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

Insects ◽  
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.

scholarly journals Predicting Aedes aegypti infestation using landscape and thermal features

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.

scholarly journals Intracellular Interactions Between Arboviruses and Wolbachia in Aedes aegypti

2021 ◽  
Vol 11 ◽  
Author(s):  
Jerica Isabel L. Reyes ◽  
Yasutsugu Suzuki ◽  
Thaddeus Carvajal ◽  
Maria Nilda M. Muñoz ◽  
Kozo Watanabe
Keyword(s):  
Aedes Aegypti ◽  
Vector Control ◽  
Host Species ◽  
Control Strategies ◽  
Cytoskeletal Proteins ◽  
Cellular Interactions ◽  
Cellular Mechanisms ◽  
Cellular Regeneration ◽  
Release Program ◽  
Human Infections

Aedes aegypti is inherently susceptible to arboviruses. The geographical expansion of this vector host species has led to the persistence of Dengue, Zika, and Chikungunya human infections. These viruses take advantage of the mosquito’s cell to create an environment conducive for their growth. Arboviral infection triggers transcriptomic and protein dysregulation in Ae. aegypti and in effect, host antiviral mechanisms are compromised. Currently, there are no existing vaccines able to protect human hosts from these infections and thus, vector control strategies such as Wolbachia mass release program is regarded as a viable option. Considerable evidence demonstrates how the presence of Wolbachia interferes with arboviruses by decreasing host cytoskeletal proteins and lipids essential for arboviral infection. Also, Wolbachia strengthens host immunity, cellular regeneration and causes the expression of microRNAs which could potentially be involved in virus inhibition. However, variation in the magnitude of Wolbachia’s pathogen blocking effect that is not due to the endosymbiont’s density has been recently reported. Furthermore, the cellular mechanisms involved in this phenotype differs depending on Wolbachia strain and host species. This prompts the need to explore the cellular interactions between Ae. aegypti-arboviruses-Wolbachia and how different Wolbachia strains overall affect the mosquito’s cell. Understanding what happens at the cellular and molecular level will provide evidence on the sustainability of Wolbachia vector control.

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 Intracellular Interactions between Arboviruses and Wolbachia in Aedes aegypti

2021 ◽  
Author(s):  
Jerica Isabel Reyes ◽  
Yasutsugu Suzuki ◽  
Thaddeus Carvajal ◽  
Maria Nilda Muñoz ◽  
Kozo Watanabe
Keyword(s):  
Aedes Aegypti ◽  
Vector Control ◽  
Control Strategies ◽  
Host Responses ◽  
Cellular Interactions ◽  
Viral Inhibition ◽  
Cellular Mechanisms ◽  
Release Program ◽  
Human Infections ◽  
Cellular Components

Aedes aegypti is inherently susceptible to arboviruses. The geographical expansion of this vector host species has led to the persistence of Dengue, Zika and Chikungunya human infections. These viruses take advantage of the mosquito’s cell to create an environment conducive for their growth. Arboviral infection triggers transcriptomic and protein dysregulation in Ae. aegypti and in effect, host antiviral mechanisms are compromised. Currently, there are no existing vaccines able to protect human hosts from these infections and thus, vector control strategies such as Wolbachia mass release program is regarded as a viable option. Considerable evidence demonstrates how the presence of Wolbachia interferes with arboviruses by decreasing cellular components vital for the pathogen and strengthening antiviral host responses. However, variation in the magnitude of Wolbachia’s viral inhibition that is neither due to strain nor density has been observed. Furthermore, the cellular mechanisms involved in the endosymbiont’s pathogen-blocking differs among hosts. This prompts the need to explore the cellular interactions between Ae. aegypti-arboviruses-Wolbachia and how these interactions overall affect the mosquito’s cell. Understanding what happens at the cellular and molecular level will provide evidence on the sustainability of Wolbachia vector control.

scholarly journals Workshop for priority-setting in Aedes aegypti control interventions in Latin America and the Caribbean: a policy dialogue

2019 ◽  
Vol 35 (4) ◽  
Author(s):  
Agustin Ciapponi ◽  
Ariel Bardach ◽  
Andrea Alcaraz ◽  
María Belizán ◽  
Daniel Jones ◽  
...  
Keyword(s):  
Latin America ◽  
Aedes Aegypti ◽  
Vector Control ◽  
Priority Setting ◽  
Mosquito Control ◽  
Control Strategies ◽  
Policy Dialogue ◽  
Regional Research ◽  
Deliberative Process ◽  
The Caribbean

This article presents the results of a dialogue between decision-makers and experts in Latin America and the Caribbean on priority-setting for interventions and studies on Aedes aegypti control. The article is part of a project that included a systematic review of mosquito control strategies and a qualitative study with key informants from the region. Using a collective deliberative process assisted by the results of the above-mentioned projects, a list of priorities was developed by consensus for the implementation of vector control strategies and the development of key regional research lines. It was agreed that the best strategy is integrated vector management, divided into: (a) chemical control; (b) biological control; (c) environmental management; (d) community participation; and (e) integrated surveillance. The workshop highlighted the crucial role of government leadership and inter-sector coordination between government agencies and civil society stakeholders. The proposed priorities for research lines were: Ae. aegypti vector competence and associated factors; community components of interventions; incorporation of technology into vector control and monitoring; most efficient modalities of integrated surveillance; entomological indicators with the best predictive capacity; and resistance to insecticides. The policy dialogue methodology allowed validating and enriching the results of other levels of research, besides establishing priorities for regional research and control strategies.

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

2021 ◽  
Vol 15 (2) ◽  
pp. e0008492 ◽  
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.

scholarly journals Phenotypic and haplotypic profiles of insecticide resistance in populations of Aedes aegypti larvae (Diptera: Culicidae) from central Lao PDR

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Takaki Shimono ◽  
Seiji Kanda ◽  
Pheophet Lamaningao ◽  
Yuki Murakami ◽  
Andrew Waleluma Darcy ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Pyrethroid Resistance ◽  
Control Strategies ◽  
Lao Pdr ◽  
Resistance Mechanisms ◽  
Cytochrome P450 Monooxygenases ◽  
Bacillus Thuringiensis Israelensis ◽  
Vector Management

Abstract Background Aedes aegypti, which is widely distributed in the Lao People’s Democratic Republic (PDR), is the primary vector of arboviral diseases. Chemical insecticides have been intensively used to eliminate mosquito-borne diseases, resulting in the development of insecticide resistance. However, little is known about the insecticide resistance of mosquito populations in Lao PDR and the mechanisms responsible for it, which have important implications for vector management programs. Here, we examined the phenotypic and haplotypic profiles of insecticide resistance in populations of Ae. aegypti larvae from central Lao PDR. Methods Ae. aegypti larvae were collected from four sites in Lao PDR, and their susceptibility to temephos, deltamethrin, permethrin, and Bacillus thuringiensis israelensis (Bti) was tested using larval bioassays. Synergistic tests were also conducted to evaluate the activity of insecticide-metabolizing enzymes in the larvae. Deltamethrin-resistant and Deltamethrin-susceptible larvae were then genotyped for knockdown resistance (kdr) mutations to determine the associations between each genotype and resistance. Results Ae. aegypti larvae from central Lao PDR were considered to be “resistant” (<98% mortality) to organophosphates and pyrethroids. The bio-insecticide Bti remains effective against such larvae. The resistance mechanisms of Ae. aegypti larvae were found to vary among populations, especially for pyrethroid resistance. Kdr mutations were significantly associated with deltamethrin resistance in Ae. aegypti from the Xaythany population. In contrast, synergist assays with piperonyl butoxide suggested that cytochrome P450 monooxygenases played an important role in the resistance seen in the Khounkham and Thakhek populations. Conclusion This study obtained information that will aid the design and implementation of insecticide-based vector management of Ae. aegypti in central Lao PDR. Ae. aegypti larvae from central Lao PDR were highly susceptible to Bti, while they were resistant to temephos at a diagnostic dose of 0.0286 mg/L. Given the limited number of insecticides that are approved for vector control, it is important to alternate between temephos and other larvicides, such as Bti and pyriproxyfen. The differences in pyrethroid resistance mechanisms seen among the Ae. aegypti populations highlight the need to tailor vector-control strategies to each region to increase the success of dengue control in Lao PDR.

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

Acta Tropica ◽  
2013 ◽  
Vol 128 (3) ◽  
pp. 598-605
Author(s):  
Kathleen R. Souza ◽  
Gilmar Ribeiro ◽  
Carlos Gustavo Silva dos Santos ◽  
Eliaci Couto de Lima ◽  
Paulo R.S. Melo ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Aedes Aegypti ◽  
Vector Control ◽  
Metropolitan Area ◽  
Control Measures

scholarly journals Spatial pattern evolution of Aedes aegypti breeding sites in an Argentinean city without a dengue vector control programme

2016 ◽  
Vol 11 (3) ◽  
Author(s):  
Manuel O. Espinosa ◽  
Francisco Polop ◽  
Camilo H. Rotela ◽  
Marcelo Abril ◽  
Carlos M. Scavuzzo
Keyword(s):  
Aedes Aegypti ◽  
Vector Control ◽  
Urban Areas ◽  
Control Strategies ◽  
Dengue Vector ◽  
Risk Area ◽  
Niche Model ◽  
Temporal Behaviour ◽  
Breeding Sites ◽  
Time Dynamics

The main objective of this study was to obtain and analyse the space-time dynamics of <em>Aedes aegypti</em> breeding sites in Clorinda City, Formosa Province, Argentina coupled with landscape analysis using the maximum entropy approach in order to generate a dengue vector niche model. In urban areas, without vector control activities, 12 entomologic (larval) samplings were performed during three years (October 2011 to October 2014). The entomologic surveillance area represented 16,511 houses. Predictive models for <em>Aedes</em> distribution were developed using vector breeding abundance data, density analysis, clustering and geoprocessing techniques coupled with Earth observation satellite data. The spatial analysis showed a vector spatial distribution pattern with clusters of high density in the central region of Clorinda with a well-defined high-risk area in the western part of the city. It also showed a differential temporal behaviour among different areas, which could have implications for risk models and control strategies at the urban scale. The niche model obtained for <em>Ae. aegypti</em>, based on only one year of field data, showed that 85.8% of the distribution of breeding sites is explained by the percentage of water supply (48.2%), urban distribution (33.2%), and the percentage of urban coverage (4.4%). The consequences for the development of control strategies are discussed with reference to the results obtained using distribution maps based on environmental variables.

scholarly journals Field Effectiveness of Drones to Identify Potential Aedes aegypti Breeding Sites in Household Environments from Tapachula, a Dengue-Endemic City in Southern Mexico

Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 663
Author(s):  
Kenia Mayela Valdez-Delgado ◽  
David A. Moo-Llanes ◽  
Rogelio Danis-Lozano ◽  
Luis Alberto Cisneros-Vázquez ◽  
Adriana E. Flores-Suarez ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Vector Control ◽  
Rural Areas ◽  
Aerial Images ◽  
Ground Field ◽  
Southern Mexico ◽  
Breeding Sites ◽  
Larval Habitats ◽  
Control Programs ◽  
Urban And Rural Areas

Aedes aegypti control programs require more sensitive tools in order to survey domestic and peridomestic larval habitats for dengue and other arbovirus prevention areas. As a consequence of the COVID-19 pandemic, field technicians have faced a new occupational hazard during their work activities in dengue surveillance and control. Safer strategies to monitor larval populations, in addition to minimum householder contact, are undoubtedly urgently needed. Drones can be part of the solution in urban and rural areas that are dengue-endemic. Throughout this study, the proportion of larvae breeding sites found in the roofs and backyards of houses were assessed using drone images. Concurrently, the traditional ground field technician’s surveillance was utilized to sample the same house groups. The results were analyzed in order to compare the effectiveness of both field surveillance approaches. Aerial images of 216 houses from El Vergel village in Tapachula, Chiapas, Mexico, at a height of 30 m, were obtained using a drone. Each household was sampled indoors and outdoors by vector control personnel targeting all the containers that potentially served as Aedes aegypti breeding sites. The main results were that the drone could find 1 container per 2.8 found by ground surveillance; however, containers that were inaccessible by technicians in roofs and backyards, such as plastic buckets and tubs, disposable plastic containers and flowerpots were more often detected by drones than traditional ground surveillance. This new technological approach would undoubtedly improve the surveillance of Aedes aegypti in household environments, and better vector control activities would therefore be achieved in dengue-endemic countries.

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