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1.
Bioorg Chem ; 150: 107591, 2024 Jun 24.
Article in English | MEDLINE | ID: mdl-38964147

ABSTRACT

Some heterocycles bearing a benzo[h]quinoline moiety were synthesized through treating a 3-((2-chlorobenzo[h]quinolin-3-yl)methylene)-5-(p-tolyl)furan-2(3H)-one with four nitrogen nucleophiles comprising ammonium acetate, benzylamine, dodecan-1-amine, and 1,2-diaminoethane. Also, thiation reactions of furanone and pyrrolinone derivatives were investigated. The insecticidal activity of these compounds against mosquito larvae (Culex pipiens L.) was evaluated. All tested compounds exhibited significant larvicidal activity, surpassing that of the conventional insecticide chlorpyrifos. In silico docking analysis revealed that these compounds may act as acetyl cholinesterase (AChE) inhibitors, potentially explaining their larvicidal effect. Additionally, interactions with other neuroreceptors, such as nicotinic acetylcholine receptor and sodium channel voltage-gated alpha subunit were also predicted. The results obtained from this study reflected the potential of benzo[h]quinoline derivatives as promising candidates for developing more effective and sustainable mosquito control strategies. The ADME (absorption, distribution, metabolism, and excretion) analyses displayed their desirable drug-likeness and oral bioavailability properties.

2.
Sci Rep ; 14(1): 15421, 2024 07 04.
Article in English | MEDLINE | ID: mdl-38965297

ABSTRACT

Aedes aegypti and Aedes albopictus are the main vectors of arboviruses such as Dengue, Chikungunya and Zika, causing a major impact on global economic and public health. The main way to prevent these diseases is vector control, which is carried out through physical and biological methods, in addition to environmental management. Although chemical insecticides are the most effective strategy, they present some problems such as vector resistance and ecotoxicity. Recent research highlights the potential of the imidazolium salt "1-methyl-3-octadecylimidazolium chloride" (C18MImCl) as an innovative and environmentally friendly solution against Ae. aegypti. Despite its promising larvicidal activity, the mode of action of C18MImCl in mosquito cells and tissues remains unknown. This study aimed to investigate its impacts on Ae. aegypti larvae and three cell lines of Ae. aegypti and Ae. albopictus, comparing the cellular effects with those on human cells. Cell viability assays and histopathological analyses of treated larvae were conducted. Results revealed the imidazolium salt's high selectivity (> 254) for mosquito cells over human cells. After salt ingestion, the mechanism of larval death involves toxic effects on midgut cells. This research marks the first description of an imidazolium salt's action on mosquito cells and midgut tissues, showcasing its potential for the development of a selective and sustainable strategy for vector control.


Subject(s)
Aedes , Imidazoles , Insecticides , Larva , Aedes/drug effects , Animals , Larva/drug effects , Imidazoles/toxicity , Imidazoles/pharmacology , Insecticides/toxicity , Insecticides/pharmacology , Humans , Mosquito Vectors/drug effects , Cell Line , Cell Survival/drug effects , Mosquito Control/methods
3.
Acta Trop ; 257: 107290, 2024 Jun 22.
Article in English | MEDLINE | ID: mdl-38909722

ABSTRACT

Mosquito borne diseases are impeding to human health due to their uncontrolled proliferation. Various commercial insecticides currently used become ineffective due to the resistance acquired by mosquitoes. It is necessary and a priority to combat mosquito population. Plant-based products are gaining interest over the past few decades due to their environment friendliness and their effectiveness in controlling mosquitoes along with their lack of toxicity. Essential oil nanoemulsions are found to be highly effective when compared to their bulk counterparts. Due to their nano size, they can effectively interact and yield 100 % mortality with the mosquito larvae and encounter with minimal concentrations. This is the main advantage of the nano-sized particles due to which they find application in various disciplines and have also received the attention of researchers globally. There are various components present in essential oils that have been analysed using GC-MS. These findings reflect the challenge to mosquitoes to gain resistance against each component and therefore it requires time. Commercially used repellants are synthesised using materials like DEET are not advisable for topical application on human skin and essential oil nanoemulsions could be an ideal non toxic candidate that can be used against mosquito adults and larvae. However, there are other synthesis, optimisation parameters, and toxicity towards non-target organisms that have to be taken into account when essential oil nanoemulsions are considered for commercial applications. Here we review the strategies used by the nanoemulsions against the mosquito population. Apart from the positive effects, their minor drawbacks also have to be scrutinised in the future.

4.
Microbiol Spectr ; 12(7): e0379223, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38809029

ABSTRACT

The entomopathogenic fungus Beauveria bassiana provides an eco-friendly substitute to chemical insecticides for mosquito control. Nevertheless, its widespread application has been hindered by its comparatively slow efficacy in eliminating mosquitoes. To augment the potency of B. bassiana against Aedes mosquitoes, a novel recombinant strain, Bb-Cyt1Aa, was developed by incorporating the Bacillus thuringiensis toxin gene Cyt1Aa into B. bassiana. The virulence of Bb-Cyt1Aa was evaluated against Aedes aegypti and Aedes albopictus using insect bioassays. Compared to the wild-type (WT) strain, the median lethal time (LT50) for A. aegypti larvae infected with Bb-Cyt1Aa decreased by 33.3% at a concentration of 1 × 108 conidia/mL and by 22.2% at 1 × 107 conidia/mL. The LT50 for A. aegypti adults infected with Bb-Cyt1Aa through conidia ingestion was reduced by 37.5% at 1 × 108 conidia/mL and by 33.3% at 1 × 107 conidia/mL. Likewise, the LT50 for A. aegypti adults infected with Bb-Cyt1Aa through cuticle contact decreased by 33.3% and 30.8% at the same concentrations, respectively. Furthermore, the Bb-Cyt1Aa strain also demonstrated increased toxicity against both larval and adult A. albopictus, when compared to the WT strain. In conclusion, our study demonstrated that the expression of B. thuringiensis toxin Cyt1Aa in B. bassiana enhanced its virulence against Aedes mosquitoes. This suggests that B. bassiana expressing Cyt1Aa has potential value for use in mosquito control. IMPORTANCE: Beauveria bassiana is a naturally occurring fungus that can be utilized as a bioinsecticide against mosquitoes. Cyt1Aa is a delta-endotoxin protein produced by Bacillus thuringiensis that exhibits specific and potent insecticidal activity against mosquitoes. In our study, the expression of this toxin Cyt1Aa in B. bassiana enhances the virulence of B. bassiana against Aedes aegypti and Aedes albopictus, thereby increasing their effectiveness in killing mosquitoes. This novel strain can be used alongside chemical insecticides to reduce dependence on harmful chemicals, thereby minimizing negative impacts on the environment and human health. Additionally, the potential resistance of B. bassiana against mosquitoes in the future could be overcome by acquiring novel combinations of exogenous toxin genes. The presence of B. bassiana that expresses Cyt1Aa is of significant importance in mosquito control as it enhances genetic diversity, creates novel virulent strains, and contributes to the development of safer and more sustainable methods of mosquito control.


Subject(s)
Aedes , Bacillus thuringiensis Toxins , Bacillus thuringiensis , Beauveria , Endotoxins , Hemolysin Proteins , Larva , Mosquito Control , Pest Control, Biological , Animals , Beauveria/genetics , Beauveria/pathogenicity , Beauveria/metabolism , Aedes/microbiology , Mosquito Control/methods , Bacillus thuringiensis Toxins/genetics , Hemolysin Proteins/genetics , Hemolysin Proteins/metabolism , Bacillus thuringiensis/genetics , Bacillus thuringiensis/metabolism , Endotoxins/genetics , Endotoxins/metabolism , Pest Control, Biological/methods , Larva/microbiology , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Virulence/genetics , Spores, Fungal/genetics , Insecticides/pharmacology , Insecticides/metabolism
5.
Ecohealth ; 21(1): 9-20, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38658454

ABSTRACT

Invasive mosquitoes are an emerging public health issue, as many species are competent vectors for pathogens. We assessed how multiple environmental and socio-economic factors affected the engagement of municipalities in Italy (n = 7679) in actions against Aedes albopictus, an invasive mosquito affecting human health and well-being, between 2000 and 2020. We collected information about mosquito control from official documents and municipal websites and modeled the role played by multiple environmental and socioeconomic factors characterizing each municipality through the random forest algorithm. Municipalities are more prone to manage A. albopictus if more urbanized, in lowlands and with long infestation periods. Moreover, these variables are more predictive of management in municipalities with a high median income and thus more economic resources. Only 25.5% of Italian municipalities approved regulations for managing A. albopictus, and very few of them were in Southern Italy, the most deprived area of the country. Our findings indicate that local economic conditions moderate the effect of other drivers of mosquito control and ultimately can lead to better management of A. albopictus. If the management of invasive mosquitoes, or other forms of global change, is subjected to local economic conditions, economic inequalities will jeopardize the success of large-scale policies, also raising issues of environmental and climate justice.


Subject(s)
Aedes , Mosquito Control , Mosquito Vectors , Animals , Italy , Mosquito Control/economics , Socioeconomic Factors , Humans , Introduced Species/economics , Cities
6.
Pest Manag Sci ; 80(8): 3912-3921, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38517127

ABSTRACT

BACKGROUNDS: In order to provide a long-lasting formulation for spinosad (SP) targeting larval stages of Aedes aegypti (Linnaeus) and others alike, a SP tablet was developed based on microspheres, using polylactic acid as inside coating material. The microspheres were encapsulated using polyethylene glycol and 1-hexadecanol to form a sustained-release SP tablet. Micromorphology, active ingredient loading, structure identification, photolysis resistance and biological activity were evaluated in this report. RESULTS: (i) The SP microspheres had an average particle size of 6.16 ± 2.28 µm, low adhesion and good dispersion as evaluated by scanning electron microscopy and morphology. (ii) The average active ingredient loading and encapsulation of SP microspheres were 32.80 ± 0.74% and 78.41 ± 2.22%, respectively. (iii) The chemical structure of encapsulated SP was confirmed by Fourier transform infrared and 1H-nuclear magnetic resonance. (iv) The photostability of the microspheres and the tablets were evaluated. The results showed that DT50 (time required to dissipate 50% of the mass originally present) of SP was 0.95 days in microspheres and 6.94 days in tablets. (v) The long-term insecticidal activity of SP tablets was investigated, and the tablet had a long-lasting activity against the mosquito larvae, showing 100% larval mortality for 63 days. CONCLUSIONS: The study provided a new long-lasting formulation of SP, which displayed good efficacy in the control of Ae. aegypti larvae. © 2024 Society of Chemical Industry.


Subject(s)
Aedes , Drug Combinations , Insecticides , Larva , Macrolides , Microspheres , Animals , Aedes/drug effects , Aedes/growth & development , Insecticides/pharmacology , Insecticides/chemistry , Larva/drug effects , Larva/growth & development , Macrolides/pharmacology , Macrolides/chemistry , Tablets , Delayed-Action Preparations , Mosquito Control/methods
7.
J Med Entomol ; 61(3): 719-725, 2024 May 13.
Article in English | MEDLINE | ID: mdl-38521610

ABSTRACT

The emergence of insecticide resistance in mosquitoes necessitates the exploration and validation of sustainable biological strategies for controlling mosquitoes in their natural habitats. We assessed the predatory effect of Utricularia aurea Lour (Lamiales: Lentibulariaceae), an aquatic carnivorous plant found in the Indian subcontinent, Japan, and Australia, on 4 instars of Anopheles stephensi Liston, Culex quinquefasciatus Say, and Aedes aegypti Linn (Diptera: Culicidae), in the laboratory and field settings. In the laboratory setting, predation of larvae by U. aurea was highest during the first hour when it predated 45%, 61%, and 58% of first instars of An. stephensi, Cx. quinquefasciatus, and, Ae. aegypti, respectively, and, within 12 h, U. aurea preyed upon ~95% of the first, second, and third instars of the 3 mosquito species, ~80% of the fourth instars of An. stephensi and Ae. aegypti, and ~60% of fourth instars of Cx. quinquefasciatus. The predatory effect of U. aurea varied with mosquito species and instar. Broadly, predation risk declined with the increase of the instar size. In the field setting, at the end of 16 days, U. aurea predated 76% and 71% of the immature An. stephensi and Ae. aegypti, respectively. Our findings suggest U. aurea can be utilized as a potential biocontrol agent for controlling mosquito larvae in natural habitats; however, the current claim warrants additional investigations in a variety of natural habitats.


Subject(s)
Aedes , Anopheles , Culex , Larva , Pest Control, Biological , Animals , Larva/growth & development , Larva/physiology , Culex/physiology , Aedes/physiology , Anopheles/physiology , Lamiales , Predatory Behavior , Mosquito Control
8.
J Am Mosq Control Assoc ; 40(1): 32-49, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38427588

ABSTRACT

The sterile insect technique (SIT) and the incompatible insect technique (IIT) are emerging and potentially revolutionary tools for controlling Aedes aegypti (L.), a prominent worldwide mosquito vector threat to humans that is notoriously difficult to reduce or eliminate in intervention areas using traditional integrated vector management (IVM) approaches. Here we provide an overview of the discovery, development, and application of SIT and IIT to Ae. aegypti control, and innovations and advances in technology, including transgenics, that could elevate these techniques to a worldwide sustainable solution to Ae. aegypti when combined with other IVM practices.


Subject(s)
Aedes , Wolbachia , Animals , Humans , Mosquito Control/methods , Mosquito Vectors , Insecta
9.
J Am Mosq Control Assoc ; 40(1): 50-70, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38353588

ABSTRACT

Strategies to advance action threshold development can benefit both civilian and military vector control operations. The Anastasia Mosquito Control District (AMCD) has curated an extensive record database of surveillance programs and operational control activities in St. Johns County, Florida, since 2004. A thorough exploratory data analysis was performed on historical mosquito surveillance and county-wide climate data to identify climate predictors that could be used in constructing proactive threshold models for initiating control of Aedes, Culex, and Anopheles vector mosquitoes. Species counts pulled from Centers for Disease Control and Prevention (CDC) light trap (2004-2019) and BG trap (2014-2019) collection records and climate parameters of temperature (minimum, maximum, average), rainfall, and relative humidity were used in two iterations of generalized linear models. Climate readings were incorporated into models 1) in the form of continuous measurements, or 2) for categorization into number of "hot," "wet," or "humid" days by exceedance of selected biological index threshold values. Models were validated with tests of residual error, comparison of model effects, and predictive capability on testing data from the two recent surveillance seasons 2020 and 2021. Two iterations of negative binomial regression models were constructed for 6 species groups: container Aedes (Ae. aegypti, Ae. albopictus), standing water Culex (Cx. nigripalpus, Cx. quinquefasciatus), floodwater Aedes (Ae. atlanticus, Ae. infirmatus), salt-marsh Aedes (Ae. taeniorhyncus, Ae. sollicitans), swamp water Anopheles (An. crucians), and a combined Total Mosquitoes group. Final significant climate predictors varied substantially between species groups. Validation of models with testing data displayed limited predictive abilities of both model iterations. The most significant climate predictors for floodwater Aedes, the dominant and operationally influential species group in the county, were either total precipitation or frequency of precipitation events (number of "wet" days) at two to four weeks before trap collection week. Challenges hindering the construction of threshold models were discussed. Insights gained from these models provide initial feedback for streamlining the AMCD mosquito control program and analytical recommendations for future modelling efforts of interested mosquito control programs, in addition to generalized guidance for deployed armed forces personnel with needs of mosquito control but lacking active surveillance programs.


Subject(s)
Aedes , Anopheles , Culex , Animals , Mosquito Vectors , Mosquito Control , Water
10.
Pest Manag Sci ; 80(7): 3140-3148, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38345320

ABSTRACT

BACKGROUND: Ultra-low volume (ULV) space sprays aerosolize insecticide formulated products (FP) to contact flying mosquitoes, while barrier sprays expose mosquitoes to FP residue on vegetation and other surfaces. Centers for Disease Control and Prevention bottle bioassays used to assess insecticide resistance are based on residual active ingredient (AI) exposure and do not directly relate to FP efficacy. The current pilot study developed a novel compact wind tunnel for mosquito exposure to FP. Caged Aedes albopictus and Culex pipiens/quinquefasciatus were exposed to undiluted Biomist®3 + 15 FP (permethrin AI) or air (control) within the wind tunnel, transferred to new cages, and held in a 28 °C incubator. Separate mosquitoes were exposed to residual permethrin AI (8 µg mL-1) in bottle bioassays. Mortality was monitored 15, 30, 60, and 120 min post-exposure. RESULTS: Chi-square tests (P < 0.05) showed significantly higher mortality in Aedes compared to Culex populations for most time points in both bioassay and wind tunnel exposure groups. As expected, mosquitoes exposed to Biomist®3 + 15 showed higher mortality rates than bottle bioassay exposure to permethrin. Two Culex colonies resistant to permethrin in bottle bioassays were susceptible to Biomist®3 + 15 in the wind tunnel. CONCLUSION: The novel compact wind tunnel developed here may be an alternative to field trials for testing FP efficacy, avoiding factors such as weather, logistical planning, and extended personnel hours. The wind tunnel could allow programs to conveniently test efficacy of multiple FP. Comparisons of different insecticide exposure methods provide practical information to inform operational decisions. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Subject(s)
Aedes , Culex , Insecticides , Mosquito Control , Permethrin , Animals , Insecticides/pharmacology , Permethrin/pharmacology , Culex/drug effects , Aedes/drug effects , Mosquito Control/methods , Pilot Projects , Female , Wind , Insecticide Resistance
11.
Malar J ; 23(1): 8, 2024 Jan 04.
Article in English | MEDLINE | ID: mdl-38178145

ABSTRACT

Africa and the United States are both large, heterogeneous geographies with a diverse range of ecologies, climates and mosquito species diversity which contribute to disease transmission and nuisance biting. In the United States, mosquito control is nationally, and regionally coordinated and in so much as the Centers for Disease Control (CDC) provides guidance, the Environmental Protection Agency (EPA) provides pesticide registration, and the states provide legal authority and oversight, the implementation is usually decentralized to the state, county, or city level. Mosquito control operations are organized, in most instances, into fully independent mosquito abatement districts, public works departments, local health departments. In some cases, municipalities engage independent private contractors to undertake mosquito control within their jurisdictions. In sub-Saharan Africa (SSA), where most vector-borne disease endemic countries lie, mosquito control is organized centrally at the national level. In this model, the disease control programmes (national malaria control programmes or national malaria elimination programmes (NMCP/NMEP)) are embedded within the central governments' ministries of health (MoHs) and drive vector control policy development and implementation. Because of the high disease burden and limited resources, the primary endpoint of mosquito control in these settings is reduction of mosquito borne diseases, primarily, malaria. In the United States, however, the endpoint is mosquito control, therefore, significant (or even greater) emphasis is laid on nuisance mosquitoes as much as disease vectors. The authors detail experiences and learnings gathered by the delegation of African vector control professionals that participated in a formal exchange programme initiated by the Pan-African Mosquito Control Association (PAMCA), the University of Notre Dame, and members of the American Mosquito Control Association (AMCA), in the United States between the year 2021 and 2022. The authors highlight the key components of mosquito control operations in the United States and compare them to mosquito control programmes in SSA countries endemic for vector-borne diseases, deriving important lessons that could be useful for vector control in SSA.


Subject(s)
Malaria , Mosquito Control , Animals , United States , Malaria/epidemiology , Africa South of the Sahara , Ecology , Disease Vectors , Mosquito Vectors
12.
Parasit Vectors ; 17(1): 37, 2024 Jan 29.
Article in English | MEDLINE | ID: mdl-38287368

ABSTRACT

BACKGROUND: There is an urgent need for cities to become more climate resilient; one of the key strategies is to include more green spaces in the urban environment. Currently, there is a worry that increasing green spaces might increase mosquito nuisance. As such, this study explores a comprehensive understanding of how mosquitoes utilise contrasting grey and green habitats at different life stages and which environmental factors could drive these distributions. METHODS: We used a setup of six paired locations, park (green) vs. residential (grey) areas in a single model city (Leiden, The Netherlands), where we sampled the abundances of different mosquito life stages (eggs, larvae, adults) and the local microclimatic conditions. In this study, we focused on Culex pipiens s.l., which is the most common and abundant mosquito species in The Netherlands. RESULTS: Our results show that while Cx. pipiens ovipositioning rates (number of egg rafts) and larval life stages were far more abundant in residential areas, adults were more abundant in parks. These results coincide with differences in the number of suitable larval habitats (higher in residential areas) and differences in microclimatic conditions (more amenable in parks). CONCLUSIONS: These findings suggest that Cx. pipiens dispersal may be considerably more important than previously thought, where adult Cx. pipiens seek out the most suitable habitat for survival and breeding success. Our findings can inform more targeted and efficient strategies to mitigate and reduce mosquito nuisance while urban green spaces are increased, which make cities more climate resilient.


Subject(s)
Culex , Ovum , Animals , Netherlands , Ecosystem , Cities , Larva
13.
J Med Entomol ; 61(1): 121-131, 2024 01 12.
Article in English | MEDLINE | ID: mdl-37742046

ABSTRACT

Mortality imposed on a population can interact with negatively density-dependent mortality to produce overcompensation, wherein added mortality results in more survivors. Experimental mortality can cause overcompensation in mosquito larvae, which would be counterproductive if it resulted from mosquito control in nature. We tested for different demographic responses to mortality among 3 container Aedes species when impacted by density dependence. We imposed 48.2% mortality on cohorts of larvae 2, 6, or 8 days after hatching and compared adult production, development times, and female size to those variables for controls without mortality. Mortality significantly increased adult production compared to controls, but the 3 species varied in the details of that response. Aedes albopictus (Skuse) produced more adults with mortality on day 2 primarily because of greater production of males. Aedes triseriatus (Say) yielded more adults with mortality on day 2 primarily because of greater production of females. Aedes aegypti (L.) adult production was not significantly affected by mortality, but development times for both sexes were significantly shorter with mortality on day 8. There were no effects of mortality on female wing length. None of our mortality treatments yielded significant reductions of adults for any species. These species responses to mortality are not the same, despite their similar ecologies and life histories. Thus, we cannot assume that killing almost half the larvae present in a dense population will reduce adult production, nor can we assume that different Aedes species will respond to mortality in the same way.


Subject(s)
Aedes , Male , Animals , Female , Larva , Aedes/physiology , Ecology , Demography
14.
Environ Toxicol Chem ; 43(2): 267-278, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37921583

ABSTRACT

Nontarget effects from mosquito control operations are possible in habitats adjacent to areas targeted by ultra-low-volume (ULV) sprays of permethrin for adult mosquito control. We assessed the risks of permethrin exposure to butterflies, particularly the imperiled Klot's skipper, when exposed to ground-based ULV sprays. Samples of larval host plant leaves (sawgrass) were collected in June (in mosquito season) and January (outside mosquito season) of 2015 from sawgrass marsh habitats of the National Key Deer Wildlife Refuge (Big Pine Key, FL, USA) and analyzed for permethrin. Permethrin detection was higher in June (detected on 70% of samples) than in January (30%), and concentrations were significantly higher in June (geomean = 2.1 ng/g, median = 2.4) relative to January (0.4 ng/g, median = 0.2). Dietary risk for 4th to 5th-instar larvae was low based on the measured residues. The AGricultural DISPersal model (Ver. 8.26) was used to estimate permethrin residues on sawgrass following ULV sprays (deposited residues) to estimate immediate postspray risk. Estimated deposited residues (33-543 ng/g) were much higher than measured residues, which leads to a higher risk likelihood for butterfly larvae immediately after ULV sprays. The difference between estimated and measured residues, and between the two risk estimations, reflects uncertainty in risk estimates based on the measured residues. Research on modeling deposited pesticide residues following ground-based ULV spray is limited. More research on estimating deposited pesticide residues from truck-mounted ULV sprayers could help reduce uncertainty in the risk predictions for nontarget insects like butterflies. Environ Toxicol Chem 2024;43:267-278. Published 2023. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.


Subject(s)
Butterflies , Deer , Insecticides , Pesticide Residues , Animals , Permethrin , Wetlands , Larva , Mosquito Control
15.
Mol Biol Evol ; 41(1)2024 Jan 03.
Article in English | MEDLINE | ID: mdl-38128148

ABSTRACT

The mosquito family Culicidae is divided into 2 subfamilies named the Culicinae and Anophelinae. Nix, the dominant male-determining factor, has only been found in the culicines Aedes aegypti and Aedes albopictus, 2 important arboviral vectors that belong to the subgenus Stegomyia. Here we performed sex-specific whole-genome sequencing and RNAseq of divergent mosquito species and explored additional male-inclusive datasets to investigate the distribution of Nix. Except for the Culex genus, Nix homologs were found in all species surveyed from the Culicinae subfamily, including 12 additional species from 3 highly divergent tribes comprising 4 genera, suggesting Nix originated at least 133 to 165 million years ago (MYA). Heterologous expression of 1 of 3 divergent Nix open reading frames (ORFs) in Ae. aegypti resulted in partial masculinization of genetic females as evidenced by morphology and doublesex splicing. Phylogenetic analysis suggests Nix is related to femaleless (fle), a recently described intermediate sex-determining factor found exclusively in anopheline mosquitoes. Nix from all species has a conserved structure, including 3 RNA-recognition motifs (RRMs), as does fle. However, Nix has evolved at a much faster rate than fle. The RRM3 of both Nix and fle are distantly related to the single RRM of a widely distributed and conserved splicing factor transformer-2 (tra2). The RRM3-based phylogenetic analysis suggests this domain in Nix and fle may have evolved from tra2 or a tra2-related gene in a common ancestor of mosquitoes. Our results provide insights into the evolution of sex determination in mosquitoes and will inform broad applications of mosquito-control strategies based on manipulating sex ratios toward nonbiting males.


Subject(s)
Aedes , Mosquito Vectors , Animals , Female , Male , Phylogeny , Mosquito Vectors/genetics , Aedes/genetics , Aedes/metabolism , RNA Splicing
16.
Insects ; 14(12)2023 Dec 15.
Article in English | MEDLINE | ID: mdl-38132622

ABSTRACT

Eco-friendly new mosquito control innovations are critical for the ongoing success of global mosquito control programs. In this study, Sh.463_56.10R, a robust RNA interference (RNAi) yeast insecticide strain that is suitable for scaled fermentation, was evaluated under semi-field conditions. Inactivated and dried Sh.463_56.10R yeast induced significant mortality of field strain Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus larvae in semi-field larvicide trials conducted outdoors in St. Augustine, Trinidad, where 100% of the larvae were dead within 24 h. The yeast was also stably suspended in commercial bait and deployed as an active ingredient in miniature attractive targeted sugar bait (ATSB) station sachets. The yeast ATSB induced high levels of Aedes and Culex mosquito morbidity in semi-field trials conducted in Trinidad, West Indies, as well as in Bangkok, Thailand, in which the consumption of the yeast resulted in adult female mosquito death within 48 h, faster than what was observed in laboratory trials. These findings support the pursuit of large-scale field trials to further evaluate the Sh.463_56.10R insecticide, a member of a promising new class of species-specific RNAi insecticides that could help combat insecticide resistance and support effective mosquito control programs worldwide.

17.
J Am Mosq Control Assoc ; 39(4): 243-250, 2023 Dec 01.
Article in English | MEDLINE | ID: mdl-38108429

ABSTRACT

Mosquitoes are a known public nuisance and can vector various diseases. Historically, New Orleans, LA, has long been acquainted with the burden of mosquito-borne diseases, such as malaria and yellow fever in the 20th century and West Nile virus in the 21st century. Government mosquito control awareness campaigns have been around for decades as has the use of organophosphate and pyrethroid insecticides by mosquito abatement districts. However, few data are available on public perception of mosquito control and public usage of insecticides to kill mosquitoes in New Orleans. We conducted a survey from August 2020 to July 2021 to evaluate New Orleans residents' 1) general knowledge regarding mosquito control and 2) what measures and products they use to control mosquitoes. The aim of this survey was to determine how residents contribute to backyard mosquito control by do-it-yourself or professional applications of insecticides. The survey was disseminated both online and via mail. Of the 396 survey participants, nearly all (99.48%) agreed that mosquito control is important in New Orleans because it prevents mosquito bites (30.85%), prevents mosquito borne-diseases (38.51%), and prevents nuisance mosquitoes (29.17%). More than one-third (35%) of survey participants indicated that they empty containers to reduce adult mosquitoes on their own property. More than two-thirds of the participants (69.95%) would not hire a pest management professional to spray their yard for adult mosquitoes, and only 20% of survey participants do apply a pesticide to kill adult mosquitoes on their own property. None of our findings were associated with the level of education, gender, or age of participants. This study suggests that the City of New Orleans Mosquito, Termite and Rodent Control Board educational and outreach campaigns may be an effective tool in spreading mosquito control awareness and contribute to residents' knowledge of mosquito control. The data we collected indicate that residents understand what mosquito control is and why it is important in New Orleans.


Subject(s)
Insecticides , Mosquito-Borne Diseases , Adult , Animals , Humans , New Orleans , Mosquito Control , Knowledge
18.
Parasit Vectors ; 16(1): 417, 2023 Nov 15.
Article in English | MEDLINE | ID: mdl-37964334

ABSTRACT

BACKGROUND: A three-dimensional window screen (3D-Screen) has been developed to create a window double-screen trap (3D-WDST), effectively capturing and preventing the escape of mosquitoes. A 2015 laboratory study demonstrated the 3D-Screen's efficacy, capturing 92% of mosquitoes in a double-screen setup during wind tunnel assays. To further evaluate its effectiveness, phase II experimental hut trials were conducted in Muheza, Tanzania. METHODS: Three experimental hut trials were carried out between 2016 and 2017. Trial I tested two versions of the 3D-WDST in huts with open or closed eaves, with one version using a single 3D-Screen and the other using two 3D-Screens. Trial II examined the 3D-WDST with two 3D-Screens in huts with or without baffles, while Trial III compared handmade and machine-made 3D structures. Mosquito capturing efficacy of the 3D-WDST was measured by comparing the number of mosquitoes collected in the test hut to a control hut with standard exit traps. RESULTS: Trial I showed that the 3D-WDST with two 3D-Screens used in huts with open eaves achieved the highest mosquito-capturing efficacy. This treatment captured 33.11% (CI 7.40-58.81) of female anophelines relative to the total collected in this hut (3D-WDST and room collections) and 27.27% (CI 4.23-50.31) of female anophelines relative to the total collected in the control hut (exit traps, room, and verandahs collections). In Trial II, the two 3D-Screens version of the 3D-WDST captured 70.32% (CI 56.87-83.77) and 51.07% (CI 21.72-80.41) of female anophelines in huts with and without baffles, respectively. Compared to the control hut, the capturing efficacy for female anophelines was 138.6% (37.23-239.9) and 42.41% (14.77-70.05) for huts with and without baffles, respectively. Trial III demonstrated similar performance between hand- and machine-made 3D structures. CONCLUSIONS: The 3D-WDST proved effective in capturing malaria vectors under semi-field experimental hut conditions. Using 3D-Screens on both sides of the window openings was more effective than using a single-sided 3D-Screen. Additionally, both hand- and machine-made 3D structures exhibited equally effective performance, supporting the production of durable cones on an industrial scale for future large-scale studies evaluating the 3D-WDST at the community level.


Subject(s)
Anopheles , Insecticides , Malaria , Female , Animals , Mosquito Control/methods , Mosquito Vectors , Tanzania , Malaria/prevention & control
19.
J Am Mosq Control Assoc ; 36(4)2023 Oct 23.
Article in English | MEDLINE | ID: mdl-37866823

ABSTRACT

Mosquitoes are a known public nuisance and can vector various diseases. Historically, New Orleans, LA, has long been acquainted with the burden of mosquito-borne diseases, such as malaria and yellow fever in the 20th century and West Nile virus in the 21st century. Government mosquito control awareness campaigns have been around for decades as has the use of organophosphate and pyrethroid insecticides by mosquito abatement districts. However, few data are available on public perception of mosquito control and public usage of insecticides to kill mosquitoes in New Orleans. We conducted a survey from August 2020 to July 2021 to evaluate New Orleans residents' 1) general knowledge regarding mosquito control and 2) what measures and products they use to control mosquitoes. The aim of this survey was to determine how residents contribute to backyard mosquito control by do-it-yourself or professional applications of insecticides. The survey was disseminated both online and via mail. Of the 396 survey participants, nearly all (99.48%) agreed that mosquito control is important in New Orleans because it prevents mosquito bites (30.85%), prevents mosquito borne-diseases (38.51%), and prevents nuisance mosquitoes (29.17%). More than one-third (35%) of survey participants indicated that they empty containers to reduce adult mosquitoes on their own property. More than two-thirds of the participants (69.95%) would not hire a pest management professional to spray their yard for adult mosquitoes, and only 20% of survey participants do apply a pesticide to kill adult mosquitoes on their own property. None of our findings were associated with the level of education, gender, or age of participants. This study suggests that the City of New Orleans Mosquito, Termite and Rodent Control Board educational and outreach campaigns may be an effective tool in spreading mosquito control awareness and contribute to residents' knowledge of mosquito control. The data we collected indicate that residents understand what mosquito control is and why it is important in New Orleans.


Subject(s)
Insecticides , Pyrethrins , Adult , Animals , Humans , Mosquito Control , New Orleans , Surveys and Questionnaires
20.
PeerJ ; 11: e16259, 2023.
Article in English | MEDLINE | ID: mdl-37868071

ABSTRACT

The entomopathogenic fungus Culicinomyces clavisporus is known to infect and kill mosquito larvae and therefore has been seen as a potential biological control agent against disease vector mosquitoes. Whereas most fungal entomopathogens infect hosts by penetrating the external cuticle, C. clavisporus initiates infection through ingestion (per os). This unique infection strategy suggests that the C. clavisporus genome may be mined for novel pathogenicity factors with potential for vector control. To this end, an Isoseq-based transcriptome analysis was initiated, and resulted in a total of 3,512,145 sequences, with an average length of 1,732 bp. Transcripts assembly and annotation suggested that the C. clavisporus transcriptome lacked the cuticle-degrading proteins that have been associated with other entomopathogenic fungi, supporting the per os pathogenicity process. Furthermore, mining of the sequence data unexpectedly revealed C. clavisporus transcripts homologous to the Hirsutellin toxin. Comparative sequence analyses indicated that the C. clavisporus Hirsutellin predicted protein has retained the canonical molecular features that have been associated with the ribotoxic and insecticidal properties of the original toxin isolated from Hirsutella thompsonii. The identification of an Hirsutellin ortholog in C. clavisporus was supported by phylogenetic analyses demonstrating that Culicinomyces and Hirsutella were closely related genera in the Ophiocordycipitaceae family. Validation of the mosquitocidal activity of this novel C. clavisporus protein has yet to be performed but may help position Hirsutellin orthologs as prime candidates for the development of alternative biocontrol approaches complementing the current toolbox of vector mosquito management strategies.


Subject(s)
Culicidae , Insecticides , Toxins, Biological , Animals , Insecticides/pharmacology , Transcriptome , Phylogeny , Mosquito Vectors
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