Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.957
Filtrar
1.
Ann Ist Super Sanita ; 58(3): 162-165, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36128963

RESUMO

INTRODUCTION: Aedes japonicus japonicus and Aedes koreicus are two invasive mosquitoes recently reported in various parts of Europe, including areas very close to Piedmont where, since 2012, specific tools have been implemented to allow the early detection of invasive mosquitoes, through the surveillance of the main points of entry. RESULTS: Thanks to the regional surveillance system, Ae. j. japonicus was intercepted in Piedmont for the first time in 2019, in the northernmost part of the region and now it is reported in six provinces. Ae. koreicus was intercepted for the first time in 2012 in three provinces. DISCUSSION AND CONCLUSION: The spread of these two invasive mosquitoes in Europe is still ongoing. Where Aedes albopictus is abundant, probably their presence goes undetected, therefore, it is crucial to begin surveillance early in the season. Due to their competence for several arboviruses and tolerance to the cold temperatures Ae. j. japonicus and Ae. koreicus represent a further concern for Public Health. A longer seasonal period for surveillance and response to mosquito-borne diseases, as well as a shift up of these activities to previously uncovered altitudes are indeed needed.


Assuntos
Aedes , Aedes/fisiologia , Animais , Europa (Continente) , Humanos , Espécies Introduzidas , Itália , Estações do Ano
2.
J Med Entomol ; 59(5): 1732-1740, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-35938709

RESUMO

Aedes aegypti mosquitoes are capable of vectoring a wide range of diseases including dengue, yellow fever, and Zika viruses, with approximately half of the worlds' population at risk from such diseases. Development of combined predator-parasite treatments for the control of larvae consistently demonstrates increased efficacy over single-agent treatments, however, the mechanism behind the interaction remains unknown. Treatments using the natural predator Toxorhynchites brevipalpis and the entomopathogenic fungus Metarhizium brunneum were applied in the laboratory against Ae. aegypti larvae as both individual and combined treatments to determine the levels of interaction between control strategies. Parallel experiments involved the removal of larvae from test arenas at set intervals during the course of the trial to record whole body caspase and phenoloxidase activities. This was measured via luminometric assay to measure larval stress factors underlying the interactions. Combined Metarhizium and Toxorhynchites treatments were seen to drastically reduce lethal times as compared to individual treatments. This was accompanied by increased phenoloxidase and caspase activities in combination treatments after 18 h (p < 0.001). The sharp increases in caspase and phenoloxidase activities suggest that combined treatments act to increase stress factor responses in the larvae that result in rapid mortality above that of either control agent individually. This work concludes that the underlying mechanism for increased lethality in combined parasite-predator treatments may be related to additive stress factors induced within the target host larvae.


Assuntos
Aedes , Culicidae , Hypocreales , Metarhizium , Infecção por Zika virus , Zika virus , Aedes/fisiologia , Animais , Caspases , Larva/fisiologia , Metarhizium/fisiologia , Monofenol Mono-Oxigenase , Controle de Mosquitos
3.
ACS Appl Mater Interfaces ; 14(33): 38320-38327, 2022 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-35960251

RESUMO

Mosquito-borne diseases such as dengue, chikungunya, and malaria have long been a health and economic burden in our society. Such illnesses develop after the pathogen, here arboviruses, are transmitted to humans by female mosquitoes during blood meals. In the case of dengue and chikungunya, such pathogens are transmitted to humans by infected Aedes aegypti females. Prior to feeding the insects rest on vertical surfaces. In this work, a surface roughness threshold was observed for live Aedes aegypti colonies, and below a root-mean-squared roughness of Sq < 0.124 µm the mosquitoes were physically incapable of gripping vertical substrates. This roughness threshold was unaffected by surface wettability or relative humidity. The importance of topographical feature height was understood using a claw-hooking model considering friction. Local defects above this threshold allowed claw hooking to take place, emphasizing the importance of surface uniformity. An antimosquito coating was developed that reduced surface roughness below this threshold when it was applied to realistic surfaces such as wood, brick, wall laminates, and tile. Lowering the surface roughness below the threshold reduced the number of mosquitoes capable of landing on the surfaces by 100%: i.e., no mosquitoes were able to adhere to the treated surfaces. The ability to completely inhibit Aedes aegypti females from landing on surfaces represents a new vector-borne disease control strategy that does not suffer from the nontarget toxicity, resistance, or ecosystem disruption associated with conventional chemical control strategies.


Assuntos
Aedes , Febre de Chikungunya , Vírus da Dengue , Dengue , Aedes/fisiologia , Animais , Vírus da Dengue/fisiologia , Ecossistema , Feminino , Humanos , Mosquitos Vetores/fisiologia
4.
Front Public Health ; 10: 959312, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35991044

RESUMO

Background: In metropolitan Tokyo in 2014, Japan experienced its first domestic dengue outbreak since 1945. The objective of the present study was to quantitatively assess the future risk of dengue in Japan using climate change scenarios in a high-resolution geospatial environment by building on a solid theory as a baseline in consideration of future adaptation strategies. Methods: Using climate change scenarios of the Model for Interdisciplinary Research on Climate version 6 (MIROC6), representative concentration pathway (RCP) 2.6, 4.5, and 8.5, we computed the daily average temperature and embedded this in the effective reproduction number of dengue, R(T), to calculate the extinction probability and interepidemic period across Japan. Results: In June and October, the R(T) with daily average temperature T, was <1 as in 2022; however, an elevation in temperature increased the number of days with R(T) >1 during these months under RCP8.5. The time period with a risk of dengue transmission gradually extended to late spring (April-May) and autumn (October-November). Under the RCP8.5 scenario in 2100, the possibility of no dengue-free months was revealed in part of southernmost Okinawa Prefecture, and the epidemic risk extended to the entire part of northernmost Hokkaido Prefecture. Conclusion: Each locality in Japan must formulate action plans in response to the presented scenarios. Our geographic analysis can help local governments to develop adaptation policies that include mosquito breeding site elimination, distribution of adulticides and larvicides, and elevated situation awareness to prevent transmission via bites from Aedes vectors.


Assuntos
Aedes , Mudança Climática , Aedes/fisiologia , Animais , Surtos de Doenças , Japão/epidemiologia , Mosquitos Vetores
5.
PLoS One ; 17(7): e0271248, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35802606

RESUMO

Malpighian tubules, the renal organs of mosquitoes, facilitate the rapid dehydration of blood meals through aquaporin-mediated osmosis. We performed phosphoproteomics analysis of three Malpighian tubule protein-libraries (1000 tubules/sample) from unfed female mosquitoes as well as one and 24 hours after a blood meal. We identified 4663 putative phosphorylation sites in 1955 different proteins. Our exploratory dataset reveals blood meal-induced changes in phosphorylation patterns in many subunits of V-ATPase, proteins of the target of rapamycin signaling pathway, vesicle-mediated protein transport proteins, proteins involved in monocarboxylate transport, and aquaporins. Our phosphoproteomics data suggest the involvement of a variety of new pathways including nutrient-signaling, membrane protein shuttling, and paracellular water flow in the regulation of urine excretion. Our results support a model in which aquaporin channels translocate from intracellular vesicles to the cell membrane of stellate cells and the brush border membrane of principal cells upon blood feeding.


Assuntos
Aedes , Aquaporinas , Aedes/fisiologia , Animais , Aquaporinas/metabolismo , Transporte Biológico , Feminino , Túbulos de Malpighi/metabolismo , Refeições , Proteínas/metabolismo
6.
Parasit Vectors ; 15(1): 254, 2022 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-35818063

RESUMO

BACKGROUND: The development of resistance against insecticides in Aedes aegypti can lead to operational failures in control programs. Knowledge of the spatial and temporal trends of this resistance is needed to drive effective monitoring campaigns, which in turn provide data on which vector control decision-making should be based. METHODS: Third-stage larvae (L3) from the F1 and F2 generations of 39 Peruvian field populations of Ae. aegypti mosquitoes from established laboratory colonies were evaluated for resistance against the organophosphate insecticide temephos. The 39 populations were originally established from eggs collected in the field with ovitraps in eight departments of Peru during 2018 and 2019. Dose-response bioassays, at 11 concentrations of the insecticide, were performed following WHO recommendations. RESULTS: Of the 39 field populations of Ae. aegypti tested for resistance to temephos , 11 showed high levels of resistance (resistance ratio [RR] > 10), 16 showed moderate levels of resistance (defined as RR values between 5 and 10) and only 12 were susceptible (RR < 5). The results segregated the study populations into two geographic groups. Most of the populations in the first geographic group, the coastal region, were resistant to temephos, with three populations (AG, CR and LO) showing RR values > 20 (AG 21.5, CR 23.1, LO 39.4). The populations in the second geographic group, the Amazon jungle and the high jungle, showed moderate levels of resistance, with values ranging between 5.1 (JN) and 7.1 (PU). The exception in this geographic group was the population from PM, which showed a RR value of 28.8 to this insecticide. CONCLUSIONS: The results of this study demonstrate that Ae. aegypti populations in Peru present different resistance intensities to temephos, 3 years after temephos use was discontinued. Resistance to this larvicide should continue to be monitored because it is possible that resistance to temephos could decrease in the absence of routine selection pressures.


Assuntos
Aedes , Inseticidas , Aedes/fisiologia , Animais , Resistência a Inseticidas , Inseticidas/farmacologia , Larva , Mosquitos Vetores , Peru , Temefós/farmacologia
7.
Photodiagnosis Photodyn Ther ; 39: 103030, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35872352

RESUMO

More than half of the global population lives in areas where the Aedes aegypti mosquito is present. Efforts have been made to deal with the population of this mosquito in the larval and adult stages to prevent outbreaks of diseases (Dengue, Zika, Chikungunya, and Yellow Fever). In this scenario, photodynamic inactivation may be an effective alternative method to control this vector population. To evaluate the efficacy of the riboflavin - B2 vitamin - as photosensitizer (PS) in the photodynamic inactivation of Ae. aegypti larvae, different concentrations (0; 0.005; 0.010; 0.025; 0.050; 0.075 and 0.100 mg mL-1) were evaluated under white light from RGB LEDs at a light dose of 495.2  J cm-2. The results reveal that riboflavin can be successfully applied as a PS agent to photoinactivate Ae. aegypti larvae, showing its potential to deal with the larvae population.


Assuntos
Aedes , Fotoquimioterapia , Infecção por Zika virus , Zika virus , Aedes/fisiologia , Animais , Larva , Mosquitos Vetores , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/farmacologia , Riboflavina/farmacologia
8.
J Med Entomol ; 59(5): 1687-1693, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-35794805

RESUMO

Entomopathogenic fungi allow chemical-free and environmentally safe vector management. Beauveria bassiana (Balsamo-Crivelli) Vuillemin is a promising biological control agent and an important component of integrated vector management. We investigated the mortality of Aedes albopictus (Skuse) larvae exposed to five concentrations of B. bassiana using Mycotrol ESO and adult oviposition behavior to analyze the egg-laying preferences of wild Ae. albopictus in response to different fungal concentrations. We examined the mortality of mid-instars exposed to B. bassiana concentrations of 1 × 104, 1 × 105, 1 × 106, 1 × 107, and 1 × 108 conidia/ml every 24 h for 12 d. In the oviposition behavior study, the fungus was applied to wooden paddles at 1 × 105, 1 × 107, and 1 × 109 conidia/ml, and the paddles were individually placed into quad-ovitraps. Both experiments contained control groups without B. bassiana. Kaplan-Meier survival analysis revealed that larval mortality was concentration dependent. The median lethal concentration was 2.43 × 105 conidia/ml on d 12. The median lethal time was 3.68 d at 1 × 106 conidia/ml. Oviposition monitoring revealed no significant difference in egg count between the control and treatment paddles. We observed an inverse relationship between the concentration of B. bassiana and the percentage of paddles with eggs. We concluded that concentrations above 1 × 106 conidia/ml are larvicidal, and Ae. albopictus laid similar numbers of eggs on fungus-impregnated and control wooden substrates; however, they were more likely to oviposit on substrates without B. bassiana. With these findings, we suggest that B. bassiana-infused ovitraps can be used for mosquito population monitoring while also delivering mycopesticides to adult mosquitoes.


Assuntos
Aedes , Beauveria , Hypocreales , Aedes/fisiologia , Animais , Beauveria/fisiologia , Feminino , Larva/microbiologia , Mosquitos Vetores , Oviposição , Controle Biológico de Vetores , Esporos Fúngicos
9.
J Med Entomol ; 59(5): 1710-1720, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-35861727

RESUMO

Attractive toxic sugar baits (ATSBs) require target insects to locate, orient toward, and feed on an insecticidal sugar solution to control populations. Formulating these baits with different attractants and phagostimulants can increase their efficacy by causing insects to choose the ATSB over competing natural sugar sources, and to ingest more of the bait solution. We tested formulations of a 20% sodium ascorbate (SA) ATSB solution using different sugars, adenosine triphosphate (ATP), gallic acid, and six plant volatile compounds to determine their effect on adult Aedes aegypti (L.) and Anopheles stephensi Liston mortality. Baits formulated with fructose or sucrose had no effect on either species, neither did the addition of ATP. Gallic acid increased the survival of Ae. aegypti. Four of the six volatile compounds increased mortality in at least one species. We also examined An. stephensi response to baits formulated with each of the six volatile compounds. Anisaldehyde significantly increased the number of mosquitoes responding toward the SA-ATSB, but increasing the amount had no effect. Addition of anisaldehyde also significantly increased An. stephensi feeding rates on the SA-ATSB, though mosquitoes will avoid the toxic bait if a nontoxic sugar source is available. Formulation of SA-ATSBs with synthetic blends of attractive compounds can increase bait efficacy and consistency, though further research is needed to assess their performance in the field in the presence of natural sugar sources.


Assuntos
Aedes , Anopheles , Inseticidas , Trifosfato de Adenosina , Aedes/fisiologia , Animais , Anopheles/fisiologia , Ácido Ascórbico/farmacologia , Benzaldeídos , Carboidratos , Ácido Gálico , Inseticidas/farmacologia , Controle de Mosquitos , Açúcares
10.
Parasit Vectors ; 15(1): 260, 2022 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-35858924

RESUMO

BACKGROUND: The rapid worldwide spreading of Aedes aegypti and Aedes albopictus is expanding the risk of arboviral diseases transmission, pointing out the urgent need to improve monitoring and control of mosquito vector populations. Assessment of human-vector contact, currently estimated by classical entomological methods, is crucial to guide planning and implementation of control measures and evaluate transmission risk. Antibody responses to mosquito genus-specific salivary proteins are emerging as a convenient complementary tool for assessing host exposure to vectors. We previously showed that IgG responses to the Ae. albopictus 34k2 salivary protein (al34k2) allow detection of seasonal and geographic variation of human exposure to the tiger mosquito in two temperate areas of Northeast Italy. The main aim of this study was to confirm and extend these promising findings to tropical areas with ongoing arboviral transmission. METHODS: IgG responses to al34k2 and to the Ae. aegypti orthologous protein ae34k2 were measured by ELISA in cohorts of subjects only exposed to Ae. albopictus (Réunion Island), only exposed to Ae. aegypti (Bolivia) or unexposed to both these vectors (North of France). RESULTS AND CONCLUSION: Anti-al34k2 IgG levels were significantly higher in sera of individuals from Réunion Island than in unexposed controls, indicating that al34k2 may be a convenient and reliable proxy for whole saliva or salivary gland extracts as an indicator of human exposure to Ae. albopictus. Bolivian subjects, exposed to bites of Ae. aegypti, carried in their sera IgG recognizing the Ae. albopictus al34k2 protein, suggesting that this salivary antigen can also detect, even though with low sensitivity, human exposure to Ae. aegypti. On the contrary, due to the high background observed in unexposed controls, the recombinant ae34k2 appeared not suitable for the evaluation of human exposure to Aedes mosquitoes. Overall, this study confirmed the suitability of anti-al34k2 IgG responses as a specific biomarker of human exposure to Ae. albopictus and, to a certain extent, to Ae. aegypti. Immunoassays based on al34k2 are expected to be especially effective in areas where Ae. albopictus is the main arboviral vector but may also be useful in areas where Ae. albopictus and Ae. aegypti coexist.


Assuntos
Aedes , Arbovírus , Aedes/fisiologia , Animais , Biomarcadores , Bolívia , Humanos , Imunoglobulina G , Proteínas de Insetos/genética , Mosquitos Vetores , Reunião , Proteínas e Peptídeos Salivares
11.
Curr Biol ; 32(16): 3493-3504.e11, 2022 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-35835123

RESUMO

The mosquito proboscis is an efficient microelectromechanical system, which allows the insect to feed on vertebrate blood quickly and painlessly. Its efficiency is further enhanced by the insect saliva, although through unclear mechanisms. Here, we describe the initial trigger of an unprecedented feedback signaling pathway in Aedes mosquitoes affecting feeding behavior. We identified LIPS proteins in the saliva of Aedes mosquitoes that promote feeding in the vertebrate skin. LIPS show a new all-helical protein fold constituted by two domains. The N-terminal domain interacts with a cuticular protein (Cp19) located at the tip of the mosquito labrum. Upon interaction, the morphology of the labral cuticle changes, and this modification is most likely sensed by proprioceptive neurons. Our study identifies an additional role of mosquito saliva and underlines that the external cuticle is a possible site of key molecular interactions affecting the insect biology and its vector competence.


Assuntos
Aedes , Mosquitos Vetores , Aedes/fisiologia , Animais , Comportamento Alimentar , Saliva , Pele
12.
Med Vet Entomol ; 36(3): 309-319, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35869781

RESUMO

The response to recent dengue outbreaks in Burkina Faso was insecticide-based, despite poor knowledge of the vector population's susceptibility to the insecticides used. Here, we report on the susceptibility to the main insecticide classes and identify important underlying mechanisms in Aedes aegypti populations in Ouagadougou and Banfora, in 2019 and 2020. Wild Ae. aegypti were tested as adults in WHO bioassays and then screened in real time melting curve qPCR analyses to genotype the F1534C, V1016I, and V410L Aedes kdr mutations. Ae. aegypti showed moderate resistance to 0.1% bendiocarb (80-95% survival post-exposure), 0.8% Malathion (60-100%), 0.21% pirimiphos-methyl (75% - 97%), and high resistance to 0.03% deltamethrin (20-70%). PBO pre-exposure partially restored pyrethroid susceptibility. Genotyping detected high frequency of 1534C allele (0.92) and moderate 1016I (0.1-0.32). The V410L mutation was detected in Burkina Faso for the first time (frequency 0.1-0.36). Mosquitoes surviving 4 h exposure to 0.03% deltamethrin had significantly higher frequencies of the F1534C mutation than dead mosquitoes (0.70 vs. 0.96, p < 0.0001) and mosquitoes surviving 2 - 4 h exposure had a significantly reduced life span. Ae. aegypti from Burkina Faso are resistant to multiple insecticide classes with multiple mechanisms involved, demonstrating the essential role of insecticide resistance monitoring within national dengue control programmes.


Assuntos
Aedes , Dengue , Inseticidas , Piretrinas , Aedes/fisiologia , Animais , Burkina Faso , Dengue/prevenção & controle , Dengue/veterinária , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mosquitos Vetores/genética , Mutação , Piretrinas/farmacologia
13.
PLoS Negl Trop Dis ; 16(6): e0010478, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35700164

RESUMO

BACKGROUND: Vector surveillance is an essential public health tool to aid in the prediction and prevention of mosquito borne diseases. This study compared spatial and temporal trends of vector surveillance indices for Aedes vectors in the southern Philippines, and assessed potential links between vector indices and climate factors. METHODS: We analysed routinely collected larval and pupal surveillance data from residential areas of 14 cities and 51 municipalities during 2013-2018 (House, Container, Breteau and Pupal Indices), and used linear regression to explore potential relationships between vector indices and climate variables (minimum temperature, maximum temperature and precipitation). RESULTS: We found substantial spatial and temporal variation in monthly Aedes vector indices between cities during the study period, and no seasonal trend apparent. The House (HI), Container (CI) and Breteau (BI) Indices remained at comparable levels across most surveys (mean HI = 15, mean CI = 16, mean BI = 24), while the Pupal Productivity Index (PPI) was relatively lower in most months (usually below 5) except for two main peak periods (mean = 49 overall). A small proportion of locations recorded high values across all entomological indices in multiple surveys. Each of the vector indices were significantly correlated with one or more climate variables when matched to data from the same month or the previous 1 or 2 months, although the effect sizes were small. Significant associations were identified between minimum temperature and HI, CI and BI in the same month (R2 = 0.038, p = 0.007; R2 = 0.029, p = 0.018; and R2 = 0.034, p = 0.011, respectively), maximum temperature and PPI with a 2-month lag (R2 = 0.031, p = 0.032), and precipitation and HI in the same month (R2 = 0.023, p = 0.04). CONCLUSIONS: Our findings indicated that larval and pupal surveillance indices were highly variable, were regularly above the threshold for triggering vector control responses, and that vector indices based on household surveys were weakly yet significantly correlated with city-level climate variables. We suggest that more detailed spatial and temporal analyses of entomological, climate, socio-environmental and Aedes-borne disease incidence data are necessary to ascertain the most effective use of entomological indices in guiding vector control responses, and reduction of human disease risk.


Assuntos
Aedes , Dengue , Aedes/fisiologia , Animais , Humanos , Larva , Controle de Mosquitos , Mosquitos Vetores/fisiologia , Filipinas/epidemiologia
14.
Proc Natl Acad Sci U S A ; 119(25): e2202932119, 2022 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-35696563

RESUMO

The primary insect steroid hormone ecdysone requires a membrane transporter to enter its target cells. Although an organic anion-transporting polypeptide (OATP) named Ecdysone Importer (EcI) serves this role in the fruit fly Drosophila melanogaster and most likely in other arthropod species, this highly conserved transporter is apparently missing in mosquitoes. Here we report three additional OATPs that facilitate cellular incorporation of ecdysone in Drosophila and the yellow fever mosquito Aedes aegypti. These additional ecdysone importers (EcI-2, -3, and -4) are dispensable for development and reproduction in Drosophila, consistent with the predominant role of EcI. In contrast, in Aedes, EcI-2 is indispensable for ecdysone-mediated development, whereas EcI-4 is critical for vitellogenesis induced by ecdysone in adult females. Altogether, our results indicate unique and essential functions of these additional ecdysone importers in mosquito development and reproduction, making them attractive molecular targets for species- and stage-specific control of ecdysone signaling in mosquitoes.


Assuntos
Aedes , Ecdisona , Proteínas de Insetos , Transportadores de Ânions Orgânicos , Aedes/crescimento & desenvolvimento , Aedes/fisiologia , Animais , Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Ecdisona/metabolismo , Feminino , Proteínas de Insetos/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Vitelogênese
15.
Proc Natl Acad Sci U S A ; 119(25): e2204238119, 2022 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-35700364

RESUMO

The Anthropocene Epoch poses a critical challenge for organisms: they must cope with new threats at a rapid rate. These threats include toxic chemical compounds released into the environment by human activities. Here, we examine elevated concentrations of heavy metal ions as an example of anthropogenic stressors. We find that the fruit fly Drosophila avoids nine metal ions when present at elevated concentrations that the flies experienced rarely, if ever, until the Anthropocene. We characterize the avoidance of feeding and egg laying on metal ions, and we identify receptors, neurons, and taste organs that contribute to this avoidance. Different subsets of taste receptors, including members of both Ir (Ionotropic receptor) and Gr (Gustatory receptor) families contribute to the avoidance of different metal ions. We find that metal ions activate certain bitter-sensing neurons and inhibit sugar-sensing neurons. Some behavioral responses are mediated largely through neurons of the pharynx. Feeding avoidance remains stable over 10 generations of exposure to copper and zinc ions. Some responses to metal ions are conserved across diverse dipteran species, including the mosquito Aedes albopictus. Our results suggest mechanisms that may be essential to insects as they face challenges from environmental changes in the Anthropocene.


Assuntos
Efeitos Antropogênicos , Drosophila melanogaster , Exposição Ambiental , Reação de Fuga , Metais Pesados , Percepção Gustatória , Paladar , Aedes/fisiologia , Animais , Aprendizagem da Esquiva , Cátions/toxicidade , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiologia , Humanos , Metais Pesados/toxicidade , Receptores Ionotrópicos de Glutamato/metabolismo , Paladar/fisiologia , Percepção Gustatória/fisiologia
16.
J Am Mosq Control Assoc ; 38(2): 99-103, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35588180

RESUMO

As part of an arbovirus vector control strategy, chemical control continues to be a mainstay in mitigating the burden of disease. The current arsenal of chemicals used for this purpose, however, are becoming challenged rapidly because of issues of insecticide resistance and environmental pressure. Newer, environmentally friendly actives are of interest to supplement aging chemistries; therefore efforts to screen compounds for insecticidal activity are warranted. This study evaluated the efficacy of the high-throughput screening system (HITSS) for measuring the behavior-modifying actions of Brazilian Cerrado plant extracts, oils, and other compounds against Aedes aegypti. Different concentrations were evaluated, with 8 of 34 samples tested demonstrating either contact irritancy, spatial repellency, or attractiveness. We concluded several natural products screened in this study showed promise for use against mosquito vectors like Ae. aegypti, and that the compact modular HITSS assay constitutes a robust tool for measuring the behavioral responses of mosquitoes in the search for novel insecticides derived from natural products.


Assuntos
Aedes , Produtos Biológicos , Repelentes de Insetos , Inseticidas , Aedes/fisiologia , Animais , Feminino , Ensaios de Triagem em Larga Escala , Controle de Mosquitos , Mosquitos Vetores
17.
BMC Biol ; 20(1): 110, 2022 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-35549721

RESUMO

BACKGROUND: Mosquitoes locate a human host by integrating various sensory cues including odor, thermo, and vision. However, their innate light preference and its genetic basis that may predict the spatial distribution of mosquitoes, a prerequisite to encounter a potential host and initiate host-seeking behaviors, remains elusive. RESULTS: Here, we first studied mosquito visual features and surprisingly uncovered that both diurnal (Aedes aegypti and Aedes albopictus) and nocturnal (Culex quinquefasciatus) mosquitoes significantly avoided stronger light when given choices. With consistent results from multiple assays, we found that such negative phototaxis maintained throughout development to adult stages. Notably, female mosquitoes significantly preferred to bite hosts in a shaded versus illuminated area. Furthermore, silencing Opsin1, a G protein-coupled receptor that is most enriched in compound eyes, abolished light-evoked avoidance behavior of Aedes albopictus and attenuated photonegative behavior in Aedes aegypti. Finally, we found that field-collected Aedes albopictus also prefers darker area in an Opsin1-dependent manner. CONCLUSIONS: This study reveals that mosquitoes consistently prefer darker environment and identifies the first example of a visual molecule that modulates mosquito photobehavior.


Assuntos
Aedes , Culex , Aedes/fisiologia , Animais , Aprendizagem da Esquiva , Culex/fisiologia , Comportamento Alimentar , Feminino , Humanos
18.
Elife ; 112022 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-35550041

RESUMO

Predatory animals pursue prey in a noisy sensory landscape, deciding when to continue or abandon their chase. The mosquito Aedes aegypti is a micropredator that first detects humans at a distance through sensory cues such as carbon dioxide. As a mosquito nears its target, it senses more proximal cues such as body heat that guide it to a meal of blood. How long the search for blood continues after initial detection of a human is not known. Here, we show that a 5 s optogenetic pulse of fictive carbon dioxide induced a persistent behavioral state in female mosquitoes that lasted for more than 10 min. This state is highly specific to females searching for a blood meal and was not induced in recently blood-fed females or in males, who do not feed on blood. In males that lack the gene fruitless, which controls persistent social behaviors in other insects, fictive carbon dioxide induced a long-lasting behavior response resembling the predatory state of females. Finally, we show that the persistent state triggered by detection of fictive carbon dioxide enabled females to engorge on a blood meal mimic offered up to 14 min after the initial 5 s stimulus. Our results demonstrate that a persistent internal state allows female mosquitoes to integrate multiple human sensory cues over long timescales, an ability that is key to their success as an apex micropredator of humans.


Assuntos
Aedes , Comportamento Predatório , Aedes/fisiologia , Animais , Dióxido de Carbono , Sinais (Psicologia) , Feminino , Humanos , Masculino
19.
PLoS One ; 17(5): e0267278, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35536780

RESUMO

BACKGROUND: With the recent occurrence of locally transmitted Aedes-borne viruses in the continental United States and Europe, and a lack of effective vaccines, new approaches to control Aedes aegypti and Aedes albopictus are needed. In sub-tropical urban settings in the US, Ae. albopictus is a dominant nuisance and arbovirus vector species. Unfortunately, the vector control toolbox against Ae. albopictus is not as well developed as for Ae. aegypti. Here, we evaluate the efficacy, longevity, and range of protectiveness of a novel passive metofluthrin emanator (10% active ingredient in a polyethylene mesh) against Ae. albopictus indoors and outdoors. METHODS: Four studies were conducted comparing the presence of the metofluthrin emanator to a control lacking emanator with interest in quantifying efficacy by human landing counts. Studies evaluated the effect of an emanator at varying distances from one or more human volunteers indoors and outdoors. Efficacy of emanators over time since activation was also evaluated. RESULTS: Mixed-effects models determined that sitting in close proximity to an emanator reduced landings by 89.5% outdoors and by 74.6% indoors. The emanator was determined protective when located immediately next to a human volunteer outdoors but not uniformly protective when located further away. The emanator was protective at all tested distances from the device indoors. Mortality of mosquitoes exposed to metofluthrin emanators was ~2x higher than those who were not exposed in indoor conditions. Finally, a Generalized Additive Model determined that emanators used continuously outdoors lost their effect after 2.5 weeks and stopped inducing paralysis in mosquitoes after 3.8 weeks of use. CONCLUSIONS: We show strong and lasting efficacy of 10% metofluthrin emanators against field Ae. albopictus both in indoor and outdoor conditions. Metofluthrin emanators can protect people from Ae. albopictus bites, representing a viable option for reducing human-mosquito contacts at home and beyond.


Assuntos
Aedes , Inseticidas , Aedes/fisiologia , Animais , Ciclopropanos , Fluorbenzenos , Humanos , Inseticidas/farmacologia , Controle de Mosquitos , Mosquitos Vetores
20.
J Insect Sci ; 22(3)2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35526103

RESUMO

The control of mosquito populations using insecticides is increasingly threatened by the spread of resistance mechanisms. Dieldrin resistance, conferred by point mutations in the Rdl gene encoding the γ-aminobutyric acid receptor, has been reported at high prevalence in mosquito populations in response to selective pressures. In this study, we monitored spatio-temporal dynamics of the resistance-conferring RdlR allele in Aedes (Stegomyia) albopictus (Skuse, 1895) and Culex (Culex) quinquefasciatus (Say, 1823) populations from Reunion Island. Specimens of both mosquito species were sampled over a 12-month period in three cities and in sites located at lower (<61 m) and higher (between 503 and 564 m) altitudes. Mosquitoes were genotyped using a molecular test detecting the alanine to serine substitution (A302S) in the Rdl gene. Overall, the RdlR frequencies were higher in Cx. quinquefasciatus than Ae. albopictus. For both mosquito species, the RdlR frequencies were significantly influenced by location and altitude with higher RdlR frequencies in the most urbanized areas and at lower altitudes. This study highlights environmental factors that influence the dynamics of insecticide resistance genes, which is critical for the management of insecticide resistance and the implementation of alternative and efficient vector control strategies.


Assuntos
Aedes , Culex , Inseticidas , Aedes/fisiologia , Animais , Culex/genética , Dieldrin , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mosquitos Vetores/genética , Reunião
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...