Vector control measures failed to affect genetic structure of Aedes aegypti in a sentinel metropolitan area of Brazil

Since Aedes aegypti is considered as the major vector of dengue fever, development of strategies to accomplish improved vector control without much interference in the environment composition are more common. As phytochemicals are now in the run for achieving this goal, this review is a humble attempt to recognize the plant species and their larvicidal efficacy with their inhibitory action on the life cycle of the species of interest, that has been documented through various studies conducted till date. Here we also discuss the synergistic impact of a number of phytoextracts which will provide more efficient control measures for mosquito vectors. All these studies are an exploration for a risk-free vector control tactic to replace the current chemical insecticide application for the betterment of our nature.

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Insecticide resistance and genetic structure of Aedes aegypti populations from Rio de Janeiro State, Brazil

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0008492 ◽

2021 ◽

Vol 15 (2) ◽

pp. e0008492 ◽

Cited By ~ 1

Author(s):

Rafi Ur Rahman ◽

Luciano Veiga Cosme ◽

Monique Melo Costa ◽

Luana Carrara ◽

José Bento Pereira Lima ◽

...

Keyword(s):

Gene Flow ◽

Genetic Structure ◽

Aedes Aegypti ◽

Insecticide Resistance ◽

Vector Control ◽

Rio De Janeiro ◽

Control Program ◽

Positive Control ◽

World Health ◽

Janeiro State

Vector control largely relies on neurotoxic chemicals, and insecticide resistance (IR) directly threatens their effectiveness. In some cases, specific alleles cause IR, and knowledge of the genetic diversity and gene flow among mosquito populations is crucial to track their arrival, rise, and spread. Here we evaluated Aedes aegypti populations’ susceptibility status, collected in 2016 from six different municipalities of Rio de Janeiro state (RJ), to temephos, pyriproxyfen, malathion, and deltamethrin. We collected eggs of Ae. aegypti in Campos dos Goytacazes (Cgy), Itaperuna (Ipn), Iguaba Grande (Igg), Itaboraí (Ibr), Mangaratiba (Mgr), and Vassouras (Vsr). We followed the World Health Organization (WHO) guidelines and investigated the degree of susceptibility/resistance of mosquitoes to these insecticides. We used the Rockefeller strain as a susceptible positive control. We genotyped the V1016I and F1534C knockdown resistance (kdr) alleles using qPCR TaqMan SNP genotyping assay. Besides, with the use of Ae. aegypti SNP-chip, we performed genomic population analyses by genotyping more than 15,000 biallelic SNPs in mosquitoes from each population. We added previous data from populations from other countries to evaluate the ancestry of RJ populations. All RJ Ae. aegypti populations were susceptible to pyriproxyfen and malathion and highly resistant to deltamethrin. The resistance ratios for temephos was below 3,0 in Cgy, Ibr, and Igg populations, representing the lowest rates since IR monitoring started in this Brazilian region. We found the kdr alleles in high frequencies in all populations, partially justifying the observed resistance to pyrethroid. Population genetics analysis showed that Ae. aegypti revealed potential higher migration among some RJ localities and low genetic structure for most of them. Future population genetic studies, together with IR data in Ae aegypti on a broader scale, can help us predict the gene flow within and among the Brazilian States, allowing us to track the dynamics of arrival and changes in the frequency of IR alleles, and providing critical information to improving vector control program.

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Two Haplotypes of Aedes aegypti Detected by ND4 Mitochondrial Marker in Three Regions of Ecuador

Insects ◽

10.3390/insects12030200 ◽

2021 ◽

Vol 12 (3) ◽

pp. 200

Author(s):

Patricio Ponce ◽

Sofía Muñoz-Tobar ◽

Andrés Carrazco-Montalvo ◽

Stephany D. Villota ◽

Josefina Coloma ◽

...

Keyword(s):

Genetic Structure ◽

Aedes Aegypti ◽

Vector Control ◽

Control Strategies ◽

Mitochondrial Gene ◽

Control Programs ◽

Key Factor ◽

Tropical Areas ◽

The One ◽

Haplotype 1

Aedes aegypti, also known as the yellow fever mosquito, is the main vector of several arboviruses. In Ecuador, dengue and chikungunya are the most prevalent mosquito-borne diseases. Hence, there is a need to understand the population dynamics and genetic structure of the vector in tropical areas for a better approach towards effective vector control programs. This study aimed to assess the genetic diversity of Ae. aegypti, through the analyses of the mitochondrial gene ND4, using a combination of phylogenetic and population genetic structure from 17 sites in Ecuador. Results showed two haplotypes in the Ecuadorian populations of Ae. aegypti. Haplotype 1 was closely related to Ae. aegypti reported from America, Asia, and West Africa. Haplotype 2 was only related to samples from America. The sampled vectors from the diverse localities showed low nucleotide diversity (π = 0–0.01685) and genetic differentiation (FST = 0.152). AMOVA analyses indicated that most of the variation (85–91%) occurred within populations, suggesting that geographical barriers have little effect on the genetic structure of Ecuadorian populations of Ae. aegypti. These results agree with the one main population (K = 1) detected by Structure. Vector genetic identity may be a key factor in the planning of vector control strategies.

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Abundance and Updated Distribution of Aedes aegypti (Diptera: Culicidae) in Cabo Verde Archipelago: A Neglected Threat to Public Health

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17041291 ◽

2020 ◽

Vol 17 (4) ◽

pp. 1291

Author(s):

Silvânia Da Veiga Leal ◽

Isaias Baptista Fernandes Varela ◽

Aderitow Augusto Lopes Gonçalves ◽

Davidson Daniel Sousa Monteiro ◽

Celivianne Marisia Ramos de Sousa ◽

...

Keyword(s):

Public Health ◽

Aedes Aegypti ◽

Vector Control ◽

Disease Outbreaks ◽

Control Measures ◽

Domestic Water ◽

Breeding Sites ◽

Cabo Verde ◽

Larval Survey ◽

Vector Borne

Background: Mosquito-borne viruses, such as Zika, dengue, yellow fever, and chikungunya, are important causes of human diseases nearly worldwide. The greatest health risk for arboviral disease outbreaks is the presence of the most competent and highly invasive domestic mosquito, Aedes aegypti. In Cabo Verde, two recent arbovirus outbreaks were reported, a dengue outbreak in 2009, followed by a Zika outbreak in 2015. This study is the first entomological survey for Ae. aegypti that includes all islands of Cabo Verde archipelago, in which we aim to evaluate the actual risk of vector-borne arboviruses as a continuous update of the geographical distribution of this species. Methods: In order to assess its current distribution and abundance, we undertook a mosquito larval survey in the nine inhabited islands of Cabo Verde from November 2018 to May 2019. Entomological larval survey indices were calculated, and the abundance analyzed. We collected and identified 4045 Ae. aegypti mosquitoes from 264 positive breeding sites in 22 municipalities and confirmed the presence of Ae. aegypti in every inhabited island. Results: Water drums were found to be the most prevalent containers (n = 3843; 62.9%), but puddles (n = 27; 0.4%) were the most productive habitats found. The overall average of the House, Container, and Breteau larval indices were 8.4%, 4.4%, and 10.9, respectively. However, 15 out of the 22 municipalities showed that the Breteau Index was above the epidemic risk threshold. Conclusion: These results suggest that if no vector control measures are considered to be in place, the risk of new arboviral outbreaks in Cabo Verde is high. The vector control strategy adopted must include measures of public health directed to domestic water storage and management.

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The pharmacokinetics and drug-drug interactions of ivermectin in Aedes aegypti mosquitoes

PLoS Pathogens ◽

10.1371/journal.ppat.1009382 ◽

2021 ◽

Vol 17 (3) ◽

pp. e1009382

Author(s):

Urs Duthaler ◽

Michael Weber ◽

Lorenz Hofer ◽

Carlos Chaccour ◽

Marta Maia ◽

...

Keyword(s):

Aedes Aegypti ◽

Drug Interactions ◽

Vector Control ◽

Elimination Rate ◽

Control Measures ◽

Piperonyl Butoxide ◽

Pharmacokinetic Parameters ◽

Lag Phase ◽

Control Female ◽

Drug Concentrations

Mosquitoes are vectors of major diseases such as dengue fever and malaria. Mass drug administration of endectocides to humans and livestock is a promising complementary approach to current insecticide-based vector control measures. The aim of this study was to establish an insect model for pharmacokinetic and drug-drug interaction studies to develop sustainable endectocides for vector control. FemaleAedes aegyptimosquitoes were fed with human blood containing either ivermectin alone or ivermectin in combination with ketoconazole, rifampicin, ritonavir, or piperonyl butoxide. Drug concentrations were quantified by LC-MS/MS at selected time points post-feeding. Primary pharmacokinetic parameters and extent of drug-drug interactions were calculated by pharmacometric modelling. Lastly, the drug effect of the treatments was examined. The mosquitoes could be dosed with a high precision (%CV: ≤13.4%) over a range of 0.01–1 μg/ml ivermectin without showing saturation (R2: 0.99). The kinetics of ivermectin were characterised by an initial lag phase of 18.5 h (CI90%: 17.0–19.8 h) followed by a slow zero-order elimination rate of 5.5 pg/h (CI90%: 5.1–5.9 pg/h). By contrast, ketoconazole, ritonavir, and piperonyl butoxide were immediately excreted following first order elimination, whereas rifampicin accumulated over days in the mosquitoes. Ritonavir increased the lag phase of ivermectin by 11.4 h (CI90%: 8.7–14.2 h) resulting in an increased exposure (+29%) and an enhanced mosquitocidal effect. In summary, this study shows that the pharmacokinetics of drugs can be investigated and modulated in anAe.aegyptianimal model. This may help in the development of novel vector-control interventions and further our understanding of toxicology in arthropods.

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Temporal and Spatial Blood Feeding Patterns of Urban Mosquitoes in the San Juan Metropolitan Area, Puerto Rico

Insects ◽

10.3390/insects12020129 ◽

2021 ◽

Vol 12 (2) ◽

pp. 129

Author(s):

Matthew W. Hopken ◽

Limarie J. Reyes-Torres ◽

Nicole Scavo ◽

Antoinette J. Piaggio ◽

Zaid Abdo ◽

...

Keyword(s):

Puerto Rico ◽

Aedes Aegypti ◽

Metropolitan Area ◽

Culex Quinquefasciatus ◽

Urban Ecosystems ◽

Life Cycles ◽

Pathogen Transmission ◽

San Juan ◽

Vertebrate Species ◽

Blood Meals

Urban ecosystems are a patchwork of habitats that host a broad diversity of animal species. Insects comprise a large portion of urban biodiversity which includes many pest species, including those that transmit pathogens. Mosquitoes (Diptera: Culicidae) inhabit urban environments and rely on sympatric vertebrate species to complete their life cycles, and in this process transmit pathogens to animals and humans. Given that mosquitoes feed upon vertebrates, they can also act as efficient samplers that facilitate detection of vertebrate species that utilize urban ecosystems. In this study, we analyzed DNA extracted from mosquito blood meals collected temporally in multiple neighborhoods of the San Juan Metropolitan Area, Puerto Rico to evaluate the presence of vertebrate fauna. DNA was collected from 604 individual mosquitoes that represented two common urban species, Culex quinquefasciatus (n = 586) and Aedes aegypti (n = 18). Culex quinquefasciatus fed on 17 avian taxa (81.2% of blood meals), seven mammalian taxa (17.9%), and one reptilian taxon (0.85%). Domestic chickens dominated these blood meals both temporally and spatially, and no statistically significant shift from birds to mammals was detected. Aedes aegypti blood meals were from a less diverse group, with two avian taxa (11.1%) and three mammalian taxa (88.9%) identified. The blood meals we identified provided a snapshot of the vertebrate community in the San Juan Metropolitan Area and have potential implications for vector-borne pathogen transmission.

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Integration of municipal state, society, and university efforts for sanitary risk prevention associated with Aedes aegypti mosquito in the metropolitan area of Buenos Aires, Argentina

Tropical Medicine & International Health ◽

10.1111/tmi.13581 ◽

2021 ◽

Author(s):

Carlos Alberto Ruggerio ◽

Giselle Andrea Querejeta ◽

Katherine Belen Conicelli ◽

Rubén Jorge Lombardo

Keyword(s):

Aedes Aegypti ◽

Metropolitan Area ◽

Buenos Aires ◽

Risk Prevention

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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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Predicting Aedes aegypti infestation using landscape and thermal features

Scientific Reports ◽

10.1038/s41598-020-78755-8 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Camila Lorenz ◽

Marcia C. Castro ◽

Patricia M. P. Trindade ◽

Maurício L. Nogueira ◽

Mariana de Oliveira Lage ◽

...

Keyword(s):

Remote Sensing ◽

Aedes Aegypti ◽

Vector Control ◽

Land Surface ◽

Urban Areas ◽

Negative Binomial ◽

Control Strategies ◽

Winter Season ◽

Landsat 8 ◽

Thermal Features

AbstractIdentifying Aedes aegypti breeding hotspots in urban areas is crucial for the design of effective vector control strategies. Remote sensing techniques offer valuable tools for mapping habitat suitability. In this study, we evaluated the association between urban landscape, thermal features, and mosquito infestations. Entomological surveys were conducted between 2016 and 2019 in Vila Toninho, a neighborhood of São José do Rio Preto, São Paulo, Brazil, in which the numbers of adult female Ae. aegypti were recorded monthly and grouped by season for three years. We used data from 2016 to 2018 to build the model and data from summer of 2019 to validate it. WorldView-3 satellite images were used to extract land cover classes, and land surface temperature data were obtained using the Landsat-8 Thermal Infrared Sensor (TIRS). A multilevel negative binomial model was fitted to the data, which showed that the winter season has the greatest influence on decreases in mosquito abundance. Green areas and pavements were negatively associated, and a higher cover of asbestos roofs and exposed soil was positively associated with the presence of adult females. These features are related to socio-economic factors but also provide favorable breeding conditions for mosquitos. The application of remote sensing technologies has significant potential for optimizing vector control strategies, future mosquito suppression, and outbreak prediction.

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