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Muturi EJ, Hay WT, Doll KM, Ramirez JL, Selling G. Insecticidal Activity of Commiphora erythraea Essential Oil and Its Emulsions Against Larvae of Three Mosquito Species. J Med Entomol 2020; 57:1835-1842. [PMID: 32474606 DOI: 10.1093/jme/tjaa097] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Indexed: 06/11/2023]
Abstract
The use of essential oils as ecofriendly tools for vector management is one of the mainstreams for biopesticide research. We evaluated the larvicidal properties of Commiphora erythraea (opoponax) essential oil and its fractions against Culex restuans Theobald, Culex pipiens L., and Aedes aegypti L. The use of bio-based amylose-N-1-hexadecylammonium chloride inclusion complex (Hex-Am) and amylose-sodium palmitate inclusion complex (Na-Palm) as emulsifiers for C. erythraea essential oil was also investigated. Bisabolene was the most abundant chemical constituent in the whole essential oil (33.9%), fraction 2 (62.5%), and fraction 4 (23.8%) while curzerene (32.6%) and α-santalene (30.1%) were the dominant chemical constituents in fractions 1 and 3, respectively. LC50 values for the whole essential oil were 19.05 ppm for Cx. restuans, 22.61 ppm for Cx. pipiens, and 29.83 ppm for Ae. aegypti and differed significantly. None of the four C. erythraea essential oil fractions were active against mosquito larvae. Two CYP450 genes (CYP6M11 and CYP6N12) and one GST gene (GST-2) were significantly upregulated in Ae. aegypti larvae exposed to C. erythraea essential oil suggesting their potential involvement in metabolic pathways for C. erythraea essential oil. Essential oil emulsions produced with Hex-Am were more toxic than the whole essential oil while those produced with Na-Palm had similar toxicity as the whole essential oil. These findings demonstrate that C. erythraea essential oil is a promising source of mosquito larvicide and that the use of Hex-Am as an emulsifier can enhance the insecticidal properties of C. erythraea essential oil.
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Affiliation(s)
- Ephantus J Muturi
- USDA, Agricultural Research Service, NCAUR, Crop Bioprotection Research Unit, Peoria, IL
| | - William T Hay
- USDA, Agricultural Research Service, NCAUR, Mycotoxin Prevention and Applied Microbiology Research Unit, Peoria, IL
| | - Kenneth M Doll
- USDA, Agricultural Research Service, NCAUR, Bio-Oils Research Unit, Peoria, IL
| | - Jose L Ramirez
- USDA, Agricultural Research Service, NCAUR, Crop Bioprotection Research Unit, Peoria, IL
| | - Gordon Selling
- USDA, Agricultural Research Service, NCAUR, Plant Polymer Research Unit, Peoria, IL
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González-Villarreal SE, García-Montelongo M, Ibarra JE. Insecticidal Activity of a Cry1Ca toxin of Bacillus thuringiensis Berliner (Firmicutes: Bacillaceae) and Its Synergism with the Cyt1Aa Toxin Against Aedes aegypti (Diptera: Culicidae). J Med Entomol 2020; 57:1852-1856. [PMID: 32537634 DOI: 10.1093/jme/tjaa116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Indexed: 06/11/2023]
Abstract
The Cry1C protein family of Bacillus thuringiensis form bipyramidal crystals, which are commonly associated with toxic activity against lepidopteran species; however, some members of this family may also be toxic to dipterans. In the present work, the Cry1Ca16 protein, synthesized by the B. thuringiensis LBIT-1217 strain, was analyzed. The gene coding for this protein was amplified, sequenced, and cloned into the pSTAB vector, which was electro-transferred into the acrystalliferous B. thuringiensis 4Q7 strain. The recombinant strain showed the expected bipyramidal crystal morphology, identical to the original LBIT-1217 strain and exhibited toxicity against larvae of Aedes aegypti (Diptera). Pure crystals from the recombinant strain were used in bioassays against Ae. aegypti larvae, estimating an LC50 of 4.61 μg/ml. Further studies on Cry1Ca16 mosquitocidal potential included joint-action tests with the Cyt1Aa protein crystals from B. thuringiensis israelensis. An LC50 using pure Cyt1Aa crystals was estimated at 0.73 μg/ml, whereas an LC50 of 0.61 μg/ml was estimated when both toxins were tested together. Data from these bioassays was analyzed using joint-action tests such as the Tammes-Bakuniak graphical method and the formula proposed by Tabashnik (1992). Both tests clearly showed a synergistic effect between these two toxins.
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Affiliation(s)
| | - Mónica García-Montelongo
- Centro de Investigación y Estudios Avanzados del IPN, Unidad Irapuato, Irapuato, Guanajuato, Mexico
| | - Jorge E Ibarra
- Centro de Investigación y Estudios Avanzados del IPN, Unidad Irapuato, Irapuato, Guanajuato, Mexico
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53
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Hernández-Rodríguez JL, Perez-Pacheco R, Vásquez-López A, Mejenes-Hernández MC, Granados-Echegoyen CA, Arcos-Cordova IDR, Pérez-Rentería C, Benítez-Alva JI, Manrique-Saide P, Huerta H. Asian Tiger Mosquito in Yucatan Peninsula: First Record of Aedes (Stegomyia) albopictus (Diptera: Culicidae) in Campeche, Mexico. J Med Entomol 2020; 57:2022-2024. [PMID: 32623458 DOI: 10.1093/jme/tjaa133] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Indexed: 06/11/2023]
Abstract
This report describes the presence of Aedes albopictus Skuse (Diptera: Culicidae) in Yucatan Peninsula and represents the first record of the Asian tiger invasive mosquito in Campeche State, southeastern Mexico. We collected specimens using 11,326 ovitraps put into houses of urban and rural areas, as part of the entomological surveillance by the local Ministry of Health from January 2019 to February 2020. We found Ae. albopictus in five of the 12 municipalities of Campeche (San Francisco de Campeche, Tenabo, Hecelchakán, Calkíni and Escárcega). We record 68 positive ovitraps and 226 Ae. albopictus larvae. This finding increases the number of mosquito species recorded in Campeche, Mexico, and possibly the potential for 22 arbovirus transmission.
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Affiliation(s)
| | - Rafael Perez-Pacheco
- Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional Unidad Oaxaca (CIIDIR Oaxaca), Instituto Politécnico Nacional, Santa Cruz Xoxocotlán, Oaxaca, Mexico
| | - Alfonso Vásquez-López
- Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional Unidad Oaxaca (CIIDIR Oaxaca), Instituto Politécnico Nacional, Santa Cruz Xoxocotlán, Oaxaca, Mexico
| | | | - Carlos Alejandro Granados-Echegoyen
- Centro de Estudios en Desarrollo Sustentable y Aprovechamiento de la Vida Silvestre (CEDESU), CONACYT-Universidad Autónoma de Campeche, San Francisco de Campeche, Campeche, Mexico
| | | | - Crescencio Pérez-Rentería
- Laboratorio de Entomología, Instituto de Diagnóstico y Referencia Epidemiológicos, Ciudad de Mexico, Mexico
| | - José I Benítez-Alva
- Laboratorio de Entomología, Instituto de Diagnóstico y Referencia Epidemiológicos, Ciudad de Mexico, Mexico
| | - Pablo Manrique-Saide
- Unidad Colaborativa para Bioensayos Entomológicos, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Mexico
| | - Herón Huerta
- Laboratorio de Entomología, Instituto de Diagnóstico y Referencia Epidemiológicos, Ciudad de Mexico, Mexico
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Westby KM, Medley KA. Cold Nights, City Lights: Artificial Light at Night Reduces Photoperiodically Induced Diapause in Urban and Rural Populations of Aedes albopictus (Diptera: Culicidae). J Med Entomol 2020; 57:1694-1699. [PMID: 32638000 DOI: 10.1093/jme/tjaa139] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Indexed: 05/12/2023]
Abstract
As the planet becomes increasingly urbanized, it is imperative that we understand the ecological and evolutionary consequences of urbanization on species. One common attribute of urbanization that differs from rural areas is the prevalence of artificial light at night (ALAN). For many species, light is one of the most important and reliable environmental cues, largely governing the timing of daily and seasonal activity patterns. Recently, it has been shown that ALAN can alter behavioral, phenological, and physiological traits in diverse taxa. For temperate insects, diapause is an essential trait for winter survival and commences in response to declining daylight hours in the fall. Diapause is under strong selection pressure in the mosquito, Aedes albopictus (Skuse); local adaptation and rapid evolution has been observed along a latitudinal cline. It is unknown how ALAN affects this photosensitive trait or if local adaptation has occurred along an urbanization gradient. Using a common garden experiment, we experimentally demonstrated that simulated ALAN reduces diapause incidence in this species by as much as 40%. There was no difference, however, between urban and rural demes. We also calculated diapause incidence from wild demes in urban areas to determine whether wild populations exhibited lower than predicted incidence compared to estimates from total nocturnal darkness. In early fall, lower than predicted diapause incidence was recorded, but all demes reached nearly 100% diapause before terminating egg laying. It is possible that nocturnal resting behavior in vegetation limits the amount of ALAN exposure this species experiences potentially limiting local adaptation.
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Affiliation(s)
- Katie M Westby
- Tyson Research Center, Washington University in Saint Louis, Eureka, MO
| | - Kim A Medley
- Tyson Research Center, Washington University in Saint Louis, Eureka, MO
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Reuss F, Kreß A, Braun M, Magdeburg A, Pfenninger M, Müller R, Mehring M. Knowledge on exotic mosquitoes in Germany, and public acceptance and effectiveness of Bti and two self-prepared insecticides against Aedes japonicus japonicus. Sci Rep 2020; 10:18901. [PMID: 33144626 PMCID: PMC7641113 DOI: 10.1038/s41598-020-75780-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 10/08/2020] [Indexed: 12/05/2022] Open
Abstract
Mosquito-borne diseases are a continuous challenge to public health. To prevent transmission, Integrated Vector Management (IVM) applies preventive, control, and communicational strategies that should be feasible, environmentally benign, and sustainable. IVM shows higher efficiency when being supported by local communities. Accordingly, we applied a social-ecological approach to identify the public acceptance of control measures and effectiveness of Eurocent coins containing copper, clove essential oil (EO) and Bacillus thuringiensis israelensis (Bti). We performed field and laboratory experiments to demonstrate the toxicity of alternative substances against Aedes japonicus japonicus. In expert interviews, we asked for (1) knowledge on exotic mosquitoes in Germany, (2) potential chances of alternative substances in future mosquito control, and (3) their needs for further clarification before application. We assessed potential users' (4) awareness of exotic mosquitoes and (5) willingness to apply the substances. Self-prepared copper coins and EO were clearly preferred by potential users over Bti. However, 100% mortality of the sensitive first stage could not be reached with the number of ten 5-Eurocent coins showing limited toxicity. Clove EO was shown to work as oviposition deterrent and larvicide with a LC50 of 17 mg l-1 (95% CI: 15-19 mg l-1). This study shows the importance of potential users' perspectives in IVM and the need for authorised insecticides.
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Affiliation(s)
- Friederike Reuss
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Georg-Voigt-Straße 14-16, 60325, Frankfurt am Main, Germany.
| | - Aljoscha Kreß
- Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Markus Braun
- Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Axel Magdeburg
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Georg-Voigt-Straße 14-16, 60325, Frankfurt am Main, Germany
- Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Markus Pfenninger
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Georg-Voigt-Straße 14-16, 60325, Frankfurt am Main, Germany
- LOEWE TBG (Translational Biodiversity Genomics), Senckenberganlage 25, 60325, Frankfurt am Main, Germany
- Institute of Organismic and Molecular Evolution (iOME), Johannes Gutenberg University, Gresemundweg 2, 55128, Mainz, Germany
| | - Ruth Müller
- Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
- Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium
| | - Marion Mehring
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Georg-Voigt-Straße 14-16, 60325, Frankfurt am Main, Germany
- ISOE - Institute for Social-Ecological Research, Biodiversity and People, Hamburger Allee 45, 60486, Frankfurt am Main, Germany
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Yu L, Chen X, Wei Y, Ding Y, Wang Q, Wang S, Tang B, Wang S. Effects of long-term cadmium exposure on trehalose metabolism, growth, and development of Aedes albopictus (Diptera: Culicidae). Ecotoxicol Environ Saf 2020; 204:111034. [PMID: 32758695 DOI: 10.1016/j.ecoenv.2020.111034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/10/2020] [Accepted: 07/11/2020] [Indexed: 06/11/2023]
Abstract
Trehalose is the major blood sugar in insects; it not only serves as an energy source but also plays important roles in physiological responses to adverse conditions. However, only a few studies have explored the effects of heavy metal exposure stress on trehalose metabolism in insects. Therefore, in this study, we examined the effects of cadmium stress on changes in trehalose metabolism in Aedes albopictus. Three concentrations of cadmium (0.005, 0.01, and 0.1 mg/L) were selected for evaluation of long-term stress in Ae. albopictus (from eggs to adults); Ae. albopictus in double-distilled water was used as the control group. The trehalose and glucose contents, trehalase activity, and trehalose metabolism-related gene expression were determined. The effects of long-term cadmium exposure on growth, development, and reproduction were also assessed. Trehalose contents were increased, whereas glucose contents and trehalase activity were decreased in Ae. albopictus following long-term exposure to low concentrations of cadmium compared with those in untreated individuals. Moreover, the expression of trehalose-6-phosphate synthase was upregulated, and that of trehalase was downregulated, indicating that Ae. albopictus may enhance trehalose synthesis to resist cadmium stress. Cadmium exposure also caused Ae. albopictus individuals to become smaller with a longer developmental duration, whereas both reproduction and hatching rates of the offspring were decreased compared with those in the control group. Our findings demonstrated that cadmium exposure affected the morphology, physiology, and biochemistry of Ae. albopictus. These findings also confirmed the role of trehalose in the response of Ae. albopictus to cadmium stress, providing insights into the effects of heavy metal stress on trehalose metabolism in an insect model.
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Affiliation(s)
- Lingyuan Yu
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Xumin Chen
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Ying Wei
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yanjuan Ding
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Qiwei Wang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Shaohua Wang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Bin Tang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Shigui Wang
- Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China.
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57
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Hwang MJ, Kim HC, Klein TA, Chong ST, Sim K, Chung Y, Cheong HK. Comparison of climatic factors on mosquito abundance at US Army Garrison Humphreys, Republic of Korea. PLoS One 2020; 15:e0240363. [PMID: 33085720 PMCID: PMC7577452 DOI: 10.1371/journal.pone.0240363] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 09/24/2020] [Indexed: 01/05/2023] Open
Abstract
Introduction A number of studies have been conducted on the relationship between the distribution of mosquito abundance and meteorological variables. However, few studies have specifically provided specific ranges of temperatures for estimating the maximum abundance of mosquitoes as an empirical basis for climatic dynamics for estimating mosquito-borne infectious disease risks. Methods Adult mosquitoes were collected for three consecutive nights/week using Mosquito Magnet® Independence® model traps during 2018 and 2019 at US Army Garrison (USAG) Humphreys, Pyeongtaek, Gyeonggi Province, Republic of Korea (ROK). An estimate of daily mean temperatures (provided by the Korea Meteorological Administration) were distributed at the maximum abundance for selected species of mosquitoes using daily mosquito collection data after controlling for mosquito ecological cycles and environmental factors. Results Using the Monte-Carlo simulation, the overall mosquito population abundance peaked at 22.7°C (2.5th—97.5th: 21.7°C–23.8°C). Aedes albopictus, vector of Zika, chikungunya, dengue fever and other viruses, abundance peaked at 24.6°C (2.5th–97.5th, 22.3°C–25.6°C), while Japanese encephalitis virus (JEV) vectors, e.g., Culex tritaeniorhynchus and Culex pipiens, peaked at 24.3°C (2.5th–97.5th: 21.9°C–26.3°C) and 22.6°C (2.5th–97.5th: 21.9°C–25.2°C), respectively. Members of the Anopheles Hyrcanus Group, some of which are vivax malaria vectors in the ROK, abundance peaked at 22.4°C (2.5th–97.5th: 21.5°C–23.8°C). Conclusion The empirical mean temperature ranges for maximum abundance were determined for each mosquito species collected at USAG Humphreys. These data contributed to the identification of relative mosquito abundance patterns for estimating mosquito-borne disease risks and developing and implementing disease prevention practices.
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Affiliation(s)
- Myung-Jae Hwang
- Department of Social and Preventive Medicine, Sungkyunkwan University School of Medicine, Suwon, Gyeonggi-do, Republic of Korea
| | - Heung-Chul Kim
- Force Health Protection and Preventive Medicine, Medical Department Activity-Korea/65th Medical Brigade, Unit 15281, United States of America
| | - Terry A. Klein
- Force Health Protection and Preventive Medicine, Medical Department Activity-Korea/65th Medical Brigade, Unit 15281, United States of America
| | - Sung-Tae Chong
- Force Health Protection and Preventive Medicine, Medical Department Activity-Korea/65th Medical Brigade, Unit 15281, United States of America
| | - Kisung Sim
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Yeonseung Chung
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Hae-Kwan Cheong
- Department of Social and Preventive Medicine, Sungkyunkwan University School of Medicine, Suwon, Gyeonggi-do, Republic of Korea
- * E-mail:
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58
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Abstract
Male and female mosquito larvae compete for different subsets of the yeast food resource in laboratory microcosms. Males compete more intensely with males, and females with females. The amount and timing of food inputs alters both growth and competition, but the effects are different between sexes. Increased density increases competition among males. Among females, density operates primarily by changing the food/larva or total food; this affects competition in some interactions and growth in others. Food added earlier in the life span contributes more to mass than the same quantity added later. After a period of starvation larvae appear to use some of the subsequent food input to rebuild physiological reserves in addition to building mass. The timing of pupation is affected by the independent factors and competition, but not in the same way for the two sexes, and not in the same way as mass at pupation for the two sexes. There is an effect of density on the timing of pupation for females independent of competition or changes in food/larva or total food. Male and female larvae have different larval life history strategies. Males grow quickly to a minimum size, then pupate, depending on the amount of food available. Males that do not grow quickly enough may delay pupation further to grow larger, resulting in a bimodal distribution of sizes and ages. Males appear to have a maximum size determined by the early food level. Females grow faster than males and grow larger than males on the same food inputs. Females affect the growth and competition among males by manipulating the number of particles in the microcosm through changes in feeding behavior. Mosquito larvae appear to have evolved to survive periods of starvation and take advantage of intermittent inputs of food into containers.
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Affiliation(s)
- Kurt Steinwascher
- Florida Medical Entomology Laboratory, Vero Beach, FL, United States of America
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Javidfar M, Ahmadi S. QSAR modelling of larvicidal phytocompounds against Aedes aegypti using index of ideality of correlation. SAR QSAR Environ Res 2020; 31:717-739. [PMID: 32930630 DOI: 10.1080/1062936x.2020.1806922] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/04/2020] [Indexed: 06/11/2023]
Abstract
Aedes aegypti is the primary vector of several infectious viruses that cause yellow, dengue, chikungunya, and Zika fevers. Recently, plant-derived products have been tested as safe and eco-friendly larvicides against Ae. aegypti. The present study aimed to improve QSAR models for 62 larvicidal phytocompounds against Ae. aegypti via the Monte Carlo method based on the index of the ideality of correlation (IIC) criterion. The representation of structures was done with SMILES. Three splits were prepared randomly and three QSAR models were constructed using IIC target function. The molecular descriptors were selected from SMILES descriptors and the hydrogen-filled molecular graphs. The predictability of three models was evaluated on the validation sets, the r 2 of which was 0.9770, 0.8660, and 0.8565 for models 1 to 3, respectively. The statistical results of three randomized splits indicated that robust, simple, predictive, and reliable models were obtained for different sets. From the modelling results, important descriptors were identified to enhance and reduce the larvicidal activity of compounds. Based on the identified important descriptors, some new structures of larvicidal compounds were proposed. The larvicidal activity of novel molecules designed further was supported by docking studies. Using the simple QSAR model, one can predict pLC50 of new similarity larvicidal phytocompounds.
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Affiliation(s)
- M Javidfar
- Department of Chemistry, Faculty of Pharmaceutical Chemistry, Tehran Medical Sciences, Islamic Azad University , Tehran, Iran
| | - S Ahmadi
- Department of Chemistry, Faculty of Pharmaceutical Chemistry, Tehran Medical Sciences, Islamic Azad University , Tehran, Iran
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60
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Rose NH, Sylla M, Badolo A, Lutomiah J, Ayala D, Aribodor OB, Ibe N, Akorli J, Otoo S, Mutebi JP, Kriete AL, Ewing EG, Sang R, Gloria-Soria A, Powell JR, Baker RE, White BJ, Crawford JE, McBride CS. Climate and Urbanization Drive Mosquito Preference for Humans. Curr Biol 2020; 30:3570-3579.e6. [PMID: 32707056 PMCID: PMC7511451 DOI: 10.1016/j.cub.2020.06.092] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/18/2020] [Accepted: 06/26/2020] [Indexed: 12/24/2022]
Abstract
The majority of mosquito-borne illness is spread by a few mosquito species that have evolved to specialize in biting humans, yet the precise causes of this behavioral shift are poorly understood. We address this gap in the arboviral vector Aedes aegypti. We first collect and characterize the behavior of mosquitoes from 27 sites scattered across the species' ancestral range in sub-Saharan Africa, revealing previously unrecognized variation in preference for human versus animal odor. We then use modeling to show that over 80% of this variation can be predicted by two ecological factors-dry season intensity and human population density. Finally, we integrate this information with whole-genome sequence data from 375 individual mosquitoes to identify a single underlying ancestry component linked to human preference. Genetic changes associated with human specialist ancestry were concentrated in a few chromosomal regions. Our findings suggest that human-biting in this important disease vector originally evolved as a by-product of breeding in human-stored water in areas where doing so provided the only means to survive the long, hot dry season. Our model also predicts that the rapid urbanization currently taking place in Africa will drive further mosquito evolution, causing a shift toward human-biting in many large cities by 2050.
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Affiliation(s)
- Noah H Rose
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA; Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA.
| | - Massamba Sylla
- Unité d'Entomologie, de Bactériologie, de Virologie, Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP BP 5005 Dakar, Senegal
| | - Athanase Badolo
- Laboratory of Fundamental and Applied Entomology, Université Joseph Ki-Zerbo, 03 BP 7021 Ouagadougou, Burkina Faso
| | - Joel Lutomiah
- Arbovirus/Viral Hemorrhagic Fevers Laboratory, Center for Virus Research, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Diego Ayala
- UMR MIVEGEC, IRD, CNRS, Univ. Montpellier, 911 avenue Agropolis, BP 64501, 34394 Montpellier, France; Le Centre International de Recherches Médicales de Franceville, BP 769, Franceville, Gabon
| | | | - Nnenna Ibe
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Jewelna Akorli
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Sampson Otoo
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - John-Paul Mutebi
- Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
| | - Alexis L Kriete
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA; Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA
| | - Eliza G Ewing
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Rosemary Sang
- Arbovirus/Viral Hemorrhagic Fevers Laboratory, Center for Virus Research, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Andrea Gloria-Soria
- Department of Ecology and Evolutionary Biology, Yale University, 21 Sachem Street, New Haven, CT 06511, USA
| | - Jeffrey R Powell
- Department of Ecology and Evolutionary Biology, Yale University, 21 Sachem Street, New Haven, CT 06511, USA
| | - Rachel E Baker
- Princeton Environmental Institute, Princeton University, Princeton, NJ 08544, USA
| | - Bradley J White
- Verily Life Sciences, 259 East Grand Avenue, South San Francisco, CA 94080, USA
| | - Jacob E Crawford
- Verily Life Sciences, 259 East Grand Avenue, South San Francisco, CA 94080, USA
| | - Carolyn S McBride
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA; Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA.
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Shehata AZ, El-Sheikh TM, Shaapan RM, Abdel-Shafy S, Alanazi AD. Ovicidal and Latent Effects of Pulicaria jaubertii (Asteraceae) Leaf Extracts on Aedes aegypti. J Am Mosq Control Assoc 2020; 36:161-166. [PMID: 33600582 DOI: 10.2987/20-6952.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The control of Aedes aegypti with synthetic pesticides may result in adverse effects on wildlife and the environment. Bioactive plant extracts have been proposed as one of the alternatives to chemical pesticides used against mosquitoes. Here, we report on the ovicidal and latent effects of ethanolic, petroleum ether, and chloroform leaf extracts of Pulicaria jaubertii at 25 to 150 ppm each against the life stages of laboratory stain of Ae. aegypti. At 150 ppm, the ethanolic leaf extract resulted in 100% ovicidal activity, followed by petroleum ether extract (74%), and chloroform extract about 7% mortality. The ethanolic extract produced 100% larval and pupal mortality at both 75 and 50 ppm, while the petroleum ether extract produced 76.5 and 58.3%, respectively. The ethanolic extract recorded the highest percentage of adult mortality (72.7%) at the lowest concentration (25 ppm). At 25 and 50 ppm, the ethanolic extract resulted in 62.2 and 85.2% sterility index of Ae. aegypti females, respectively, as compared with the 0.1 and 3.5% sterility index caused by the chloroform extract at the same concentrations. In conclusion, P. jaubertii appears to have potential to be further evaluated as a mosquito control agent. Additional studies are needed on its mode of action, synergism with other products, and efficacy under actual field conditions.
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Marten AD, Stothard AI, Kalera K, Swarts BM, Conway MJ. Validamycin A Delays Development and Prevents Flight in Aedes aegypti (Diptera: Culicidae). J Med Entomol 2020; 57:1096-1103. [PMID: 31982917 PMCID: PMC7334893 DOI: 10.1093/jme/tjaa004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Indexed: 06/07/2023]
Abstract
Trehalose is a disaccharide that is the major sugar found in insect hemolymph fluid. Trehalose provides energy, and promotes growth, metamorphosis, stress recovery, chitin synthesis, and insect flight. The hydrolysis of trehalose is under the enzymatic control of the enzyme trehalase. Trehalase is critical to the role of trehalose in insect physiology, and is required for the regulation of metabolism and glucose generation. Trehalase inhibitors represent a novel class of insecticides that have not been fully developed. Here, we tested the ability of trehalose analogues to function as larvacides or adulticides in an important disease vector-Aedes aegypti. We show that validamycin A, but not 5-thiotrehalose, delays larval and pupal development and prevents flight of adult mosquitoes. Larval mosquitoes treated with validamycin A were hypoglycemic and pupae had increased levels of trehalose. Treatment also skewed the sex ratio toward male mosquitoes. These data reveal that validamycin A is a mosquito adulticide that can impair normal development of an important disease vector.
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Affiliation(s)
- Andrew D Marten
- Central Michigan University College of Medicine, Foundational Sciences, Mount Pleasant, MI
| | - Alicyn I Stothard
- Central Michigan University, Department of Chemistry and Biochemistry, Mount Pleasant, MI
| | - Karishma Kalera
- Central Michigan University, Department of Chemistry and Biochemistry, Mount Pleasant, MI
| | - Benjamin M Swarts
- Central Michigan University, Department of Chemistry and Biochemistry, Mount Pleasant, MI
| | - Michael J Conway
- Central Michigan University College of Medicine, Foundational Sciences, Mount Pleasant, MI
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Saeung M, Ngoen-Klan R, Thanispong K, Muenworn V, Bangs MJ, Chareonviriyaphap T. Susceptibility of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) to Temephos in Thailand and Surrounding Countries. J Med Entomol 2020; 57:1207-1220. [PMID: 32159772 DOI: 10.1093/jme/tjaa035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Indexed: 06/10/2023]
Abstract
Aedes-borne virus disease control relies on insecticides to interrupt transmission. Temephos remains a key chemical for control of immature stage Aedes in Thailand and much of Southeast Asia. However, repeated use of insecticides may result in selection for resistance in vector populations, thus compromising operational intervention. Herein, the phenotypic response to temephos by Aedes aegypti (L.) and Aedes albopictus (Skuse) collected in Thailand and surrounding countries is presented. Data from 345 collection sites are included: 283 from literature review (244 sites with Ae. aegypti, 21 with Ae. albopictus, and 18 having both species sampled), plus 62 locations with Ae. aegypti in Thailand conducted between 2014 and 2018. Susceptibility assays followed WHO guidelines using the recommended discriminating dose of temephos (0.012 mg/liter) against late third to early fourth instar Ae. aegypti. Findings revealed 34 locations with susceptible Ae. aegypti, 13 with suspected resistance, and 15 indicating resistance. Published data between 1999 and 2019 in Thailand found Ae. aegypti resistant in 73 of 206 collection sites, whereas 3 locations from 11 sampled with low-level resistant in Ae. albopictus. From surrounding countries conducting temephos assays (Cambodia, Lao PDR, Myanmar, Malaysia, and Singapore), resistance is present in Ae. aegypti and Ae. albopictus from 27 of 56 and 19 of 28 locations, respectively. Routine insecticide susceptibility monitoring should be an operational requirement in vector control programs. Given the wide distribution and apparent increase in temephos-resistance, alternative larvicidal compounds must be considered if chemical control is to remain a viable vector control strategy.
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Affiliation(s)
- Manop Saeung
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Ratchadawan Ngoen-Klan
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Kanutcharee Thanispong
- Division of Vector Borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | - Vithee Muenworn
- Department of Entomology and Plant Pathology, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand
| | - Michael J Bangs
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
- Public Health & Malaria Control Department, PT Freeport Indonesia/International SOS, Kuala Kencana, Papua, Indonesia
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Noh MY, Kim SH, Gorman MJ, Kramer KJ, Muthukrishnan S, Arakane Y. Yellow-g and Yellow-g2 proteins are required for egg desiccation resistance and temporal pigmentation in the Asian tiger mosquito, Aedes albopictus. Insect Biochem Mol Biol 2020; 122:103386. [PMID: 32315743 DOI: 10.1016/j.ibmb.2020.103386] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/17/2020] [Accepted: 04/08/2020] [Indexed: 06/11/2023]
Abstract
Eggs from Aedes mosquitoes exhibit desiccation resistance that helps them to survive and spread as human disease vectors throughout the world. Previous studies have suggested that eggshell/chorion melanization and/or serosal cuticle formation are important for desiccation resistance. In this study, using dsRNAs for target genes, we analyzed the functional importance of two ovary-specific yellow genes, AalY-g and AalY-g2, in the resistance to egg desiccation of the Asian tiger mosquito, Aedes albopictus, a species in which neither the timing of the melanization nor temporal development of the serosal cuticle is correlated with desiccation resistance. Injections of dsAalY-g, dsAalY-g2 or dsAalY-g/g2 (co-injection) into adult females have no effect on their fecundity. However, initial melanization is delayed by 1-2 h with the eggshells eventually becoming black similar to that observed in eggs from dsEGFP-injected control females. In addition, the shape of the eggs from dsAalY-g, -g2 and -g/g2-treated females is abnormally crescent-shaped and the outermost exochorion is more fragile and partially peeled off. dsEGFP control eggs, like those from the wild-type strain, acquire resistance to desiccation between 18 and 24 h after oviposition (HAO). In contrast, ~80% of the 24 HAO dsAalY-g and dsAalY-g2 eggs collapse when they are transferred to a low humidity environment. In addition, there is no electron-dense outer endochorion evident in either dsAalY-g or dsAalY-g2 eggs. These results support the hypothesis that AalY-g and AalY-g2 regulate the timing of eggshell darkening and are required for integrity of the exochorion as well as for rigidity, normal morphology and formation of the outer endochorion, a structure that apparently is critical for desiccation resistance of the Ae. albopictus egg.
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Affiliation(s)
- Mi Young Noh
- Department of Forestry, Chonnam National University, Gwangju, 500-757, South Korea.
| | - Sung Hyun Kim
- Department of Applied Biology, Chonnam National University, Gwangju, 500-757, South Korea
| | - Maureen J Gorman
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Chalmers Hall, Manhattan, KS, 66506, USA
| | - Karl J Kramer
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Chalmers Hall, Manhattan, KS, 66506, USA
| | - Subbaratnam Muthukrishnan
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Chalmers Hall, Manhattan, KS, 66506, USA
| | - Yasuyuki Arakane
- Department of Applied Biology, Chonnam National University, Gwangju, 500-757, South Korea.
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Yoshimura R, Suetsugu T, Kawahara A, Nakata K, Shikata M, Tanaka S, Ono T, Fushiki D, Endo Y. Formation of functional innexin hemichannels, as well as gap junctional channels, in an insect cell line, NIAs-AeAl-2, derived from Asian tiger mosquito Aedes albopictus (Diptera: Culicidae): A partial but significant contribution of innexin 2. J Insect Physiol 2020; 124:104060. [PMID: 32446763 DOI: 10.1016/j.jinsphys.2020.104060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 05/18/2020] [Accepted: 05/18/2020] [Indexed: 06/11/2023]
Abstract
In vertebrates, gap junctions and hemichannels consisting of connexins are important cell surface structures for communication with neighboring cells and for the regulation of various cell functions. To date, various gap-junction-related proteins have been found, including innexins in invertebrates and pannexins in vertebrates. Significant contributions of gap junctions by innexins and (hemi-)channels by pannexins to numerous functions have been reported. Verification of the presence and functional significance of innexin hemichannels, however, remains a gap in our knowledge in innexin physiology. In this study, we revealed the localization of an innexin protein (innexin 2) on the cell surface in mosquito tissues and cultured cells. Furthermore, we demonstrated the presence of functional hemichannels, as well as gap junctions, in mosquito cells using dye transfer assays. The inward uptake of fluorescent dye was inhibited by anti-innexin 2 antibody. These results suggest that innexin hemichannels are formed to function in cultured mosquito cells, in at least a partially innexin 2-dependent manner. Although only a few studies on insect hemichannels have been published, innexin-based hemichannels, as well as innexin gap junctions, could also significantly contribute to insect intercellular signal transduction.
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Affiliation(s)
- Ryoichi Yoshimura
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Kyoto 606-8585, Japan.
| | - Taeko Suetsugu
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Kyoto 606-8585, Japan; Laboratory for Cell Asymmetry, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-Ku, Kobe, Hyogo 650-0047, Japan
| | - Ai Kawahara
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Kyoto 606-8585, Japan
| | - Kana Nakata
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Kyoto 606-8585, Japan
| | - Masato Shikata
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Kyoto 606-8585, Japan
| | - Souma Tanaka
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Kyoto 606-8585, Japan
| | - Tsutomu Ono
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Kyoto 606-8585, Japan
| | - Daisuke Fushiki
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Kyoto 606-8585, Japan
| | - Yasuhisa Endo
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Kyoto 606-8585, Japan
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Aragão FV, Cavicchioli Zola F, Nogueira Marinho LH, De Genaro Chiroli DM, Braghini Junior A, Colmenero JC. Choice of unmanned aerial vehicles for identification of mosquito breeding sites. Geospat Health 2020; 15. [PMID: 32575963 DOI: 10.4081/gh.2020.810] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 04/12/2020] [Indexed: 06/11/2023]
Abstract
The disordered urban growth that may favour the emergence of the Aedes aegypti mosquito in cities is a problem of increasing magnitude in middle- and high-income countries in the tropical part of the world. Currently, the World Health Organization (WHO) considers the control and elimination of Ae. aegypti a world-wide high priority as it is the main vector of many rapidly spreading viral diseases, dengue in particular. A major difficulty in controlling the proliferation of this vector is associated with identification of the breeding sites. The use of Unmanned Aerial Vehicles (UAVs) can be an efficient alternative to manual search because of high mobility and the ability to overcome physical obstacles, particularly in urban areas where it can offer close-up images of potential breeding sites that are difficult to reach. The objective of this study was to find a way to select the most suitable UAV for the identification of Ae. aegypti habitats by providing images of potential mosquito breeding sites. This can be accomplished by a Multiple-Criteria Decision Method (MCDM) based on an Analytical Hierarchy Process (AHP) for the evaluation of weights of the criteria used for characterizing UAVs. The alternatives were analyzed and ranked using the Fuzzy Set Theory (FST) merged with the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The methodology is explained and discussed with respect to identification and selection of the most appropriate UAV for aerial mapping of Aedes breeding sites.
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Affiliation(s)
| | | | | | | | - Aldo Braghini Junior
- Department of Industrial Engineering, Federal University of Technology (UTFPR), Paraná.
| | - João Carlos Colmenero
- Department of Industrial Engineering, Federal University of Technology (UTFPR), Paraná.
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Wang JN, Hou J, Zhong JY, Cao GP, Yu ZY, Wu YY, Li TQ, Liu QM, Gong ZY. Relationships between traditional larval indices and meteorological factors with the adult density of Aedes albopictus captured by BG-mosquito trap. PLoS One 2020; 15:e0234555. [PMID: 32525905 PMCID: PMC7289416 DOI: 10.1371/journal.pone.0234555] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 05/28/2020] [Indexed: 12/02/2022] Open
Abstract
Objectives Larval indices have been used for Ae. albopictus surveillance for many years, while there is limited use in assessing dengue transmission risk and adult mosquito emergence. This study is aimed to explore the relationships between larval indices and the Ae. albopictus density captured by BG-mosquito trap (BG-trap) method, with considering the meteorological factors. Methods Data on larval density, adult mosquito density and meteorology factors were collected in an entomological survey carried out in Quzhou City, Zhejiang Province of China in 2018. The Spearman’s rank correlation and Pearson correlation were used for the analysis on the correlation of density indices. Generalized additive models were established to analyze the influencing factors of mosquito density. Results Breteau index (BI), House index (HI) and Container index (CI) were highly correlated with each other (r>0.7, p<0.05). The Ae. albopictus density was significantly correlated with CI (rs = 0.260, p<0.05), CI pre one week (rs = 0.259, p<0.05), and CI pre three weeks (rs = 0.329, p<0.05). BI was correlated with female Ae. albopictus density pre 4 weeks (r = -0.299, p<0.05). Female Ae. albopictus density was correlated with CI pre 3 weeks (rs = 0.303, p<0.05). The influencing factors of BI were average wind speed pre 1 week, average temperature and female Ae. albopictus density pre 4 weeks. The influencing factors of CI were average humidity pre 3 weeks and average temperature. The influencing factors of HI were average temperature and precipitation pre 4 weeks. The influencing factor of Ae. albopictus density and female Ae. albopictus density was temperature. Conclusions The adult Ae. albopictus density had low correlation with certain larval indices. Some of the meteorology factors played significant roles in the density of adult Ae. albopictus and larva with or without a time lag.
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Affiliation(s)
- Jin-Na Wang
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Juan Hou
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Jian-Yue Zhong
- Quzhou Center for Disease Control and Prevention, Quzhou, China
| | - Guo-Ping Cao
- Quzhou Center for Disease Control and Prevention, Quzhou, China
| | - Zhang-You Yu
- Quzhou Center for Disease Control and Prevention, Quzhou, China
| | - Yu-Yan Wu
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Tian-Qi Li
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Qin-Mei Liu
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Zhen-Yu Gong
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
- * E-mail:
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Hustedt JC, Boyce R, Bradley J, Hii J, Alexander N. Use of pyriproxyfen in control of Aedes mosquitoes: A systematic review. PLoS Negl Trop Dis 2020; 14:e0008205. [PMID: 32530915 PMCID: PMC7314096 DOI: 10.1371/journal.pntd.0008205] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 06/24/2020] [Accepted: 03/10/2020] [Indexed: 01/11/2023] Open
Abstract
Dengue is the most rapidly spreading arboviral disease in the world. The current lack of fully protective vaccines and clinical therapeutics creates an urgent need to identify more effective means of controlling Aedes mosquitos, principally Aedes aegypti, as the main vector of dengue. Pyriproxyfen (PPF) is an increasingly used hormone analogue that prevents juvenile Aedes mosquitoes from becoming adults and being incapable of transmitting dengue. The objectives of the review were to (1) Determine the effect of PPF on endpoints including percentage inhibition of emergence to adulthood, larval mortality, and resistance ratios; and (2) Determine the different uses, strengths, and limitations of PPF in control of Aedes. A systematic search was applied to Pubmed, EMBASE, Web of Science, LILACS, Global Health, and the Cochrane database of Systematic Reviews. Out of 1,369 records, 90 studies met the inclusion criteria. Nearly all fit in one of the following four categories 1) Efficacy of granules, 2) Auto-dissemination/horizontal transfer, 3) use of ultra-low volume thermal fogging (ULV), thermal fogging (TF), or fumigant technologies, and 4) assessing mosquito resistance. PPF granules had consistently efficacious results of 90-100% inhibition of emergence for up to 90 days. The evidence is less robust but promising regarding PPF dust for auto-dissemination and the use of PPF in ULV, TF and fumigants. Several studies also found that while mosquito populations were still susceptible to PPF, the lethal concentrations increased among temephos-resistant mosquitoes compared to reference strains. The evidence is strong that PPF does increase immature mortality and adult inhibition in settings represented in the included studies, however future research should focus on areas where there is less evidence (e.g. auto-dissemination, sprays) and new use cases for PPF. A better understanding of the biological mechanisms of cross-resistance between PPF, temephos, and other insecticides will allow control programs to make better informed decisions.
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Affiliation(s)
- John Christian Hustedt
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Epidemiology Department, Malaria Consortium, London, United Kingdom
| | - Ross Boyce
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - John Bradley
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jeffrey Hii
- Epidemiology Department, Malaria Consortium, London, United Kingdom
| | - Neal Alexander
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Bibi R, Tariq RM, Rasheed M. Toxic assessment, growth disrupting and neurotoxic effects of red seaweeds' botanicals against the dengue vector mosquito Aedes aegypti L. Ecotoxicol Environ Saf 2020; 195:110451. [PMID: 32199214 DOI: 10.1016/j.ecoenv.2020.110451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 03/04/2020] [Accepted: 03/06/2020] [Indexed: 06/10/2023]
Abstract
Application of synthetic pesticides over decades to control insects, pests, and disease vectors has resulted in negative impacts on environment and health. The current study assessed the toxicological effects of 12 botanicals obtained from 4 different red seaweeds against the dengue vector mosquito Aedes aegypti L. (Diptera: Culicidae). Four species of red seaweeds, namely Laurencia karachiana, Gracilaria foliifera, Jania rubens, Asparagopsis taxiformis, were collected from Karachi coast and extracted with hexane, dichloromethane and methanol. The efficiency of these extracts was determined by using a dose-response bioassay method against 4th instar larvae of Ae. aegypti. Separate investigations on the toxicity and IGI effects were done. Comparative studies showed that the hexane extracts induced more toxic effects. Based on the LC50 values, obtained after 24 h of treatments, hexane extract of J. rubens (HJ) exhibited toxic effects with LC50 32 μg/mL, (equivalent to GHS category 3), followed by G. foliifera (HG) (LC50 76.8 μg/mL). HJ also showed prominent neurotoxic effects within 1-6 h. Comparatively, higher morphological abnormalities and growth inhibiting (IGI) effects were obtained in the dichloromethane and methanol extracts treated larvae, after 48-96 h, resulting in the formation of immature life forms such as larvi-pupae and pupi-adult. Presumptive growth inhibiting effects were also noted. These included formation of albino and black pupae, deformities in the internal structure of the treated larvae and the chitin synthesis related effects such as 'inhibiting effect on adult emergence'. Finding revealed that red seaweeds, harvested from the Arabian Sea, have potentials to affect Ae. aegypti survival and thus can be utilized as green pesticides.
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Affiliation(s)
- Rabia Bibi
- Centre of Excellence in Marine Biology, University of Karachi, Karachi, 75270, Pakistan.
| | | | - Munawwer Rasheed
- Centre of Excellence in Marine Biology, University of Karachi, Karachi, 75270, Pakistan; Department of Chemistry, University of Karachi, Karachi, 75270, Pakistan.
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Durand B, Lo Modou M, Tran A, Ba A, Sow F, Belkhiria J, Fall AG, Biteye B, Grosbois V, Chevalier V. Rift Valley fever in northern Senegal: A modelling approach to analyse the processes underlying virus circulation recurrence. PLoS Negl Trop Dis 2020; 14:e0008009. [PMID: 32479505 PMCID: PMC7289439 DOI: 10.1371/journal.pntd.0008009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 06/11/2020] [Accepted: 04/22/2020] [Indexed: 01/12/2023] Open
Abstract
Rift Valley fever (RVF) is endemic in northern Senegal, a Sahelian area characterized by a temporary pond network that drive both RVF mosquito population dynamics and nomadic herd movements. To investigate the mechanisms that explain RVF recurrent circulation, we modelled a realistic epidemiological system at the pond level integrating vector population dynamics, resident and nomadic ruminant herd population dynamics, and nomadic herd movements recorded in Younoufere area. To calibrate the model, serological surveys were performed in 2015–2016 on both resident and nomadic domestic herds in the same area. Mosquito population dynamics were obtained from a published model trained in the same region. Model comparison techniques were used to compare five different scenarios of virus introduction by nomadic herds associated or not with vertical transmission in Aedes vexans. Our serological results confirmed a long lasting RVF endemicity in resident herds (IgG seroprevalence rate of 15.3%, n = 222), and provided the first estimation of RVF IgG seroprevalence in nomadic herds in West Africa (12.4%, n = 660). Multivariate analysis of serological data suggested an amplification of the transmission cycle during the rainy season with a peak of circulation at the end of that season. The best scenario of virus introduction combined yearly introductions of RVFV from 2008 to 2015 (the study period) by nomadic herds, with a proportion of viraemic individuals predicted to be larger in animals arriving during the 2nd half of the rainy season (3.4%). This result is coherent with the IgM prevalence rate (4%) found in nomadic herds sampled during the 2nd half of the rainy season. Although the existence of a vertical transmission mechanism in Aedes cannot be ruled out, our model demonstrates that nomadic movements are sufficient to account for this endemic circulation in northern Senegal. Rift Valley fever (RVF) is one of the most important vector borne disease in Africa, seriously affecting the health of domestic ruminants and humans and leading to severe economic consequences. This disease is endemic in northern Senegal, a Sahelian area characterized by a temporary pond network that drive both RVF mosquito population dynamics and nomadic herd movements. Two non-exclusive mechanisms may support this endemicity: recurrent introductions of the virus by nomadic animals, and vertical transmission of the virus (i.e. from infected female mosquito to eggs) in local Aedes populations. The authors followed resident and nomadic domestic herds for 1 year. They used the data thus obtained to model a realistic epidemiological system at the pond level integrating vector population dynamics, resident and nomadic ruminant herd population dynamics. They found that the best scenario explaining RVF remanence combined yearly introductions of RVFV by nomadic herds, with a viraemic proportion predicted to be larger in animals arriving during the 2nd half of the rainy season, which is consistent with an amplification of virus circulation in the area during the rainy season. Although the existence of a vertical transmission mechanism in Aedes cannot be ruled out, their results demonstrates that nomadic movements are sufficient to account for this endemic circulation in northern Senegal.
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Affiliation(s)
- Benoit Durand
- Epidemiology Unit, Laboratory for Animal Health, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), University Paris-Est, Maisons-Alfort, France
- * E-mail: (BD); (VC)
| | | | - Annelise Tran
- CIRAD, UMR TETIS, Sainte-Clotilde, Réunion, France
- CIRAD, UMR ASTRE, Montpellier, France
- Université Montpellier, Montpellier, France
| | - Aminata Ba
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | - Fafa Sow
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | - Jaber Belkhiria
- Center for Animal Disease Modeling and Surveillance, Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, California, United States of America
| | | | - Biram Biteye
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | | | - Véronique Chevalier
- CIRAD, UMR ASTRE, Montpellier, France
- CIRAD, UMR ASTRE, Phnom Penh, Cambodia
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
- * E-mail: (BD); (VC)
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Qing W, Zhijing X, Guangfu Y, Fengxia M, Qiyong L, Zhong Z, Ruiling Z. Variation in the microbiota across different developmental stages of Aedes albopictus is affected by ampicillin exposure. Microbiologyopen 2020; 9:1162-1174. [PMID: 32207564 PMCID: PMC7294303 DOI: 10.1002/mbo3.1026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 02/14/2020] [Accepted: 02/15/2020] [Indexed: 12/23/2022] Open
Abstract
The microbiota plays an important role in the growth of mosquitoes and the transmission of mosquito-borne pathogens. The effects of changes in aquatic habitats in which mosquitoes live, as one of the major factors closely associated with the microbial communities of mosquitoes, on the microbiota of different developmental stages remain to be elucidated. Here, we compared the microbiota of larvae and pupae of Aedes albopictus exposed to different ampicillin concentrations and investigated the bacterial composition of adult females. The results demonstrate that the microbial community differed substantially between developmental stages and that samples of the same stages shared similarities, whereas differences were observed between adult females. Based on all observations, we hypothesize that the use of ampicillin caused dysbiosis rather than excluding bacteria from mosquitoes and that the disturbing effect of ampicillin was obvious in adults. Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that most of the bacteria identified in this study were significantly associated with metabolism. Taken together, our results indicate that ampicillin can change the abundance of bacteria, while microbial communities of Ae. albopictus showed obvious stage-specific characteristics. Further investigations are needed to characterize specific bacterial components that are affected by ampicillin exposure and to quantify their functions, thereby providing a better understanding of the influence of antibiotics on microbial communities at different life stages.
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Affiliation(s)
- Wan Qing
- School of Basic Medical ScienceShandong First Medical UniversityTaianChina
| | - Xue Zhijing
- State Key Laboratory of Infectious Disease Prevention and ControlNational Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijingChina
| | - Yu Guangfu
- School of Basic Medical ScienceShandong First Medical UniversityTaianChina
| | - Meng Fengxia
- State Key Laboratory of Infectious Disease Prevention and ControlNational Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijingChina
| | - Liu Qiyong
- State Key Laboratory of Infectious Disease Prevention and ControlNational Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijingChina
| | - Zhang Zhong
- School of Basic Medical ScienceShandong First Medical UniversityTaianChina
| | - Zhang Ruiling
- School of Basic Medical ScienceShandong First Medical UniversityTaianChina
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72
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Benitez EM, Ludueña-Almeida F, Frías-Céspedes M, Almirón WR, Estallo EL. Could land cover influence Aedes aegypti mosquito populations? Med Vet Entomol 2020; 34:138-144. [PMID: 31840284 DOI: 10.1111/mve.12422] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 10/02/2019] [Accepted: 11/15/2019] [Indexed: 06/10/2023]
Abstract
Aedes aegypti is mainly found in urban environments, where human activity guarantees the permanent availability of potential larval habitats. The present study aimed to test for a possible association between Ae. aegypti infestation and land cover classes. From 23 February to 22 May 2015, immature mosquitoes (except eggs) were sampled in artificial containers identified in dwellings in Córdoba city, Argentina. The proportion of each land cover class was determined by SPOT-5 (Satellites Pour 1'Observation de la Terre or Earth-observing Satellites) image classification. Generalized linear models were developed to assess a suite of predetermined hypotheses and identified cover class variables associated with Ae. aegypti infestation. Arboreal vegetation was identified as the land cover with the greatest relative importance, negatively associated with Ae. aegypti mosquitoes. More infestation was find in areas with less arboreal vegetation, which corresponds to more urbanized areas.
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Affiliation(s)
- E M Benitez
- Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT) CONICET- Universidad Nacional de Córdoba. Centro de Investigaciones Entomológicas de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - F Ludueña-Almeida
- Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT) CONICET- Universidad Nacional de Córdoba. Centro de Investigaciones Entomológicas de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
- Cátedra de Matemática (Cs. Biológicas). Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - M Frías-Céspedes
- Ministerio de Salud de la Provincia de Córdoba- Dirección de Epidemiología, Córdoba, Argentina
| | - W R Almirón
- Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT) CONICET- Universidad Nacional de Córdoba. Centro de Investigaciones Entomológicas de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - E L Estallo
- Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT) CONICET- Universidad Nacional de Córdoba. Centro de Investigaciones Entomológicas de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
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Calvez E, Pocquet N, Malau A, Kilama S, Taugamoa A, Labrousse D, Boussès P, Failloux AB, Dupont-Rouzeyrol M, Mathieu-Daudé F. Assessing entomological risk factors for arboviral disease transmission in the French Territory of the Wallis and Futuna Islands. PLoS Negl Trop Dis 2020; 14:e0008250. [PMID: 32401756 PMCID: PMC7219742 DOI: 10.1371/journal.pntd.0008250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 03/24/2020] [Indexed: 11/21/2022] Open
Abstract
Background The French overseas Territory of the Wallis and Futuna Islands has been affected by several dengue epidemics. Aedes polynesiensis is the main mosquito vector described in this territory. Other Aedes species have been reported, but recent entomological data are missing to infer the presence of other potential arbovirus vectors and to assess the entomological risk factors for transmission of arboviral diseases. Methodology/ Principal findings An entomological prospective study was conducted on the three main islands of the territory to determine the presence and distribution of Aedes spp. Larvae, pupae and adult mosquitoes were collected from 54 sampling points in different environments, with a final sampling of 3747 immature stages and 606 adults. The main identified breeding sites were described. Ae. polynesiensis was found in every sampled site in peridomestic and wild habitats. Ae. aegypti was only found on the island of Wallis in peridomestic environments with a limited distribution. Two other Aedes species endemic to the Pacific were recorded, Aedes oceanicus and Aedes futunae. To evaluate the ability of local Ae. polynesiensis to transmit the chikungunya virus (CHIKV), two field populations were analyzed for vector competence using experimental oral exposure of females to CHIKV and infection, dissemination and transmission assays. Results showed that both populations of Ae. polynesiensis were competent for CHIKV (30% at 7 days post-infection). Conclusions/Significance This study showed the ubiquitous distribution and abundance of Ae. polynesiensis on the three islands and demonstrated that local populations were able to transmit CHIKV. Combined with the presence and expansion of Ae. aegypti on the main island of Wallis, these data highlight the risk of transmission of arboviral diseases in the territory of Wallis and Futuna and provide relevant information for entomological surveillance and vector control programs. The French overseas Territory of the Wallis and Futuna Islands, located in the South Pacific, has been affected by several dengue epidemics, but did not face Zika or chikungunya outbreaks, unlike other neighboring islands. The near-exclusive presence of the Aedes polynesiensis mosquito in the islands of Wallis and Futuna confirmed the role played by this mosquito as a vector of dengue fever. A local Ae. polynesiensis population was recently shown to be able to transmit the Zika virus under experimental conditions, but its susceptibility to the chikungunya virus was still unknown, and recent data on the presence of other potential arbovirus vectors were missing. Therefore, we investigated the entomological risk factors for the transmission of arboviral diseases in the Wallis and Futuna Islands. We reported the occurrence and distribution of different Aedes species, especially the abundant presence of Ae. polynesiensis across the territory and the spread of Ae. aegypti in the island of Wallis. Our results demonstrated the ability of local Ae. polynesiensis populations to transmit the chikungunya virus. These findings highlight the risk of arbovirus transmission in the Wallis and Futuna Islands and provide relevant data to guide prevention and vector control strategies in the territory.
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Affiliation(s)
- Elodie Calvez
- URE-Dengue et autres Arboviroses, Institut Pasteur de Nouvelle-Calédonie, Réseau International Institut Pasteur, Nouméa, New Caledonia
| | - Nicolas Pocquet
- URE-Entomologie Médicale, Institut Pasteur de Nouvelle-Calédonie, Réseau International Institut Pasteur, Nouméa, New Caledonia
| | - Atoloto Malau
- Service de l’Environnement de Wallis et Futuna, Mata’Utu, Uvea, Wallis and Futuna
| | - Sosiasi Kilama
- URE-Entomologie Médicale, Institut Pasteur de Nouvelle-Calédonie, Réseau International Institut Pasteur, Nouméa, New Caledonia
| | - Alefosio Taugamoa
- Service de l’Environnement de Wallis et Futuna, Leava, Futuna, Wallis and Futuna
| | - Didier Labrousse
- Service de l’Environnement de Wallis et Futuna, Leava, Futuna, Wallis and Futuna
| | - Philippe Boussès
- UMR MIVEGEC Univ Montpellier, IRD, CNRS, Institut de Recherche pour le Développement, Montpellier, France
| | | | - Myrielle Dupont-Rouzeyrol
- URE-Dengue et autres Arboviroses, Institut Pasteur de Nouvelle-Calédonie, Réseau International Institut Pasteur, Nouméa, New Caledonia
| | - Françoise Mathieu-Daudé
- UMR MIVEGEC Univ Montpellier, IRD, CNRS, Institut de Recherche pour le Développement, Montpellier, France
- UMR MIVEGEC Univ Montpellier, IRD, CNRS, Institut de Recherche pour le Développement, Nouméa, New Caledonia
- * E-mail:
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Forsyth JE, Mutuku FM, Kibe L, Mwashee L, Bongo J, Egemba C, Ardoin NM, LaBeaud AD. Source reduction with a purpose: Mosquito ecology and community perspectives offer insights for improving household mosquito management in coastal Kenya. PLoS Negl Trop Dis 2020; 14:e0008239. [PMID: 32392226 PMCID: PMC7241847 DOI: 10.1371/journal.pntd.0008239] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 05/21/2020] [Accepted: 03/20/2020] [Indexed: 01/17/2023] Open
Abstract
Understanding mosquito breeding behavior as well as human perspectives and practices are crucial for designing interventions to control Aedes aegypti mosquito-borne diseases as these mosquitoes primarily breed in water-holding containers around people's homes. The objectives of this study were to identify productive mosquito breeding habitats in coastal Kenya and to understand household mosquito management behaviors and their behavioral determinants. The field team conducted entomological surveys in 444 households and semi-structured interviews with 35 female caregivers and 37 children in Kwale County, coastal Kenya, between May and December 2016. All potential mosquito habitats with or without water were located, abundances of mosquito immatures measured and their characteristics recorded. Interviews explored household mosquito management behaviors and their behavioral determinants. 2,452 container mosquito habitats were counted containing 1,077 larvae and 390 pupae, predominantly Aedes species. More than one-third of the positive containers were found outside houses in 1 of the 10 villages. Containers holding water with no intended purpose contained 55.2% of all immature mosquitoes. Containers filled with rainwater held 95.8% of all immature mosquitoes. Interviews indicated that households prioritize sleeping under bednets as a primary protection against mosquito-borne disease because of concern about night-time biting, malaria-transmitting Anopheles mosquitoes. Respondents had limited knowledge about the mosquito life cycle, especially with respect to day-time biting, container-breeding Aedes mosquitoes. Therefore, respondents did not prioritize source reduction. Most mosquitoes breed in containers that have no direct or immediate purpose ("no-purpose containers"). These containers may be left unattended for several days allowing rainwater to collect, and creating ideal conditions for mosquito breeding. An intervention that requires little effort and targets only the most productive containers could effectively reduce mosquito indices and, relatedly, mosquito-borne disease risk.
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Affiliation(s)
- Jenna E. Forsyth
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, California, United States of America
- * E-mail:
| | - Francis M. Mutuku
- Technical University of Mombasa, Mombasa, Kenya
- Vector-Borne Disease Unit, Msambweni County Referral Hospital, Msambweni, Kenya
| | - Lydiah Kibe
- Centre for Geographic Medicine Research Coast, Kenya Medical Research Institute, Kilifi, Kenya
| | - Luti Mwashee
- Technical University of Mombasa, Mombasa, Kenya
- Vector-Borne Disease Unit, Msambweni County Referral Hospital, Msambweni, Kenya
| | - Joyce Bongo
- Vector-Borne Disease Unit, Msambweni County Referral Hospital, Msambweni, Kenya
| | - Chika Egemba
- Stanford University School of Medicine, Stanford, California, United States of America
| | - Nicole M. Ardoin
- Emmett Interdisciplinary Program in Environment and Resources, Graduate School of Education, and Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - A. Desiree LaBeaud
- Stanford University School of Medicine, Stanford, California, United States of America
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Jourdain F, Roiz D, de Valk H, Noël H, L’Ambert G, Franke F, Paty MC, Guinard A, Desenclos JC, Roche B. From importation to autochthonous transmission: Drivers of chikungunya and dengue emergence in a temperate area. PLoS Negl Trop Dis 2020; 14:e0008320. [PMID: 32392224 PMCID: PMC7266344 DOI: 10.1371/journal.pntd.0008320] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 06/02/2020] [Accepted: 04/24/2020] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The global spread of Aedes albopictus has exposed new geographical areas to the risk of dengue and chikungunya virus transmission. Several autochthonous transmission events have occurred in recent decades in Southern Europe and many indicators suggest that it will become more frequent in this region in the future. Environmental, socioeconomic and climatic factors are generally considered to trigger the emergence of these viruses. Accordingly, a greater knowledge of the determinants of this emergence in a European context is necessary to develop adapted surveillance and control strategies, and public health interventions. METHODOLOGY/PRINCIPAL FINDINGS Using French surveillance data collected from between 2010 and 2018 in areas of Southern France where Ae. albopictus is already established, we assessed factors associated with the autochthonous transmission of dengue and chikungunya. Cases leading to autochthonous transmission were compared with those without subsequent transmission using binomial regression. We identified a long reporting delay (≥ 21 days) of imported cases to local health authorities as the main driver for autochthonous transmission of dengue and chikungunya in Southern France. The presence of wooded areas around the cases' place of residence and the accumulation of heat during the season also increased the risk of autochthonous arbovirus transmission. CONCLUSIONS Our findings could inform policy-makers when developing strategies to the emerging threats of dengue and chikungunya in Southern Europe and can be extrapolated in this area to other viruses such as Zika and yellow fever, which share the same vector. Furthermore, our results allow a more accurate characterization of the environments most at risk, and highlight the importance of implementing surveillance systems which ensure the timely reporting and of imported cases and swift interventions.
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Affiliation(s)
- Frédéric Jourdain
- Santé publique France (French National Public Health Agency), Saint-Maurice, France
- MIVEGEC Unit, IRD 224, CNRS 5290, Univ Montpellier, Montpellier, France
| | - David Roiz
- MIVEGEC Unit, IRD 224, CNRS 5290, Univ Montpellier, Montpellier, France
| | - Henriette de Valk
- Santé publique France (French National Public Health Agency), Saint-Maurice, France
| | - Harold Noël
- Santé publique France (French National Public Health Agency), Saint-Maurice, France
| | - Grégory L’Ambert
- Entente interdépartementale pour la démoustication du littoral méditerranéen (EID Méditerranée), Montpellier, France
| | - Florian Franke
- Santé publique France (French National Public Health Agency), Marseille, France
| | - Marie-Claire Paty
- Santé publique France (French National Public Health Agency), Saint-Maurice, France
| | - Anne Guinard
- Santé publique France (French National Public Health Agency), Toulouse, France
| | | | - Benjamin Roche
- MIVEGEC Unit, IRD 224, CNRS 5290, Univ Montpellier, Montpellier, France
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Dittmer J, Gabrieli P. Transstadial metabolic priming mediated by larval nutrition in female Aedes albopictus mosquitoes. J Insect Physiol 2020; 123:104053. [PMID: 32251651 DOI: 10.1016/j.jinsphys.2020.104053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
Mosquitoes are important vectors of human pathogens, which are transmitted by female mosquitoes via blood-feeding. Larval nutrition can have an important impact on the number of blood meals taken by adult females shortly after emergence, as nutritional deficiencies during the larval stage may result in pre-vitellogenic blood meals, which are not invested into egg development but into the endogenous nutrient reserves of the female. Here, we investigated the impact of nutrient deprivation during the larval stage on adult nutrient metabolism, longevity and blood-seeking behaviour in females of the invasive Asian tiger mosquito Aedes albopictus. We demonstrate that Ae. albopictus females are able to compensate for nutrient deprivation during the larval stage by increasing their development time until sufficient nutrients are acquired. Nonetheless, nutrient-poor larval conditions had a long-lasting priming effect on adult female metabolism, since these females accumulated lower nutrient reserves from carbohydrates and survived longer compared to females reared in nutrient-rich larval conditions. Moreover, nutrient and ATP levels of females from nutrient-poor larval conditions remained stable over a longer timespan without access to additional carbohydrates. This suggests differences in adult female metabolism in response to larval nutrition, with potential impact on the vectorial capacity of female mosquitoes.
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Affiliation(s)
- Jessica Dittmer
- Department of Biology & Biotechnology, Università degli Studi di Pavia, Via Ferrata 9, 27100 Pavia, Italy.
| | - Paolo Gabrieli
- Department of Biology & Biotechnology, Università degli Studi di Pavia, Via Ferrata 9, 27100 Pavia, Italy.
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Carvajal TM, Ogishi K, Yaegeshi S, Hernandez LFT, Viacrusis KM, Ho HT, Amalin DM, Watanabe K. Fine-scale population genetic structure of dengue mosquito vector, Aedes aegypti, in Metropolitan Manila, Philippines. PLoS Negl Trop Dis 2020; 14:e0008279. [PMID: 32365059 PMCID: PMC7224578 DOI: 10.1371/journal.pntd.0008279] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/14/2020] [Accepted: 04/08/2020] [Indexed: 11/25/2022] Open
Abstract
Dengue is a highly endemic disease in Southeast Asia and is transmitted primarily by the mosquito, Aedes aegypti. The National Capital Region (NCR) of the Philippines, or Metropolitan Manila, is a highly urbanized area that is greatly affected by this arboviral disease. Urbanization has been shown to increase the dispersal of this mosquito vector. For this reason, we conducted a fine-scale population genetic study of Ae. aegypti in this region. We collected adult Ae. aegypti mosquitoes (n = 526 individuals) within the region (n = 21 study areas) and characterized the present population structure and the genetic relatedness among mosquito populations. We genotyped 11 microsatellite loci from all sampled mosquito individuals and analyzed their genetic diversity, differentiation and structure. The results revealed low genetic differentiation across mosquito populations which suggest high gene flow and/or weak genetic drift among mosquito populations. Bayesian analysis indicated multiple genetic structures (K = 3-6), with no clear genetically distinct population structures. This result implies the passive or long-distance dispersal capability nature Ae. aegypti possibly through human-mediated transportation. The constructed dendrogram in this study describes the potential passive dispersal patterns across Metropolitan Manila. Furthermore, spatial autocorrelation analysis showed the limited and active dispersal capability (<1km) of the mosquito vector. Our findings are consistent with previous studies that investigated the genetic structure and dual (active and passive) dispersal capability of Ae. aegypti in a fine-scale highly urbanized area.
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Affiliation(s)
- Thaddeus M. Carvajal
- Center for Marine Environmental Studies (CMES)–Ehime University, Matsuyama, Japan
- Department of Civil and Environmental Engineering—Ehime University, Matsuyama, Japan
- Biology Department–De La Salle University, Taft Ave Manila, Philippines
- Biological Control Research Unit, Center for Natural Science and Environmental Research—De La Salle University, Taft Ave Manila, Philippines
| | - Kohei Ogishi
- Department of Civil and Environmental Engineering—Ehime University, Matsuyama, Japan
| | - Sakiko Yaegeshi
- Department of Civil and Environmental Engineering—Ehime University, Matsuyama, Japan
- Department of Civil and Environmental Engineering, University of Yamanashi, Kofu, Japan
| | | | | | - Howell T. Ho
- Department of Biological Sciences, Trinity University of Asia, Quezon City, Philippines
| | - Divina M. Amalin
- Biology Department–De La Salle University, Taft Ave Manila, Philippines
- Biological Control Research Unit, Center for Natural Science and Environmental Research—De La Salle University, Taft Ave Manila, Philippines
| | - Kozo Watanabe
- Center for Marine Environmental Studies (CMES)–Ehime University, Matsuyama, Japan
- Department of Civil and Environmental Engineering—Ehime University, Matsuyama, Japan
- Biology Department–De La Salle University, Taft Ave Manila, Philippines
- Biological Control Research Unit, Center for Natural Science and Environmental Research—De La Salle University, Taft Ave Manila, Philippines
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Rajarethinam J, Ong J, Neo ZW, Ng LC, Aik J. Distribution and seasonal fluctuations of Ae. aegypti and Ae. albopictus larval and pupae in residential areas in an urban landscape. PLoS Negl Trop Dis 2020; 14:e0008209. [PMID: 32310960 PMCID: PMC7192508 DOI: 10.1371/journal.pntd.0008209] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 04/30/2020] [Accepted: 03/11/2020] [Indexed: 01/21/2023] Open
Abstract
Dengue, a vector-borne disease spread by Aedes mosquitoes, is a global threat. In the absence of an efficacious dengue vaccine, vector control is the key intervention tool in Singapore. A good understanding of vector habitats is essential to formulate operational strategies. We examined the distribution, long-term trend and seasonality of Aedes data collected during regulatory inspections in residences and public areas from 2008 to 2017. We also studied the seasonality of climate factors to understand their influence on the detection of Aedes-positive containers. The most frequently reported Aedes-positive containers were domestic containers, drains, discarded receptacles, ornamental containers, flower pot plates/trays, plants, gully traps, canvas/plastic sheet, bins, ground puddle, inspection chambers and roof tops/gutters. We found more Ae. aegypti and Ae. albopictus-positive containers per inspection in residences and public areas, respectively. The seasonality of Ae. aegypti-positive containers in residences and public areas coincided with that of mean temperature. However, the seasonality of Ae. albopictus-positive containers lagged by one month compared to that of mean temperature. Our study demonstrates the seasonal fluctuations of Aedes-positive containers in an urban environment. Understanding the distribution and seasonality of Aedes breeding helps to facilitate resource planning and community awareness to moderate dengue transmission.
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Affiliation(s)
| | - Janet Ong
- Environmental Health Institute, National Environment Agency, Singapore, Singapore
| | - Zhi-Wei Neo
- Environmental Public Health Operations, National Environment Agency, Singapore, Singapore
| | - Lee-Ching Ng
- Environmental Health Institute, National Environment Agency, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore
- * E-mail:
| | - Joel Aik
- Environmental Health Institute, National Environment Agency, Singapore, Singapore
- School of Public Health and Community Medicine, Faculty of Medicine, University of New South Wales, Level 3, Samuels Building, Botany Road, Keningston, New South Wales, Australia
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Marti GA, Bonica MB, Susevich ML, Reynaldi F, Micieli MV, Echeverría MG. Host range of Triatoma virus does not extend to Aedes aegypti and Apis mellifera. J Invertebr Pathol 2020; 173:107383. [PMID: 32298695 DOI: 10.1016/j.jip.2020.107383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 11/30/2022]
Abstract
Vector control is the most effective method to prevent transmission of Chagas disease. Control is mostly made through chemical insecticides although they have negative impact on wild pollinators, such as bees. Reducing pesticide use through biological alternatives could minimize the damage to these beneficial insects. Triatoma virus (TrV) is a pathogen able to kill triatomines and thus a valid candidate to be used as biological control agent. In this study we evaluate the capacity of TrV to infect an important beneficial insect (Apis mellifera) as well as a plague insect (Aedes aegypti). Results indicate that TrV does not infect the bees or mosquitoes tested in this study. The possible specificity of TrV for kissing bugs reinforces the possible use of TrV as a biological control agent for triatomines.
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Affiliation(s)
- Gerardo Aníbal Marti
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE-CCT-La Plata-CONICET-UNLP), Boulevard 120 s/n e/60 y 64, 1900 La Plata, Argentina.
| | - Melisa Berenice Bonica
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE-CCT-La Plata-CONICET-UNLP), Boulevard 120 s/n e/60 y 64, 1900 La Plata, Argentina
| | - María Laura Susevich
- Cátedra de Virología, Facultad de Ciencias Veterinarias (UNLP), 60 y 118, 1900 La Plata, Argentina; CCT-La Plata - CONICET, 8 #1467, 1900 La Plata, Argentina
| | - Francisco Reynaldi
- Cátedra de Virología, Facultad de Ciencias Veterinarias (UNLP), 60 y 118, 1900 La Plata, Argentina; CCT-La Plata - CONICET, 8 #1467, 1900 La Plata, Argentina
| | - María Victoria Micieli
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE-CCT-La Plata-CONICET-UNLP), Boulevard 120 s/n e/60 y 64, 1900 La Plata, Argentina
| | - María Gabriela Echeverría
- Cátedra de Virología, Facultad de Ciencias Veterinarias (UNLP), 60 y 118, 1900 La Plata, Argentina; CCT-La Plata - CONICET, 8 #1467, 1900 La Plata, Argentina
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Anaya P, Onofre J, Torres-Quintero MC, Sánchez J, Gill SS, Bravo A, Soberón M. Oligomerization is a key step for Bacillus thuringiensis Cyt1Aa insecticidal activity but not for toxicity against red blood cells. Insect Biochem Mol Biol 2020; 119:103317. [PMID: 31978588 PMCID: PMC7245338 DOI: 10.1016/j.ibmb.2020.103317] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/08/2020] [Accepted: 01/10/2020] [Indexed: 06/10/2023]
Abstract
Bacillus thuringiensis (Bt) Cyt1Aa toxin shows toxicity to mosquitoes, to certain coleopteran pests and also to red blood cells (RBC). However, its mode of action in the different target cells is not well defined. This protein is a single α-β domain pore-forming toxin, where a β sheet is wrapped by two α-helices layers. The Cyt1Aa α-helix hairpin in the N-terminal has been proposed to be involved in initial membrane binding and oligomerization, while the β sheet inserts into the membrane to form a pore that lyze the cells. To determine the role of the N-terminal α-helix hairpin region of Cyt1Aa in its mode of action, we characterized different single point mutations located in helices α-1 and α-2. Eight cysteine substitutions in different residues were produced in Bt, and we found that three of them: Cyt1AaA65C, Cyt1AaL85C and Cyt1AaN89C, lost insecticidal toxicity against Aedes aegypti larvae but retained similar or increased hemolytic activity towards rabbit RBC. Analysis of toxin binding and oligomerization using Ae. aegypti midgut brush border membrane vesicles showed that the three Cyt1Aa mutants non-toxic to Ae. aegypti were affected in oligomerization. However, these mutants were still hemolytic. Our data shows that oligomerization of Cyt1Aa toxin is essential for its toxicity to Ae. aegypti but not for its toxicity against RBC indicating that the mode of action of Cyt1Aa is different in these distinct target membranes.
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Affiliation(s)
- Paulina Anaya
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico
| | - Janette Onofre
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico
| | - Mary Carmen Torres-Quintero
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico
| | - Jorge Sánchez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico
| | - Sarjeet S Gill
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Alejandra Bravo
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico
| | - Mario Soberón
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico.
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Yang D, He Y, Ni W, Lai Q, Yang Y, Xie J, Zhu T, Zhou G, Zheng X. Semi-field life-table studies of Aedes albopictus (Diptera: Culicidae) in Guangzhou, China. PLoS One 2020; 15:e0229829. [PMID: 32187227 PMCID: PMC7080243 DOI: 10.1371/journal.pone.0229829] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 02/16/2020] [Indexed: 01/08/2023] Open
Abstract
Background Aedes albopictus is a major vector for several tropical infectious diseases. Characterization of Ae. albopictus development under natural conditions is crucial for monitoring vector population expansion, dengue virus transmission, and disease outbreak preparedness. Methods This study employed mosquito traits as a proxy to understanding life-table traits in mosquitoes using a semi–field study. Ae. albopictus larval and adult life-table experiments were conducted using microcosms under semi-field conditions in Guangzhou. Stage-specific development times and survivorship rates were determined and compared under semi-field conditions in different seasons from early summer (June) to winter (January), to determine the lower temperature limit for larval development and adult survivorship and reproductivity. Results The average egg- hatching rate was 60.1%, with the highest recorded in October (77.1%; mid-autumn). The larval development time was on average 13.2 days (range, 8.5–24.1 days), with the shortest time observed in September(8.7 days; early autumn) and longest in November (22.8 days). The pupation rates of Ae. albopictus larvae were on average 88.9% (range, 81.6–93.4%); they were stable from June to September but decreased from October to November. The adult emergence rates were on average 82.5% (range, 76.8–87.9%) and decreased from July to November. The median survival time of Ae. albopictus adults was on average 7.4 (range, 4.5–9.8), with the shortest time recorded in September. The average lifetime egg mass under semi-field conditions was 37.84 eggs/female. The larvae could develop into adults at temperatures as low as 12.3°C, and the adults could survive for 30.0 days at 16.3°C and still produce eggs. Overall, correlation analysis found that mean temperature and relative humidity were variables significantly affecting larval development and adult survivorship. Conclusion Ae. albopictus larvae could develop and emerge and the adults could survive and produce eggs in early winter in Guangzhou. The major impact of changes in ambient temperature, relative humidity, and light intensity was on the egg hatching rates, adult survival time, and egg mass production, rather than on pupation or adult emergence rates.
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Affiliation(s)
- Dizi Yang
- Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Yulan He
- Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Weigui Ni
- Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Qi Lai
- Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Yonghong Yang
- Nutritional Department, PLA Air Force Hospital of Southern Theater Command, Guangzhou, China
| | - Jiayan Xie
- Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Tianrenzheng Zhu
- Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Guofa Zhou
- Program in Public Health, University of California, Irvine, CA, United States of America
| | - Xueli Zheng
- Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, China
- * E-mail:
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Vera-Maloof FZ, Saavedra-Rodriguez K, Penilla-Navarro RP, D. Rodriguez-Ramirez A, Dzul F, Manrique-Saide P, Black WC. Loss of pyrethroid resistance in newly established laboratory colonies of Aedes aegypti. PLoS Negl Trop Dis 2020; 14:e0007753. [PMID: 32176693 PMCID: PMC7117762 DOI: 10.1371/journal.pntd.0007753] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 04/02/2020] [Accepted: 01/25/2020] [Indexed: 12/04/2022] Open
Abstract
Background Resistance to pyrethroid insecticides in Aedes aegypti has become widespread after almost two decades of the frequent use of these pesticides to reduce arbovirus transmission. Despite this resistance, pyrethroids continue to be used because they are relatively inexpensive and have low human toxicity. Resistance management has been proposed as a way to retain the use of pyrethroids in natural populations. A key component of resistance management is the assumption that negative fitness is associated with resistance alleles such that resistance alleles will decline in frequency when the insecticides are removed. At least three studies in Ae. aegypti have demonstrated a decrease in pyrethroid resistance once the insecticide has been removed. Methods/Principal findings The present study aims to evaluate variation in the loss of pyrethroid resistance among newly established laboratory populations of Ae. aegypti from Mexico. Eight field collections were maintained for up to eight generations, and we recorded changes in the frequencies of the mutations at the V1,016I locus and at the F1,534C locus in the voltage-gated sodium channel gene (VGSC). I1,016 and C1,534 confer resistance. We also examined resistance ratios (RR) with type 1 and 2 pyrethroids. Conclusions/Significance We demonstrate that, in general, the frequency of the Ae. aegypti pyrethroid-resistance alleles I1,016 and C1,534 decline when they are freed from pyrethroid pressure in the laboratory. However, the pattern of decline is strain dependent. In agreement with earlier studies, the RR was positively correlated with the frequencies of the resistance allele I1,016 and showed significant protection against permethrin, and deltamethrin, whereas F1,534C showed protection against permethrin but not against deltamethrin. The author is interested in the evolution of genes that confer resistance to insecticides, especially when this evolution affects the binding of insecticides to their target sites. The Voltage-Gated Sodium Channel gene provides an excellent opportunity to understand how mutations at the target site(s) affect the evolution of resistance in many different pest insect species, including Aedes aegypti, which is the primary vector of the dengue, yellow fever, Zika and chikungunya viruses.
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Affiliation(s)
- Farah Z. Vera-Maloof
- Colorado State University, College of Veterinary Medicine and Biomedical Sciences, Department of Microbiology, Immunology and Pathology, Arthropod Borne and Infectious Diseases Laboratory, Campus Delivery, Fort Collins, Colorado, United States of America
| | - Karla Saavedra-Rodriguez
- Colorado State University, College of Veterinary Medicine and Biomedical Sciences, Department of Microbiology, Immunology and Pathology, Arthropod Borne and Infectious Diseases Laboratory, Campus Delivery, Fort Collins, Colorado, United States of America
| | - Rosa P. Penilla-Navarro
- Centro Regional de Investigación en Salud Pública, Instituto Nacional de Salud Pública, Colonia Centro, Tapachula, Chiapas, México
| | - Americo D. Rodriguez-Ramirez
- Centro Regional de Investigación en Salud Pública, Instituto Nacional de Salud Pública, Colonia Centro, Tapachula, Chiapas, México
| | - Felipe Dzul
- Centro Nacional de Programas Preventivos y Control de Enfermedades, Benjamín Franklin, Escandón, Ciudad de México, México
| | - Pablo Manrique-Saide
- Universidad Autonoma de Yucatan, México, Parque Santa Lucia, Centro, Mérida, Yucatan, Mexico
| | - William C. Black
- Colorado State University, College of Veterinary Medicine and Biomedical Sciences, Department of Microbiology, Immunology and Pathology, Arthropod Borne and Infectious Diseases Laboratory, Campus Delivery, Fort Collins, Colorado, United States of America
- * E-mail:
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83
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Benedict MQ, Hunt CM, Vella MG, Gonzalez KM, Dotson EM, Collins CM. Pragmatic selection of larval mosquito diets for insectary rearing of Anopheles gambiae and Aedes aegypti. PLoS One 2020; 15:e0221838. [PMID: 32160192 PMCID: PMC7065774 DOI: 10.1371/journal.pone.0221838] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 02/06/2020] [Indexed: 11/18/2022] Open
Abstract
Larval mosquitoes are aquatic omnivorous scavengers which scrape food from submerged surfaces and collect suspended food particles with their mouth brushes. The composition of diets that have been used in insectaries varies widely though necessarily provides sufficient nutrition to allow colonies to be maintained. Issues such as cost, availability and experience influence which diet is selected. One component of larval diets, essential fatty acids, appears to be necessary for normal flight though deficiencies may not be evident in laboratory cages and are likely more important when mosquitoes are reared for release into the field in e.g. mark-release-recapture and genetic control activities. In this study, four diets were compared for rearing Anopheles gambiae and Aedes aegypti, all of which provide these essential fatty acids. Two diets were custom formulations specifically designed for mosquitoes (Damiens) and two were commercially available fish foods: Doctors Foster and Smith Koi Staple Diet and TetraMin Plus Flakes. Development rate, survival, dry weight and adult longevity of mosquitoes reared with these four diets were measured. The method of presentation of one diet, Koi pellets, was additionally fed in two forms, pellets or a slurry, to determine any effect of food presentation on survival and development rate. While various criteria might be selected to choose ‘the best’ food, the readily-available Koi pellets resulted in development rates and adult longevity equal to the other diets, high survival to the adult stage and, additionally, this is available at low cost.
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Affiliation(s)
- Mark Q. Benedict
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Entomology Branch, Atlanta, Georgia, United States of America
- * E-mail:
| | - Catherine M. Hunt
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Entomology Branch, Atlanta, Georgia, United States of America
| | - Michael G. Vella
- Frontier Scientific Services, Newark, Delaware, United States of America
| | | | - Ellen M. Dotson
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Entomology Branch, Atlanta, Georgia, United States of America
| | - C. Matilda Collins
- Centre for Environmental Policy, Imperial College London, London, United Kingdom
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84
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Liu P, Jin B, Li X, Zhao Y, Gu J, Biedler JK, Tu ZJ, Chen XG. Nix is a male-determining factor in the Asian tiger mosquito Aedes albopictus. Insect Biochem Mol Biol 2020; 118:103311. [PMID: 31901476 DOI: 10.1016/j.ibmb.2019.103311] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 12/26/2019] [Accepted: 12/27/2019] [Indexed: 05/06/2023]
Abstract
The initial signal that governs sex determination is highly variable among insects. A homolog of Nix, the male-determining factor in Aedes aegypti, was previously found in the Asian tiger mosquito Ae. albopictus. Here we show that the Ae. albopictus Nix (AalNix) is more complex in gene structure and splice isoforms than its Ae. aegypti homolog (AaeNix). AalNix shows a similar transcription profile compared to AaeNix. CRISPR/Cas9-mediated knockouts of AalNix in vivo and in the Ae. albopictus C6/36 cells lead to a shift of dsx and fru splicing towards the female isoforms. G0 knockout males showed feminization and deformities including feminized antennae, absence or partial absence of gonocoxites, gonostyli, testes and accessory glands, and the formation of ovaries. Despite ~70 MY of divergence, Nix functions as a conserved male-determining factor in the two most important arboviral vectors, namely Ae. aegypti and Ae. albopictus.
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Affiliation(s)
- Peiwen Liu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Binbin Jin
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Xiaocong Li
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Yijie Zhao
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Jinbao Gu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - James K Biedler
- Department of Biochemistry and the Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Zhijian Jake Tu
- Department of Biochemistry and the Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Xiao-Guang Chen
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China.
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85
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Hirabayashi K, Nihei N, Kobayashi M, Tsuda Y, Sawabe K. Elevational Distribution of the Asian Tiger Mosquito, Aedes albopictus, in the Inland Mountain Area of Nagano and Yamanashi Prefectures, Japan. J Am Mosq Control Assoc 2020; 36:1-10. [PMID: 32497476 DOI: 10.2987/19-6902.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nagano and Yamanashi prefectures of Japan comprise an inland mountain area that extends widely north and south, with elevation varying greatly by location. Mosquitoes transmitting infectious disease have a diversity of habitats in Nagano and Yamanashi, and many species can be expected there. However, there have been few reports on mosquito fauna; in particular, little information is available on mosquitoes such as Aedes albopictus. The mosquito fauna was investigated to clarify their elevational distribution ranging from 317 to 1,534 m, focusing especially on Ae. albopictus, in 24 areas in Nagano and Yamanashi prefectures from July to September in 2012-16. Adult mosquitoes were collected using the Centers for Disease Control and Prevention traps in each area, in addition to larval mosquito collections at several temple and shrine precincts in each area. At sites where elevations were >800 m (14 sites), no adult Ae. albopictus were captured. In addition, larval Ae. albopictus were not collected at elevations >728 m (15 sites). Aedes albopictus was captured at 20 other sites (annual mean air temperature ranged from 9.4 to 15.2°C, July-September mean air temperature ranged from 19.9 to 25.0°C).
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86
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Giordano BV, Gasparotto A, Liang P, Nelder MP, Russell C, Hunter FF. Discovery of an Aedes (Stegomyia) albopictus population and first records of Aedes (Stegomyia) aegypti in Canada. Med Vet Entomol 2020; 34:10-16. [PMID: 31566765 DOI: 10.1111/mve.12408] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/15/2019] [Accepted: 08/28/2019] [Indexed: 06/10/2023]
Abstract
A population of Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae), a vector of chikungunya, dengue, yellow fever, and Zika and West Nile viruses, has been detected in Windsor, Ontario, Canada from 2016 onwards. Here, we describe its seasonal distribution, as well as the various aquatic habitats from which this species was collected and its larval co-habitation. We collected immatures from tires, treeholes, extruded polystyrene foam containers, discarded plastic cups, old recycling bins and oviposition traps. Aedes albopictus larvae were collected with Aedes japonicus (Theobald), Anopheles punctipennis (Say), Culex pipiens Linnaeus, Ochlerotatus hendersoni (Cockerell), Ochlerotatus triseriatus (Say) and Orthopodomyia signifera (Coquillett). Adult female and male specimens were collected from Biogents sentinel traps (Biogents AG, Regensburg, Germany), as well as Centers for Disease Control and Prevention miniature light traps (CDC, Atlanta, GA, U.S.A.), and also as they alighted on the investigators. Peak adult collections occurred in September during epidemiological week 37. We also collected Aedes (Stegomyia) aegypti (Linnaeus), a new record for Canada, in 2016 and from two new collection sites in 2017. The 2017 collections were 3.5 km north and 19.4 km south of the index site. The present study adds to the increasing number of studies reporting range expansions of these mosquito species.
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Affiliation(s)
- B V Giordano
- Centre for Vector-Borne Diseases, Brock University, St Catharines, Canada
- Centre for Biotechnology, Brock University, St Catharines, Canada
- Entomogen Inc., St Catharines, Canada
| | | | - P Liang
- Centre for Vector-Borne Diseases, Brock University, St Catharines, Canada
- Centre for Biotechnology, Brock University, St Catharines, Canada
- Department of Biological Sciences, Brock University, St Catharines, Canada
| | - M P Nelder
- Enteric, Zoonotic and Vector-Borne Diseases Unit, Public Health Ontario, Toronto, Canada
| | - C Russell
- Enteric, Zoonotic and Vector-Borne Diseases Unit, Public Health Ontario, Toronto, Canada
| | - F F Hunter
- Centre for Vector-Borne Diseases, Brock University, St Catharines, Canada
- Centre for Biotechnology, Brock University, St Catharines, Canada
- Entomogen Inc., St Catharines, Canada
- Department of Biological Sciences, Brock University, St Catharines, Canada
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Drago A, Simonato G, Vettore S, Martini S, Marcer F, di Regalbono AF, Cassini R. Efficacy of Aquatain ® Against Culex pipiens Complex and Aedes albopictus in Catch Basins in Italy. J Am Mosq Control Assoc 2020; 36:51-54. [PMID: 32497483 DOI: 10.2987/19-6889.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Aquatain® is an alternative larvicide formulation to the currently used larvicides. Its efficacy can be assessed monitoring emerging adults with a floating device that was recently developed for use in catch basins. In this study, the efficacy of Aquatain in controlling Aedes albopictus and Culex pipiens complex was investigated by comparing the adults emerging from 25 treated catch basins with that of 25 control basins in northeastern Italy. Basins were monitored weekly for 9 times and the efficacy was evaluated using the Mann-Whitney U-test and calculating the inhibition of emergence at each sampling. Aquatain was effective in reducing the number of emerging mosquitoes for both species, but its duration was affected by rainfall. Intensive showers (>10 mm daily) seem to reduce the efficacy of the product, allowing an increase in emerging adults after about 2 wk. This finding suggests that climatic factors should be taken into account to decide the right time for reapplication of Aquatain during routine larval treatments.
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88
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Rhyne MN, Richards SL. Impact of the Insect Growth Regulator Pyriproxyfen on Immature Development, Fecundity, and Fertility of Aedes albopictus. J Am Mosq Control Assoc 2020; 36:11-15. [PMID: 32497477 DOI: 10.2987/19-6893.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Aedes albopictus is a vector of several arboviruses; however, control of this day-active species is difficult with ultra-low-volume insecticide treatments applied at dusk/dawn periods. In the current laboratory study, blood-fed Ae. albopictus were exposed to Archer® (insect growth regulator AI: pyriproxyfen) residue in glass bottles (to approximate barrier treatment) and allowed to oviposit. Control mosquitoes were exposed to clean bottles. To evaluate potential dilution effects of water volume, mosquitoes were allowed to oviposit in (relatively) small (59 ml water) or large (177 ml water) containers. The extent to which fecundity (number of eggs laid), fertility rate (number of larvae hatched/number of eggs laid × 100), and emergence rate (number of adults emerged/number of larvae hatched × 100) differed between groups was characterized. In the control group, 18-21 (82-95%) mosquitoes laid eggs, while only 10-11 (45-50%) of mosquitoes in the pyriproxyfen group laid eggs. These sample sizes should be considered when comparing results to other studies. Significantly lower (P = 0.0008) fecundity was observed in mosquitoes exposed to pyriproxyfen (mean ± SE) (small container: 25.2 ± 7.1, large container: 24.3 ± 7.1) compared to control mosquitoes (small container: 49.2 ± 7.8, large container: 52.7 ± 5.2). Regardless of treatment, no significant differences in fecundity were observed between mosquitoes allowed to oviposit in different-sized containers. Hatch rate was significantly lower in the pyriproxyfen group and was impacted by container size (P = 0.032) and treatment (P < 0.0001) (large, control: 61.9% ± 7.8; small, control: 38.0% ± 7.1; large, treated: 10.3% ± 2.4; small, treated: 2.9% ± 1.9). Adult emergence rates were not significantly impacted by treatment or container size. Pyriproxyfen applied as a barrier treatment may be an effective tool for controlling Ae. albopictus.
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Affiliation(s)
- Megan N Rhyne
- Environmental Health Sciences Program, Department of Health Education and Promotion, College of Health and Human Performance, East Carolina University, 3403 Carol Belk Building, 300 Curry Court, Greenville, NC 27858
| | - Stephanie L Richards
- Environmental Health Sciences Program, Department of Health Education and Promotion, College of Health and Human Performance, East Carolina University, 3403 Carol Belk Building, 300 Curry Court, Greenville, NC 27858
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Katz G, Leisnham PT, LaDeau SL. Aedes albopictus Body Size Differs Across Neighborhoods With Varying Infrastructural Abandonment. J Med Entomol 2020; 57:615-619. [PMID: 31584098 DOI: 10.1093/jme/tjz170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Indexed: 06/10/2023]
Abstract
Mosquitoes pose an increasing risk in urban landscapes, where spatial heterogeneity in juvenile habitat can influence fine-scale differences in mosquito density and biting activity. We examine how differences in juvenile mosquito habitat along a spectrum of urban infrastructure abandonment can influence the adult body size of the invasive tiger mosquito, Aedes albopictus (Skuse) (Diptera: Culicidae). Adult Ae. albopictus were collected across 3 yr (2015-2017) from residential blocks in Baltimore, MD, that varied in abandonment level, defined by the proportion of houses with boarded-up doors. We show that female Ae. albopictus collected from sites with higher abandonment were significantly larger than those collected from higher income, low abandonment blocks. Heterogeneity in mosquito body size, including wing length, has been shown to reflect differences in important traits, including longevity and vector competence. The present work demonstrates that heterogeneity in female size may reflect juvenile habitat variability across the spatial scales most relevant to adult Aedes dispersal and human exposure risk in urban landscapes. Previous work has shown that failure to manage abandonment and waste issues in impoverished neighborhoods supports greater mosquito production, and this study suggests that mosquitoes in these same neighborhoods could live longer, produce more eggs, and have different vector potential.
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Affiliation(s)
- Grace Katz
- Cary Institute of Ecosystem Studies, Millbrook, NY
| | - Paul T Leisnham
- Department of Environmental Science and Technology, University of Maryland, College Park, MD
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90
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Tran BL, Tseng WC, Chen CC, Liao SY. Estimating the Threshold Effects of Climate on Dengue: A Case Study of Taiwan. Int J Environ Res Public Health 2020; 17:ijerph17041392. [PMID: 32098179 PMCID: PMC7068348 DOI: 10.3390/ijerph17041392] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/15/2020] [Accepted: 02/18/2020] [Indexed: 11/24/2022]
Abstract
Climate change is regarded as one of the major factors enhancing the transmission intensity of dengue fever. In this study, we estimated the threshold effects of temperature on Aedes mosquito larval index as an early warning tool for dengue prevention. We also investigated the relationship between dengue vector index and dengue epidemics in Taiwan using weekly panel data for 17 counties from January 2012 to May 2019. To achieve our goals, we first applied the panel threshold regression technique to test for threshold effects and determine critical temperature values. Data were then further decomposed into different sets corresponding to different temperature regimes. Finally, negative binomial regression models were applied to assess the non-linear relationship between meteorological factors and Breteau index (BI). At the national level, we found that a 1°C temperature increase caused the expected value of BI to increase by 0.09 units when the temperature is less than 27.21 °C, and by 0.26 units when the temperature is greater than 27.21 °C. At the regional level, the dengue vector index was more sensitive to temperature changes because double threshold effects were found in the southern Taiwan model. For southern Taiwan, as the temperature increased by 1°C, the expected value of BI increased by 0.29, 0.63, and 1.49 units when the average temperature was less than 27.27 °C, between 27.27 and 30.17 °C, and higher than 30.17 °C, respectively. In addition, the effects of precipitation and relative humidity on BI became stronger when the average temperature exceeded the thresholds. Regarding the impacts of climate change on BI, our results showed that the potential effects on BI range from 3.5 to 54.42% under alternative temperature scenarios. By combining threshold regression techniques with count data regression models, this study provides evidence of threshold effects between climate factors and the dengue vector index. The proposed threshold of temperature could be incorporated into the implementation of public health measures and risk prediction to prevent and control dengue fever in the future.
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Affiliation(s)
| | | | | | - Shu-Yi Liao
- Correspondence: ; Tel.: +886 4 2284 0349 (ext. 208)
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Benelli G, Pavela R, Rakotosaona R, Nzekoue FK, Canale A, Nicoletti M, Maggi F. Insecticidal and mosquito repellent efficacy of the essential oils from stem bark and wood of Hazomalania voyronii. J Ethnopharmacol 2020; 248:112333. [PMID: 31654797 DOI: 10.1016/j.jep.2019.112333] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/02/2019] [Accepted: 10/21/2019] [Indexed: 06/10/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The use of Hazomalania voyronii, popularly known as hazomalana, to repel mosquitoes and resist against insect attacks is handed down from generation to generation in Madagascar. In the present study, we investigated the ability of the essential oils (EOs) obtained from the stem wood, fresh and dry bark of H. voyronii to keep important mosquito vectors (Aedes aegypti and Culex quinquefasciatus) away, as well as their toxicity on three insect species of agricultural and public health importance (Cx. quinquefasciatus, Musca domestica and Spodoptera littoralis). MATERIALS AND METHODS Hydrodistillation was used to obtain EOs from stem wood, fresh and dry bark. The chemical compositions were achieved by gas chromatography-mass spectrometry (GC-MS). Toxicity assays using stem wood and bark EOs were performed on larvae of Cx. quinquefasciatus and S. littoralis, and adults of M. domestica by WHO and topical application methods, respectively. Mosquito repellent activity of the most effective EO, i.e. the bark one, was determined on human volunteers by arm-in-cage tests, and results were compared with that of the commercial repellent N,N-ddiethyl-m-toluamide (DEET). RESULTS The H. voyronii EOs were characterized by oxygenated monoterpenes with perilla aldehyde (30.9-47.9%) and 1,8-cineole (19.7-33.2%) as the main constituents. The fresh and dry bark EOs were the most active on Cx. quinquefasciatus and S. littoralis larvae, respectively, with LC50/LD50 of 65.5 mg L-1, and 50.5 μg larva-1; the EOs from wood and fresh bark displayed the highest toxicity on M. domestica (LD50 values 60.8 and 65.8 μg adult-1, respectively). Repellence assay revealed an almost complete protection (>80%) from both mosquito species for 30 min when pure fresh bark EO was applied on the volunteers' arm, while DEET 10% repelled >80% of the mosquitoes up to 120 min from application. CONCLUSION The traditional use of the bark EO to repel insects has been demonstrated although an extended-release formulation based on H. voyronii EOs is needed to increase the repellent effect over time. A wide spectrum of insecticidal activity has been provided as well, suggesting a possible use of H. voyronii EOs in the fabrication of green repellents and insecticides useful to control mosquito vectors and agricultural pests.
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Affiliation(s)
- Giovanni Benelli
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy.
| | - Roman Pavela
- Crop Research Institute, Prague, Czech Republic; Department of Plant Protection, Czech University of Life Sciences, Prague, Czech Republic.
| | - Rianasoambolanoro Rakotosaona
- Institut Malgache de Recherches Appliquées, Association-Fondation Rakoto Ratsimamanga, Avarabohitra Itaosy, Antananarivo, Madagascar.
| | | | - Angelo Canale
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy.
| | | | - Filippo Maggi
- School of Pharmacy, University of Camerino, Camerino, Italy.
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Chen J, Aimanova KG, Gill SS. Aedes cadherin receptor that mediates Bacillus thuringiensis Cry11A toxicity is essential for mosquito development. PLoS Negl Trop Dis 2020; 14:e0007948. [PMID: 32012156 PMCID: PMC7018227 DOI: 10.1371/journal.pntd.0007948] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 02/13/2020] [Accepted: 11/25/2019] [Indexed: 11/20/2022] Open
Abstract
Aedes cadherin (AaeCad, AAEL024535) has been characterized as a receptor for Bacillus thuringiensis subsp. israelensis (Bti) Cry11A toxins. However, its role in development is still unknown. In this study, we modified the cadherin gene using ZFN and TALEN. Even though we obtained heterozygous deletions, no homozygous mutants were viable. Because ZFN and TALEN have lower off-targets than CRISPR/Cas9, we conclude the cadherin gene is essential for Aedes development. In contrast, in lepidopteran insects loss of a homologous cadherin does not appear to be lethal, since homozygous mutants are viable. To analyze the role of AaeCad in vivo, we tagged this protein with EGFP using CRISPR-Cas9-mediated homologous recombination and obtained a homozygous AaeCad-EGFP line. Addition of Aedes Rad51 mRNA enhanced the rate of recombination. We then examined AaeCad protein expression in most tissues and protein dynamics during mosquito development. We observe that AaeCad is expressed in larval and adult midgut-specific manner and its expression pattern changed during the mosquito development. Confocal images showed AaeCad has high expression in larval caecae and posterior midgut, and also in adult midgut. Expression of AaeCad is observed primarily in the apical membranes of epithelial cells, and not in cell-cell junctions. The expression pattern observed suggests AaeCad does not appear to play a role in these junctions. However, we cannot exclude its role beyond cell-cell adhesion in the midgut. We also observed that Cry11A bound to the apical side of larval gastric caecae and posterior midgut cells exactly where AaeCad-EGFP was expressed. Their co-localization suggests that AaeCad is indeed a receptor for the Cry11A toxin. Using this mosquito line we also observed that low doses of Cry11A toxin caused the cells to slough off membranes, which likely represents a defense mechanism, to limit cell damage from Cry11A toxin pores formed in the cell membrane. A number of receptors for Bt Cry toxins, have been identified and characterized, including cadherin proteins. However, the role of these proteins in the insect is unknown and there have been few efforts to elucidate their function. First, in this study we show that in the mosquito, Aedes aegypti, the cadherin protein is essential for development. Secondly, we provide evidence that AaeCad plays a role in the apical membrane and the maintenance of midgut integrity by gene tagging using CRISPR/Cas9, which overcomes the limitation of receptor localization using antibodies in previous studies. These investigations are helpful to further investigate the physiological function of AaeCad. Moreover, this study demonstrated successful tagging of an essential gene with fluorescence protein in a non-model insect. In addition, this study showed that epithelium thinning is possibly a conserved mechanism for host defense against pore-forming toxins, like Cry11A.
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Affiliation(s)
- Jianwu Chen
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California, United States of America
| | - Karly G. Aimanova
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California, United States of America
| | - Sarjeet S. Gill
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California, United States of America
- * E-mail:
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93
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Mogi M, Armbruster PA, Tuno N. Differences in Responses to Urbanization Between Invasive Mosquitoes, Aedes japonicus japonicus (Diptera: Culicidae) and Aedes albopictus, in Their Native Range, Japan. J Med Entomol 2020; 57:104-112. [PMID: 31586393 DOI: 10.1093/jme/tjz145] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Indexed: 06/10/2023]
Abstract
The Asian mosquitoes, Aedes albopictus (Skuse) and Aedes japonicus japonicus (Theobald), have invaded North America, Europe, and other regions since the late 20th century. In invasive ranges, Ae. albopictus has well been recognized as urban, domestic species, whereas views about the macrohabitats of Ae. j. japonicus are inconsistent. Previous reports in Japan suggest the disappearance of Ae. j. japonicus from metropolises. However, container-mosquito larvae have not been inspected simultaneously for various macro and microhabitats in metropolises in Japan. The current study in Fukuoka City, a metropolis in southwest Japan, confirmed the absence of Ae. j. japonicus irrespective of macrohabitats (temples with graveyards, shrines, public graveyards, cultivated bamboo groves, and urban forests, all within the area densely inhabited by humans) and microhabitats (container types). In contrast, Ae. albopictus was dominant throughout the macro and microhabitats except forest tree holes rich with competitive species. Past records indicate the disappearance of Ae. j. japonicus from metropolitan Fukuoka within the last 70 yr. Based on careful examination of available evidence, we concluded that 1) both species benefit from human-made environments with artificial containers free from competitors, 2) Ae. j. japonicus disappeared due to hot, dry summer conditions facilitated by urban heat-island effects and a decrease in favored mammal hosts, and 3) Ae. albopictus has proliferated with higher tolerance to hot, dry climate and a wider blood-feeding host-range including humans. This difference is important for efficient control of each species as well as predicting and preventing the expansion into new distribution ranges.
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Affiliation(s)
- Motoyoshi Mogi
- Division of Parasitology, Faculty of Medicine, Saga University, Nabeshima, Saga, Japan (retired)
| | | | - Nobuko Tuno
- Laboratory of Ecology, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan
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94
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Myer MH, Fizer CM, Mcpherson KR, Neale AC, Pilant AN, Rodriguez A, Whung PY, Johnston JM. Mapping Aedes aegypti (Diptera: Culicidae) and Aedes albopictus Vector Mosquito Distribution in Brownsville, TX. J Med Entomol 2020; 57:231-240. [PMID: 31400202 PMCID: PMC6951034 DOI: 10.1093/jme/tjz132] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Indexed: 06/10/2023]
Abstract
Aedes mosquitoes are vectors of several emerging diseases and are spreading worldwide. We investigated the spatiotemporal dynamics of Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) mosquito trap captures in Brownsville, TX, using high-resolution land cover, socioeconomic, and meteorological data. We modeled mosquito trap counts using a Bayesian hierarchical mixed-effects model with spatially correlated residuals. The models indicated an inverse relationship between temperature and mosquito trap counts for both species, which may be due to the hot and arid climate of southern Texas. The temporal trend in mosquito populations indicated Ae. aegypti populations peaking in the late spring and Ae. albopictus reaching a maximum in winter. Our results indicated that seasonal weather variation, vegetation height, human population, and land cover determine which of the two Aedes species will predominate.
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Affiliation(s)
- Mark H Myer
- ORISE U.S. Environmental Protection Agency, Athens, GA
| | | | | | - Anne C Neale
- U.S. Environmental Protection Agency, Durham, NC
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Yee DA, Nelsen JA, Deerman JH, Dean CL, Price TL, Rogers RE, Varnado WC. Oviposition Responses and Potential Larval Control Methods of Aedes albopictus (Diptera: Culicidae) in Downspout Extensions. J Med Entomol 2020; 57:224-230. [PMID: 31576407 DOI: 10.1093/jme/tjz159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Indexed: 06/10/2023]
Abstract
Aedes albopictus (Skuse) is an important invasive species and vector of several important arboviruses across the globe. This species uses small water-holding cryptic containers as egg laying sites, which pose serious challenges to effective control of adult mosquito populations. Herein, we examined the response of gravid female Ae. albopictus to various features of common downspout extension tubes associated with human dwellings and the effectiveness of control efforts to eliminate larvae. Controlled field trials quantified oviposition in 1) extensions versus rubber bowls meant to mimic other container types, 2) among different shapes and materials of extensions, and 3) among different colors of extensions. We also investigated how flushing and use of Bti larvicides could control larvae. Females were more likely to lay eggs in flat plastic or metal extensions compared to rubber bowls. Eggs were also more plentiful in flat plastic extensions versus either corrugated or metal, and dark brown corrugated extensions had more eggs compared to tan or white. Flushing reduced nearly all larvae when the extensions were properly angled, and applications of Bti pellets or dunks were effective at killing most larvae. We show that dark extensions were preferred over other colors, and that larvae can be effectively removed with minimal effort. However, effective control will likely only come from better education of the public about proper installation of extensions.
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Affiliation(s)
- Donald A Yee
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS
| | - Joseph A Nelsen
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS
| | - James H Deerman
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS
- Bureau of Environmental Health, Mississippi Department of Health, Jackson, MS
| | - Catherine L Dean
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS
| | - Taylor L Price
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS
| | - Rachel E Rogers
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS
| | - Wendy C Varnado
- Bureau of Environmental Health, Mississippi Department of Health, Jackson, MS
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96
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Kamgang B, Vazeille M, Tedjou AN, Wilson-Bahun TA, Yougang AP, Mousson L, Wondji CS, Failloux AB. Risk of dengue in Central Africa: Vector competence studies with Aedes aegypti and Aedes albopictus (Diptera: Culicidae) populations and dengue 2 virus. PLoS Negl Trop Dis 2019; 13:e0007985. [PMID: 31887138 PMCID: PMC6953884 DOI: 10.1371/journal.pntd.0007985] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/10/2020] [Accepted: 12/10/2019] [Indexed: 02/02/2023] Open
Abstract
Introduction Dengue is the most important mosquito-borne diseases worldwide but was considered scarce in West-Central Africa. During the last decade, dengue outbreaks have increasingly been reported in urban foci in this region suggesting major epidemiological changes. However, in Central Africa where both vectors, Aedes aegypti and Aedes albopictus are well established, the role of each species in dengue transmission remains poorly investigated. Methodology/Principal findings Field-collected strains of Ae. aegypti and Ae. albopictus from different ecological settings in Central Africa were experimentally challenged with dengue 2 virus (DENV-2). Mosquitoes were analysed at 14- and 21-days post-infection. Analysis provide evidence that both Ae. aegypti and Ae. albopictus in Central Africa were able to transmit dengue virus with Ae. aegypti exhibiting a higher transmission rate. Unexpectedly, two Ae. aegypti populations from Bénoué and Maroua, in northern Cameroon, were not able to transmit DENV-2. Conclusions/Significance We conclude that both Ae. aegypti and Ae. albopictus are susceptible to DENV-2 and may intervene as active dengue vectors. These findings highlight the urgent need to plan a vector surveillance program and control methods against dengue vectors in Central Africa in order to prevent future outbreaks. Dengue virus (DENV) is a flavivirus mainly transmitted to humans through the bite of infected mosquitoes notably Aedes aegypti and Aedes albopictus. In Central Africa where both vectors, Ae. aegypti and Ae. albopictus are well established, the role of each species in dengue transmission remains poorly investigated. Here, we assessed the vector competence of Ae. aegypti and Ae. albopictus collected in different ecological settings in Central Africa to transmit dengue 2 virus (DENV-2). We provide evidence that both Ae. aegypti and Ae. albopictus in Central Africa were able to transmit dengue virus with Ae. aegypti exhibiting a higher transmission rate. These findings could increase the risk of dengue outbreak in the region and emphasize the need for a comprehensive vector surveillance program to prevent and preparedness for an intervention in case of outbreaks.
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Affiliation(s)
- Basile Kamgang
- Centre for Research in Infectious Diseases, Department of Medical Entomology, Yaoundé, Cameroon
- * E-mail: ,
| | - Marie Vazeille
- Institut Pasteur, Department of Virology, Unit of Arboviruses and Insect Vectors, Paris, France
| | - Armel N. Tedjou
- Centre for Research in Infectious Diseases, Department of Medical Entomology, Yaoundé, Cameroon
- Department of Animal Biology, Faculty of Sciences, University of Yaoundé I, Yaoundé, Cameroon
| | - Theodel A. Wilson-Bahun
- Centre for Research in Infectious Diseases, Department of Medical Entomology, Yaoundé, Cameroon
- Faculty of Science and Technology, Marien Ngouabi University, Brazzaville, Congo
| | - Aurélie P. Yougang
- Centre for Research in Infectious Diseases, Department of Medical Entomology, Yaoundé, Cameroon
- Department of Animal Biology, Faculty of Sciences, University of Yaoundé I, Yaoundé, Cameroon
| | - Laurence Mousson
- Institut Pasteur, Department of Virology, Unit of Arboviruses and Insect Vectors, Paris, France
| | - Charles S. Wondji
- Centre for Research in Infectious Diseases, Department of Medical Entomology, Yaoundé, Cameroon
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Anna-Bella Failloux
- Institut Pasteur, Department of Virology, Unit of Arboviruses and Insect Vectors, Paris, France
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Mao Z, Wang W, Su R, Gu G, Liu ZL, Lai D, Zhou L. Hyalodendrins A and B, New Decalin-Type Tetramic Acid Larvicides from the Endophytic Fungus Hyalodendriella sp. Ponipodef12. Molecules 2019; 25:molecules25010114. [PMID: 31892246 PMCID: PMC6982915 DOI: 10.3390/molecules25010114] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/23/2019] [Accepted: 12/24/2019] [Indexed: 01/05/2023] Open
Abstract
Two new decalin/tetramic acid hybrid metabolites, hyalodendrins A (1) and B (2) were isolated from plant endophytic fungus Hyalodendriella sp. Ponipodef12. The structures of the new compounds were elucidated by analysis of the spectroscopic data, including NMR, HRMS and ECD, and by chemical conversion. Compounds 1 and 2 were phomasetin analogues, and both showed potent larvicidal activity against the fourth-instar larvae of Aedes aegypti with the median lethal dose (LC50) values of 10.31 and 5.93 μg/mL, respectively.
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Affiliation(s)
- Ziling Mao
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China; (Z.M.); (W.W.); (R.S.); (G.G.)
| | - Weixuan Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China; (Z.M.); (W.W.); (R.S.); (G.G.)
| | - Ruixue Su
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China; (Z.M.); (W.W.); (R.S.); (G.G.)
| | - Gan Gu
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China; (Z.M.); (W.W.); (R.S.); (G.G.)
| | - Zhi Long Liu
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing 100193, China;
| | - Daowan Lai
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China; (Z.M.); (W.W.); (R.S.); (G.G.)
- Correspondence: (D.L.); (L.Z.); Tel.: +86-10-6273-1199 (L.Z.)
| | - Ligang Zhou
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China; (Z.M.); (W.W.); (R.S.); (G.G.)
- Correspondence: (D.L.); (L.Z.); Tel.: +86-10-6273-1199 (L.Z.)
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98
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Wu S, Ren H, Chen W, Li T. Neglected Urban Villages in Current Vector Surveillance System: Evidences in Guangzhou, China. Int J Environ Res Public Health 2019; 17:ijerph17010002. [PMID: 31861276 PMCID: PMC6981632 DOI: 10.3390/ijerph17010002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 12/14/2019] [Accepted: 12/15/2019] [Indexed: 12/28/2022]
Abstract
Numerous urban villages (UVs) with substandard living conditions that cause people to live there with vulnerability to health impacts, including vector-borne diseases such as dengue fever (DF), are major environmental and public health concerns in highly urbanized regions, especially in developing countries. It is necessary to explore the relationship between UVs and vector for effectively dealing with these problems. In this study, land-use types, including UVs, normal construction land (NCL), unused land (UL), vegetation, and water, were retrieved from the high-resolution remotely sensed imagery in the central area of Guangzhou in 2017. The vector density from May to October in 2017, including Aedes. albopictus (Ae. albopictus)’s Breteau index (BI), standard space index (SSI), and adult density index (ADI) were obtained from the vector surveillance system implemented by the Guangzhou Center for Disease Control and Prevention (CDC). Furthermore, the spatial and temporal patterns of vector monitoring sites and vector density were analyzed on a fine scale, and then the Geodetector tool was further employed to explore the relationships between vector density and land-use types. The monitoring sites were mainly located in NCL (55.70%–56.44%) and UV (13.14%–13.92%). Among the total monitoring sites of BI (79), SSI (312), and ADI (326), the random sites accounted for about 88.61%, 97.12%, and 98.47%, respectively. The density of Ae. albopictus was temporally related to rainfall and temperature and was obviously differentiated among different land-use types. Meanwhile, the grids with higher density, which were mostly concentrated in the Pearl River fork zone that collects a large number of UVs, showed that the density of Ae. albopictus was spatially associated with the UVs. Next, the results of the Geodetector illustrated that UVs posed great impact on the density of Ae. albopictus across the central region of Guangzhou. We suggest that the number of monitoring sites in the UVs should be appropriately increased to strengthen the current vector surveillance system in Guangzhou. This study will provide targeted guidance for local authorities, making more effective control and prevention measures on the DF epidemics.
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Affiliation(s)
- Sijia Wu
- State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A Datun Road, Chaoyang District, Beijing 100101, China;
- College of Geographical Science, Fujian Normal University, No.8 Shangsan Road, Fuzhou 350007, China;
| | - Hongyan Ren
- State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A Datun Road, Chaoyang District, Beijing 100101, China;
- Correspondence: (H.R.); (T.L.)
| | - Wenhui Chen
- College of Geographical Science, Fujian Normal University, No.8 Shangsan Road, Fuzhou 350007, China;
| | - Tiegang Li
- Department of Infectious Diseases, Guangzhou Center for Disease Control and Prevention, Guangzhou 510440, China
- Correspondence: (H.R.); (T.L.)
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Abstract
Aedes albopictus, the Asian tiger mosquito, is an important nuisance mosquito species and known vector of arboviruses such as dengue, chikungunya, and Zika. Despite their cosmopolitan distribution around the world, there is a paucity of accurate predictive models based on rates of development at different temperatures (degree-day models). These types of models can benefit mosquito control districts by predicting when to target early-season larval development, when populations are likely at their lowest levels. In this study, we determined the effect of temperature and nutrient levels on the development rates and male and female adult size of 2 Ae. albopictus populations: one field-collected, the other a 20-year-old lab colony. We found relatively small differences in the effects of temperature and nutrient levels between populations. Data from these studies were used to create a predictive degree-day model, which when tested in New Jersey correlated with field observations of early-season field populations of Ae. albopictus. While other important factors, such as day length and fluctuating temperatures, should be evaluated, data from this study will contribute to the development of operational strategies to effectively time early-season larviciding against this species.
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Phanitchat T, Apiwathnasorn C, Sungvornyothin S, Samung Y, Dujardin S, Dujardin JP, Sumruayphol S. Geometric morphometric analysis of the effect of temperature on wing size and shape in Aedes albopictus. Med Vet Entomol 2019; 33:476-484. [PMID: 31125148 DOI: 10.1111/mve.12385] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 03/20/2019] [Accepted: 04/18/2019] [Indexed: 06/09/2023]
Abstract
Wing geometry helps to identify mosquito species, even cryptic ones. On the other hand, temperature has a well-known effect on insect metric properties. Can such effects blur the taxonomic signal embedded in the wing? Two strains of Aedes albopictus (laboratory and field strain) were examined under three different rearing temperatures (26, 30 and 33 °C) using landmark- and outline-based morphometric approaches. The wings of each experimental line were compared with Aedes aegypti. Both approaches indicated similar associations between wing size and temperature. For the laboratory strain, the wing size significantly decreased as the temperature increased. For the field strain, the largest wings were observed at the intermediate temperature. The two morphometric approaches describing shape showed different sensibilities to temperature. For both strains and sexes, the landmark-based approach disclosed significant wing shape changes with temperature changes. The outline-based approach showed lesser effects, detecting significant changes only in laboratory females and in field males. Despite the size and shape changes induced by temperature, the two strains of Ae. albopictus were always distinguished from Ae. aegypti. The present study confirms the lability of size. However, it also suggests that, despite environmentally-induced variation, the architecture of the wing still provides a strong taxonomic signal.
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Affiliation(s)
- T Phanitchat
- Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - C Apiwathnasorn
- Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - S Sungvornyothin
- Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Y Samung
- Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - S Dujardin
- IRD, UMR INTERTRYP IRD, CIRAD, University of Montpellier, F-34398 Montpellier, France
| | - J-P Dujardin
- IRD, UMR INTERTRYP IRD, CIRAD, University of Montpellier, F-34398 Montpellier, France
| | - S Sumruayphol
- Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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