhance the ability of vector control organizations to target populations effectively.MethodsWe used previously collected data on frequencies of mutations that confer resistance to commonly used pyrethroid insecticides in Aedes aegypti specimens from 62 sites distributed across 18 counties in Florida. To determine the scale of clustering for the most resistant variant, we used a Ripley’s K function. We also used a spatial scanning statistic technique to identify the locations of clusters where higher than expected frequencies of susceptible or resistant mosquitoes occurred. We then tested for associations between landscape, demographic, and insecticide-use factors using a beta regression modelling approach and evaluated the effect of spatial lag and spatial error terms on overall explanatory power of these models. ResultsThe scale at which maximum clustering of the most resistant variant occurs is approximately 20 kilometers. We identified statistically significant clusters of resistance in several coastal cities, although some of these clusters were near significant clusters of susceptible mosquitoes, indicating selection pressures vary at the local scale. Vegetation density, distance from roads, and pyrethroid-use by vector control districts were consistently significant predictors of insecticide resistance frequency in the top-performing beta regression models, although pyrethroid-use surprisingly had a negatively associated with resistance. The incorporation of spatial lags resulted in improvements to the fit and explanatory power of the models, indicating an underlying diffusion process likely explains some of the spatial patterns in resistance observed.ConclusionsThe genetic mutations that confer resistance to pyrethroids in Aedes aegpyti mosquitoes in Florida exhibit spatial autocorrelation and patterns that can be partially explained by landscape and insecticide-use factors. Further work at local scales should be able to identify the mechanisms by which these variables influence the outcome of resistance.

scholarly journals Spatial variation in the frequency of knockdown resistance genotypes in Florida Aedes aegypti populations

2020 ◽  
Author(s):  
Stephanie Jane Mundis ◽  
Alden S. Estep ◽  
Christy M. Waits ◽  
Sadie J. Ryan
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Mosquito Species ◽  
Explanatory Power ◽  
Beta Regression ◽  
Spatial Error ◽  
Resistant Variant ◽  
Pyrethroid Insecticides ◽  
Use Factors

Abstract Background The development of insecticide resistance in disease-vectoring mosquito species can lead to vector control failure and disease resurgence. However, insecticide applications remain an essential public health intervention. In Florida, insecticide resistance in Aedes aegypti , an anthropophilic mosquito species capable of transmitting dengue, chikungunya, and Zika virus, is a major concern. Understanding the location, scale, and driving factors of insecticide resistance can enhance the ability of vector control organizations to target populations effectively.Methods We used previously collected data on frequencies of mutations that confer resistance to commonly used pyrethroid insecticides in Aedes aegypti specimens from 62 sites distributed across 18 counties in Florida. To determine the scale of clustering for the most resistant variant, we used a Ripley’s K function. We also used a spatial scanning statistic technique to identify the locations of clusters where higher than expected frequencies of susceptible or resistant mosquitoes occurred. We then tested for associations between landscape, demographic, and insecticide-use factors using a beta regression modelling approach and evaluated the effect of spatial lag and spatial error terms on overall explanatory power of these models.Results The scale at which maximum clustering of the most resistant variant occurs is approximately 20 kilometers. We identified statistically significant clusters of resistance in several coastal cities, although some of these clusters were near significant clusters of susceptible mosquitoes, indicating selection pressures vary at the local scale. Vegetation density, distance from roads, and pyrethroid-use by vector control districts were consistently significant predictors of insecticide resistance frequency in the top-performing beta regression models, although pyrethroid-use surprisingly had a negatively associated with resistance. The incorporation of spatial lags resulted in improvements to the fit and explanatory power of the models, indicating an underlying diffusion process likely explains some of the spatial patterns in resistance observed.Conclusions The genetic mutations that confer resistance to pyrethroids in Aedes aegpyti mosquitoes in Florida exhibit spatial autocorrelation and patterns that can be partially explained by landscape and insecticide-use factors. Further work at local scales should be able to identify the mechanisms by which these variables influence the outcome of resistance.

scholarly journals Spatial variation in the frequency of knockdown resistance genotypes in Florida Aedes aegypti populations

2020 ◽  
Author(s):  
Stephanie Jane Mundis ◽  
Alden S. Estep ◽  
Christy M. Waits ◽  
Sadie J. Ryan
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Mosquito Species ◽  
Explanatory Power ◽  
Beta Regression ◽  
Knockdown Resistance ◽  
Resistant Variant ◽  
Pyrethroid Insecticides ◽  
Use Factors

Abstract Background The development of insecticide resistance in disease-vectoring mosquito species can lead to vector control failure and disease resurgence. However, insecticide applications remain an essential public health intervention. In Florida, insecticide resistance in Aedes aegypti , an anthropophilic mosquito species capable of transmitting dengue, chikungunya, and Zika virus, is a major concern. Understanding the location, scale, and driving factors of insecticide resistance can enhance the ability of vector control organizations to target populations effectively. Methods We used previously collected data on frequencies of mutations that confer resistance to commonly used pyrethroid insecticides in Aedes aegypti specimens from 62 sites distributed across 18 counties in Florida. To determine the scale of clustering for the most resistant variant, we used a Ripley’s K function. We also used a spatial scanning statistic technique to identify the locations of clusters where higher than expected frequencies of susceptible or resistant mosquitoes occurred. We then tested for associations between landscape, demographic, and insecticide-use factors using a beta regression modelling approach and evaluated the effect of spatial lag and spatial error terms on overall explanatory power of these models. Results The scale at which maximum clustering of the most resistant variant occurs is approximately 20 kilometers. We identified statistically significant clusters of genotypes associated with resistancein several coastal cities, although some of these clusters were near significant clusters of susceptible mosquitoes, indicating selection pressures vary at the local scale. Vegetation density, distance from roads, and pyrethroid-use by vector control districts were consistently significant predictors of knockdown resistance genotype frequency in the top-performing beta regression models, although pyrethroid-use surprisingly had a negatively associated with resistance. The incorporation of spatial lags resulted in improvements to the fit and explanatory power of the models, indicating an underlying diffusion process likely explains some of the spatial patterns observed. Conclusions The genetic mutations that confer resistance to pyrethroids in Aedes aegpyti mosquitoes in Florida exhibit spatial autocorrelation and patterns that can be partially explained by landscape and insecticide-use factors. Further work at local scales should be able to identify the mechanisms by which these variables influence selection for alleles associated with resistance.

scholarly journals Spatial variation in the frequency of knockdown resistance genotypes in Florida Aedes aegypti populations

2020 ◽  
Author(s):  
Stephanie Jane Mundis ◽  
Alden S. Estep ◽  
Christy M. Waits ◽  
Sadie J. Ryan
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Mosquito Species ◽  
Explanatory Power ◽  
Beta Regression ◽  
Knockdown Resistance ◽  
Resistant Variant ◽  
Pyrethroid Insecticides ◽  
Use Factors

Abstract Background The development of insecticide resistance in disease-vectoring mosquito species can lead to vector control failure and disease resurgence. However, insecticide applications remain an essential public health intervention. In Florida, insecticide resistance in Aedes aegypti , an anthropophilic mosquito species capable of transmitting dengue, chikungunya, and Zika virus, is a major concern. Understanding the location, scale, and driving factors of insecticide resistance can enhance the ability of vector control organizations to target populations effectively. Methods We used previously collected data on frequencies of mutations that confer resistance to commonly used pyrethroid insecticides in Aedes aegypti specimens from 62 sites distributed across 18 counties in Florida. To determine the scale of clustering for the most resistant variant, we used a Ripley’s K function. We also used a spatial scanning statistic technique to identify the locations of clusters where higher than expected frequencies of susceptible or resistant mosquitoes occurred. We then tested for associations between landscape, demographic, and insecticide-use factors using a beta regression modelling approach and evaluated the effect of spatial lag and spatial error terms on overall explanatory power of these models. Results The scale at which maximum clustering of the most resistant variant occurs is approximately 20 kilometers. We identified statistically significant clusters of genotypes associated with resistancein several coastal cities, although some of these clusters were near significant clusters of susceptible mosquitoes, indicating selection pressures vary at the local scale. Vegetation density, distance from roads, and pyrethroid-use by vector control districts were consistently significant predictors of knockdown resistance genotype frequency in the top-performing beta regression models, although pyrethroid-use surprisingly had a negatively associated with resistance. The incorporation of spatial lags resulted in improvements to the fit and explanatory power of the models, indicating an underlying diffusion process likely explains some of the spatial patterns observed. Conclusions The genetic mutations that confer resistance to pyrethroids in Aedes aegpyti mosquitoes in Florida exhibit spatial autocorrelation and patterns that can be partially explained by landscape and insecticide-use factors. Further work at local scales should be able to identify the mechanisms by which these variables influence selection for alleles associated with resistance.

scholarly journals Spatial variation in the frequency of knockdown resistance genotypes in Florida Aedes aegypti populations

2020 ◽  
Author(s):  
Stephanie Jane Mundis ◽  
Alden S. Estep ◽  
Christy M. Waits ◽  
Sadie J. Ryan
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Mosquito Species ◽  
Explanatory Power ◽  
Beta Regression ◽  
Knockdown Resistance ◽  
Resistant Variant ◽  
Pyrethroid Insecticides ◽  
Use Factors

Abstract Background The development of insecticide resistance in disease-vectoring mosquito species can lead to vector control failure and disease resurgence. However, insecticide applications remain an essential public health intervention. In Florida, insecticide resistance in Aedes aegypti , an anthropophilic mosquito species capable of transmitting dengue, chikungunya, and Zika virus, is a major concern. Understanding the location, scale, and driving factors of insecticide resistance can enhance the ability of vector control organizations to target populations effectively. Methods We used previously collected data on frequencies of mutations that confer resistance to commonly used pyrethroid insecticides in Aedes aegypti specimens from 62 sites distributed across 18 counties in Florida. To determine the scale of clustering for the most resistant variant, we used a Ripley’s K function. We also used a spatial scanning statistic technique to identify the locations of clusters where higher than expected frequencies of susceptible or resistant mosquitoes occurred. We then tested for associations between landscape, demographic, and insecticide-use factors using a beta regression modelling approach and evaluated the effect of spatial lag and spatial error terms on overall explanatory power of these models. Results The scale at which maximum clustering of the most resistant variant occurs is approximately 20 kilometers. We identified statistically significant clusters of genotypes associated with resistancein several coastal cities, although some of these clusters were near significant clusters of susceptible mosquitoes, indicating selection pressures vary at the local scale. Vegetation density, distance from roads, and pyrethroid-use by vector control districts were consistently significant predictors of knockdown resistance genotype frequency in the top-performing beta regression models, although pyrethroid-use surprisingly had a negatively associated with resistance. The incorporation of spatial lags resulted in improvements to the fit and explanatory power of the models, indicating an underlying diffusion process likely explains some of the spatial patterns observed. Conclusions The genetic mutations that confer resistance to pyrethroids in Aedes aegpyti mosquitoes in Florida exhibit spatial autocorrelation and patterns that can be partially explained by landscape and insecticide-use factors. Further work at local scales should be able to identify the mechanisms by which these variables influence selection for alleles associated with resistance.

scholarly journals Insecticide resistance in dengue vectors from hotspots in Selangor, Malaysia

2021 ◽  
Vol 15 (3) ◽  
pp. e0009205
Author(s):  
Rosilawati Rasli ◽  
Yoon Ling Cheong ◽  
M. Khairuddin Che Ibrahim ◽  
Siti Futri Farahininajua Fikri ◽  
Rusydi Najmuddin Norzali ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Aedes Albopictus ◽  
World Health ◽  
Dengue Vector ◽  
Organophosphate Insecticide ◽  
Potential Threat ◽  
Pyrethroid Insecticides ◽  
Dengue Vector Control

Background In Malaysia, dengue remains a top priority disease and usage of insecticides is the main method for dengue vector control. Limited baseline insecticide resistance data in dengue hotspots has prompted us to conduct this study. The present study reports the use of a map on the insecticide susceptibility status of Aedes aegypti and Aedes albopictus to provide a quick visualization and overview of the distribution of insecticide resistance. Method and results The insecticide resistance status of Aedes populations collected from 24 dengue hotspot areas from the period of December 2018 until June 2019 was proactively monitored using the World Health Organization standard protocol for adult and larval susceptibility testing was conducted, together with elucidation of the mechanisms involved in observed resistance. For resistance monitoring, susceptibility to three adulticides (permethrin, deltamethrin, and malathion) was tested, as well as susceptibility to the larvicide, temephos. Data showed significant resistance to both deltamethrin and permethrin (pyrethroid insecticides), and to malathion (organophosphate insecticide) in all sampled Aedes aegypti populations, while variable resistance patterns were found in the sampled Aedes albopictus populations. Temephos resistance was observed when larvae were tested using the diagnostic dosage of 0.012mg/L but not at the operational dosage of 1mg/L for both species. Conclusion The present study highlights evidence of a potential threat to the effectiveness of insecticides currently used in dengue vector control, and the urgent requirement for insecticide resistance management to be integrated into the National Dengue Control Program.

scholarly journals Plant Natural Products for the Control of Aedes aegypti: The Main Vector of Important Arboviruses

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3484 ◽  
Author(s):  
Maíra Rosato Silveiral Silvério ◽  
Laila Salmen Espindola ◽  
Norberto Peporine Lopes ◽  
Paulo Cézar Vieira
Keyword(s):  
Natural Products ◽  
Secondary Metabolites ◽  
Aedes Aegypti ◽  
Vector Control ◽  
Chemical Constituents ◽  
Mosquito Species ◽  
Mechanisms Of Action ◽  
Control Applications ◽  
Lower Toxicity ◽  
Plant Natural Products

The mosquito species Aedes aegypti is one of the main vectors of arboviruses, including dengue, Zika and chikungunya. Considering the deficiency or absence of vaccines to prevent these diseases, vector control remains an important strategy. The use of plant natural product-based insecticides constitutes an alternative to chemical insecticides as they are degraded more easily and are less harmful to the environment, not to mention their lower toxicity to non-target insects. This review details plant species and their secondary metabolites that have demonstrated insecticidal properties (ovicidal, larvicidal, pupicidal, adulticidal, repellent and ovipositional effects) against the mosquito, together with their mechanisms of action. In particular, essential oils and some of their chemical constituents such as terpenoids and phenylpropanoids offer distinct advantages. Thiophenes, amides and alkaloids also possess high larvicidal and adulticidal activities, adding to the wealth of plant natural products with potential in vector control applications.

scholarly journals Co-occurrence of kdr Mutations V1016I and F1534C and Its Association With Phenotypic Resistance to Pyrethroids in Aedes aegypti (Diptera: Culicidae) Populations From Costa Rica

2019 ◽  
Vol 57 (3) ◽  
pp. 830-836
Author(s):  
Aryana Zardkoohi ◽  
David Castañeda ◽  
Juan C Lol ◽  
Carmen Castillo ◽  
Francisco Lopez ◽  
...  
Keyword(s):  
Costa Rica ◽  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Strong Association ◽  
Resistance Management ◽  
Management Plan ◽  
Costa Rican ◽  
Mosquito Vector ◽  
Phenotypic Resistance

Abstract Aedes aegypti (Linnaeus, 1762) is considered the most important mosquito vector species for several arboviruses (e.g., dengue, chikungunya, Zika) in Costa Rica. The primary strategy for the control and prevention of Aedes-borne diseases relies on insecticide-based vector control. However, the emergence of insecticide resistance in the mosquito populations presents a significant threat to these prevention actions. The characterization of the mechanisms driving the insecticide resistance in Ae. aegypti is vital for decision making in vector control programs. Therefore, we analyzed the voltage-gated sodium channel (VGSC) gene for the presence of the V1016I and F1534C kdr mutations in Ae. aegypti populations from Puntarenas and Limon provinces, Costa Rica. The CDC bottle bioassays showed that both Costa Rican Ae. aegypti populations were resistant to permethrin and deltamethrin. In the case of kdr genotyping, results revealed the co-occurrence of V1016I and F1534C mutations in permethrin and deltamethrin-resistant populations, as well as the fixation of the 1534C allele. A strong association between these mutations and permethrin and deltamethrin resistance was found in Puntarenas. Limon did not show this association; however, our results indicate that the Limon population analyzed is not under the same selective pressure as Puntarenas for the VGSC gene. Therefore, our findings make an urgent call to expand the knowledge about the insecticide resistance status and mechanisms in the Costa Rican populations of Ae. aegypti, which must be a priority to develop an effective resistance management plan.

scholarly journals Co-occurrence of kdr mutations V1016I and F1534C in pyrethroid-resistant Aedes aegypti (Diptera: Culicidae) populations from Costa Rica

2019 ◽  
Author(s):  
Aryana Zardkoohi ◽  
David Castañeda ◽  
Carmen Castillo ◽  
Juan C Lol ◽  
Francisco Lopez ◽  
...  
Keyword(s):  
Costa Rica ◽  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Resistance Management ◽  
Management Plan ◽  
Costa Rican ◽  
Mosquito Vector ◽  
Control Programs ◽  
Control And Prevention

AbstractAedes aegypti (Linnaeus, 1762) is considered the most important mosquito vector species for several arboviruses (e.g., dengue, chikungunya, Zika) in Costa Rica. The main strategy for the control and prevention of Aedes-borne diseases relies on insecticide-based vector control. However, the emergence of insecticide resistance in the mosquito populations present a big threat for the prevention actions. The characterization of the mechanisms driving the insecticide resistance in Ae. aegypti are vital for decision making in vector control programs. Therefore, we analyzed the voltage-gated sodium channel gene for the presence of the V1016I and F1534C kdr mutations in pyrethroid-resistant Ae. aegypti populations from Puntarenas and Limon provinces, Costa Rica. The CDC bottle bioassays showed that both Costa Rican Ae. aegypti populations were resistant to permethrin and deltamethrin. In the case of kdr genotyping, results revealed the co-occurrence of V1016I and F1534C mutations in permethrin and deltamethrin-resistant populations, as well as the fixation of the 1534C allele. Therefore, our findings make an urgent call to expand the knowledge about the insecticide resistance status and mechanisms in the Costa Rican populations of Ae. aegypti which must be a priority to develop an effective resistance management plan.

scholarly journals Evaluation of the resistance to insecticides in Aedes aegypti, transmitter of dengue, in Latin America

2020 ◽  
Vol 8 (15) ◽  
pp. 23-28
Author(s):  
Amparo Gabriela Hernández Ramos
Keyword(s):  
Infectious Disease ◽  
Latin America ◽  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Latin American ◽  
Female Mosquito ◽  
The World ◽  
Different Seasons ◽  
Latin American Countries

Dengue is an infectious disease with high rates of morbidity and mortality, transmitted by the bite of the female mosquito of the genus Aedes aegypti, vector distributed in tropical and subtropical areas throughout the world. America is one of the most affected regions. This vector is controlled through insecticides that due to its constant use in populations, a resistance phenomenon has been produced. The objective of this review is to identify the situation of insecticide resistance in populations of Aedes aegypti in Latin American countries. In this region, several insecticides have been used for vector control; in the last 10 years insecticides of the pyrethroid and organophosphorus group have been used as adulticides for the control of the mosquito, conditioning resistance. Some insecticides such as organophosphates and deltamethrin, despite of not being intensively used in Latin American countries, also show resistance. Improvements in vector control are required, including the rotation of the insecticides during the different seasons, as well as innovating techniques and forms of vector control

scholarly journals Frequency of kdr mutations in the voltage-sensitive sodium channel (VSSC) gene in Aedes aegypti from Yogyakarta and implications for Wolbachia-infected mosquito trials

2020 ◽  
Author(s):  
Juli R. Wuliandari ◽  
Ary A. Hoffmann ◽  
Warsito Tantowijoyo ◽  
Nancy M. Endersby-Harshman
Keyword(s):  
Aedes Aegypti ◽  
Inner City ◽  
Insecticide Resistance ◽  
Sodium Channel ◽  
Pyrethroid Resistance ◽  
Infected Mosquito ◽  
Simultaneous Occurrence ◽  
Pyrethroid Insecticides ◽  
Background Population ◽  
Homozygous Mutant

Abstract Background : In the inner city of Yogyakarta, Indonesia, insecticide resistance is expected in the main dengue vector, Aedes aegypti , because of the intensive local application of pyrethroid insecticides. However, detailed information about the nature of resistance in this species is required to assist the release of Wolbachia mosquitoes in a dengue control program so that we can ensure that insecticide resistance in the strain of Ae. aegypti being released matches that of the background population. Methods: High-resolution melt genotyping was used to screen for kdr mutations associated with pyrethroid resistance in the voltage-sensitive sodium channel (V SSC ) gene in Ae. aegypti of some areas in the inner city of Yogyakarta. Results: The results show that the V1016G mutation predominated, with individuals homozygous for the 1016G allele at a frequency of 82.1% and the mutant allele G at a frequency of 92%. Two patterns of co-occurrence of mutations were detected in this study, homozygous individuals V1016G/S989P; and heterozygous individuals V1016G/F1534C/S989P. We found the simultaneous occurrence of kdr mutations V1016G and F1534C at all collection sites, but not within individual mosquitoes. Homozygous mutants at locus 1016 were homozygous wildtype at locus 1534 and vice versa, and heterozygous V1016G were also heterozygous for F1534C. The most common tri-locus genotype co-occurrences were homozygous mutant 1016GG and homozygous wild-type FF1534, combined with homozygous mutant 989PP (GG/FF/PP) at a frequency of 38.28%. Conclusions: Given the relatively small differences in frequency of resistance alleles across the city area, locality variations in resistance should have minor implications for the success of Wolbachia mosquito trials being undertaken in the Yogyakarta area.

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