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Rose NH, Shepard JJ, Ayala D. Establishing Colonies from Field-Collected Mosquitoes: Special Accommodations for Wild Strains. Cold Spring Harb Protoc 2024; 2024:pdb.top107654. [PMID: 37208146 DOI: 10.1101/pdb.top107654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A researcher may have many reasons for wanting to establish new laboratory colonies from field-collected mosquitoes. In particular, the ability to study the diversity found within and among natural populations in a controlled laboratory environment opens up a wide range of possibilities for understanding how and why burdens of vector-borne disease vary over space and time. However, field-collected mosquitoes are often more difficult to work with than established laboratory strains, and considerable logistical challenges are involved in safely transporting field-collected mosquitoes into the laboratory. Here, we provide advice for researchers working with Aedes aegypti, Anopheles gambiae, and Culex pipiens, as well as notes on other closely related species. We provide guidance on each stage of the life cycle and highlight the life stages for which it is easiest to initiate new laboratory colonies for each species. In accompanying protocols, we provide methods detailing Ae. aegypti egg collection and hatching as well as how to transport larvae and pupae from the field.
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Affiliation(s)
- Noah H Rose
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544, USA
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey 08544, USA
| | - John J Shepard
- Department of Entomology and Center for Vector Biology and Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511, USA
| | - Diego Ayala
- MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier BP 64501, 34394, France
- Medical Entomology Unit, Institut Pasteur de Madagascar, Antananarivo BP1274, 101, Madagascar
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2
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Gomes B, Brant FGC, Pereira-Pinto CJ, Welbert JP, Costa JPS, Yingling AV, Hurwitz I, David MR, Genta FA. The impact of yeast-encapsulated orange oil in Aedes aegypti oviposition. PLoS One 2024; 19:e0301816. [PMID: 38743802 PMCID: PMC11093346 DOI: 10.1371/journal.pone.0301816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 03/24/2024] [Indexed: 05/16/2024] Open
Abstract
The yeast-encapsulated orange oil (YEOO) is a novel larvicide under development against vector mosquitoes. Despite its efficiency against Aedes aegypti (L.) in small scale experiments, its applicability in vector control can be influenced by other effects on mosquito behaviour or physiology. For this reason, the impact of YEOO particles in mosquito oviposition was evaluated in laboratory and semi-field conditions. Oviposition assays with one gravid Aedes aegypti female were carried under laboratory and semi-field conditions with natural light and temperature fluctuation. For all ovitraps, the number of eggs was manually counted in the wooden paddle and in the solution of each ovitrap. The proportion of eggs between substrates (wooden paddle and solution) varied between conditions, with females in laboratory presenting a lower preference to lay eggs in paddles when compared with studies in semi-field. This behaviour shifts in laboratory can create challenges to extrapolate results from laboratory to the field. Here, studies in both conditions indicate a similar impact of YEOO particles in Aedes aegypti oviposition. The potential treatment concentration of YEOO particles presents a strong repellent/deterrent effect (-0.559 > OAI > -0.760) within the initial 72h of application when compared with water, and weak repellent/deterrent signal (OAI = -0.220) when compared against inactivated yeast. Control ovitraps with water were more positive for egg presence than treated ovitraps, while ovitraps with YEOO particles and inactivated yeast present similar number of positive ovitraps. It is possible that the repellent/deterrent action is partially driven by the delivery system, since most times Citrus sinensis EO oviposition repellent/deterrent signal is weak, and it seem influenced by solvent/delivery used. However, it is unclear how the yeast wall that protect/surrounds the orange oil will negatively affect oviposition since live yeast are normally consider an attractant for mosquito oviposition.
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Affiliation(s)
- Bruno Gomes
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz (IOC-Fiocruz), Rio de Janeiro, Brazil
- Instituto Nacional de Endemias Rurais (INERU-Fiocruz), Rio de Janeiro, Brazil
| | - Fabiane G. Caldeira Brant
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz (IOC-Fiocruz), Rio de Janeiro, Brazil
| | - Camila J. Pereira-Pinto
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz (IOC-Fiocruz), Rio de Janeiro, Brazil
| | - Juliana P. Welbert
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz (IOC-Fiocruz), Rio de Janeiro, Brazil
| | - Jean P. S. Costa
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz (IOC-Fiocruz), Rio de Janeiro, Brazil
- Instituto Nacional de Endemias Rurais (INERU-Fiocruz), Rio de Janeiro, Brazil
| | - Alexandra V. Yingling
- Center for Global Health, University of New Mexico Health Sciences, Albuquerque, NM, United States of America
| | - Ivy Hurwitz
- Center for Global Health, University of New Mexico Health Sciences, Albuquerque, NM, United States of America
| | - Mariana R. David
- Laboratório de Mosquitos Transmissores de Hematozoários, Instituto Oswaldo Cruz (IOC-Fiocruz), Rio de Janeiro, Brazil
| | - Fernando A. Genta
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz (IOC-Fiocruz), Rio de Janeiro, Brazil
- Instituto Nacional de Endemias Rurais (INERU-Fiocruz), Rio de Janeiro, Brazil
- Instituto Nacional de Ciência E Tecnologia Em Entomologia Molecular, Rio de Janeiro, Brazil
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3
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David MR, Maciel‐de‐Freitas R, Petersen MT, Bray D, Hawkes FM, Fernández‐Grandon GM, Young S, Gibson G, Hopkins RJ. Aedes aegypti oviposition-sites choice under semi-field conditions. MEDICAL AND VETERINARY ENTOMOLOGY 2023; 37:683-692. [PMID: 37265439 PMCID: PMC10946600 DOI: 10.1111/mve.12670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 05/12/2023] [Indexed: 06/03/2023]
Abstract
Vector control is still the recommended approach to avoid arbovirus outbreaks. Herein, we investigate oviposition preferences of Aedes aegypti (Diptera: Culicidae) females under a semi-field structure Rio de Janeiro, Brazil. For that, in Experiment 1, we used two settings: 'Single items', which included as containers drain, beer bottle, bucket, car tyre, water tank, and a potted Peace Lily (Spathiphyllum wallisii) in a saucer with water, or 'Multiple containers', as an urban simulation, in which one drain, two additional beer bottles, and an extra plant pot saucer were added. Experiment 2 (sensory cues) used five variations of potted plant, each one varying in the range of sensory cues known to attract gravid females to oviposition containers. Our results indicate that gravid Ae. aegypti prefer to oviposit close to the ground and in open water containers with organic compounds from plant watering. Domestic large artificial containers containing tap water received significantly fewer eggs, except for the car tyre, which exhibited as many eggs as the potted plant. We also show that visual (potted plant shape) and olfactory clues (odour of the plant or from water containing organic matter) were equally attractive separately as were these stimuli together.
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Affiliation(s)
- Mariana R. David
- Laboratório de Mosquitos Transmissores de HematozoáriosInstituto Oswaldo CruzRio de JaneiroBrazil
| | - Rafael Maciel‐de‐Freitas
- Laboratório de Mosquitos Transmissores de HematozoáriosInstituto Oswaldo CruzRio de JaneiroBrazil
- Department of ArbovirologyBernhard‐Nocht Institute for Tropical MedicineHamburgGermany
| | - Martha T. Petersen
- Laboratório de Mosquitos Transmissores de HematozoáriosInstituto Oswaldo CruzRio de JaneiroBrazil
| | - Daniel Bray
- Natural Resources InstituteUniversity of Greenwich, Central Avenue, Chatham MaritimeKentUK
| | - Frances M. Hawkes
- Natural Resources InstituteUniversity of Greenwich, Central Avenue, Chatham MaritimeKentUK
| | | | - Stephen Young
- Natural Resources InstituteUniversity of Greenwich, Central Avenue, Chatham MaritimeKentUK
| | - Gabriella Gibson
- Natural Resources InstituteUniversity of Greenwich, Central Avenue, Chatham MaritimeKentUK
| | - Richard J. Hopkins
- Natural Resources InstituteUniversity of Greenwich, Central Avenue, Chatham MaritimeKentUK
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4
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Sumitha MK, Kalimuthu M, Kumar MS, Paramasivan R, Kumar NP, Sunish IP, Balaji T, Sarma DK, Kumar D, Suman DS, Srivastava H, Bhowmick IP, Vaishnav K, Singh OP, Patil PB, Tyagi S, Mohanty SS, Barik TK, Uragayala S, Kumar A, Gupta B. Genetic differentiation among Aedes aegypti populations from different eco-geographical zones of India. PLoS Negl Trop Dis 2023; 17:e0011486. [PMID: 37498944 PMCID: PMC10409278 DOI: 10.1371/journal.pntd.0011486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 08/08/2023] [Accepted: 06/27/2023] [Indexed: 07/29/2023] Open
Abstract
The present study explicitly evaluated the genetic structure of Aedes aegypti Linn, the vector of dengue, chikungunya, and Zika viruses, across different geo-climatic zones of India and also elucidated the impact of ecological and topographic factors. After data quality checks and removal of samples with excess null alleles, the final analysis was performed on 589 individual samples using 10 microsatellite markers. Overall findings of this study suggested that, Ae. aegypti populations are highly diverse with moderate genetic differentiation between them. Around half of the populations (13 out of 22) formed two genetic clusters roughly associated with geographical regions. The remaining nine populations shared genetic ancestries with either one or both of the clusters. A significant relationship between genetic and geographic distance was observed, indicating isolation by distance. However, spatial autocorrelation analysis predicted the signs of long-distance admixture. Post-hoc environmental association analysis showed that 52.7% of genetic variations were explained by a combination of climatic and topographic factors, with latitude and temperature being the best predictors. This study indicated that though overall genetic differentiation among Ae. aegypti populations across India is moderate (Fst = 0.099), the differences between the populations are developing due to the factors associated with geographic locations. This study improves the understanding of the Ae. aegypti population structure in India that may assist in predicting mosquito movements across the geo-climatic zones, enabling effective control strategies and assessing the risk of disease transmission.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Devendra Kumar
- Department of Zoology, Mohanlal Sukhadia University, Udaipur, Rajasthan, India
| | - Devi Shankar Suman
- Estuarine Biology Regional Centre, Zoological Survey of India, Gopalpur-on-Sea, Ganjam, Odisha, India
| | - Hemlata Srivastava
- School of Biological Sciences, Institute of Management Studies (University Courses Campus), Ghaziabad, Delhi, India
| | | | | | - Om P. Singh
- ICMR-National Institute of Malaria Research, New Delhi, India
| | | | - Suchi Tyagi
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Suman S. Mohanty
- ICMR-National Institute for Implementation Research on Non-Communicable Diseases, Jodhpur, India
| | - Tapan Kumar Barik
- Medical Entomology Laboratory, Post Graduate Department of Zoology, Berhampur University, Ganjam, Odisha, India
| | - Sreehari Uragayala
- ICMR-National Institute of Malaria Research, Field Unit, Bengaluru, India
| | - Ashwani Kumar
- ICMR-Vector Control Research Centre, Puducherry, India
| | - Bhavna Gupta
- ICMR-Vector Control Research Centre, Field Station, Madurai, India
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5
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Facchinelli L, Badolo A, McCall PJ. Biology and Behaviour of Aedes aegypti in the Human Environment: Opportunities for Vector Control of Arbovirus Transmission. Viruses 2023; 15:636. [PMID: 36992346 PMCID: PMC10053764 DOI: 10.3390/v15030636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/02/2023] Open
Abstract
Aedes aegypti is a ubiquitous vector of arboviruses mostly in urbanised areas throughout the tropics and subtropics and a growing threat beyond. Control of Ae. aegypti is difficult and costly, and no vaccines are available for most of the viruses it transmits. With practical control solutions our goal, ideally suitable for delivery by householders in affected communities, we reviewed the literature on adult Ae. aegypti biology and behaviour, within and close to the human home, the arena where such interventions must impact. We found that knowledge was vague or important details were missing for multiple events or activities in the mosquito life cycle, such as the duration or location of the many periods when females rest between blood feeding and oviposition. The existing body of literature, though substantial, is not wholly reliable, and evidence for commonly held "facts" range from untraceable to extensive. Source references of some basic information are poor or date back more than 60 years, while other information that today is accepted widely as "fact" is not supported by evidence in the literature. Many topics, e.g., sugar feeding, resting preferences (location and duration), and blood feeding, merit being revisited in new geographical regions and ecological contexts to identify vulnerabilities for exploitation in control.
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Affiliation(s)
- Luca Facchinelli
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Athanase Badolo
- Laboratoire d’Entomologie Fondamentale et Appliquée, Université Joseph KI-ZERBO, Ouagadougou 03 BP 7021, Burkina Faso
| | - Philip J. McCall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
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6
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Acero-Sandoval MA, Palacio-Cortés AM, Navarro-Silva MA. Surveillance of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) as a Method for Prevention of Arbovirus Transmission in Urban and Seaport Areas of the Southern Coast of Brazil. JOURNAL OF MEDICAL ENTOMOLOGY 2023; 60:173-184. [PMID: 36305159 DOI: 10.1093/jme/tjac143] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Indexed: 06/16/2023]
Abstract
Entomological surveillance is a traditional method to measure presence, distribution, and seasonal variation of vectors in urban areas, and is essential to targeted control activities to prevent arbovirus transmission. Ovitraps as one of the main components of surveillance programs, enable determination of female oviposition behavior, as well as identification of seasonal variations of the vector. The goals of this study were 1) to detect the mosquitos (Aedes aegypti Linnaeus) and (Aedes albopictus Skuse) (Diptera:Culicidae), in Paranaguá city, 2) to assess ovitrap positive index (OPI), egg density index (EDI), and their relationship with meteorological variables, and 3) to evaluate the vertical transmission of dengue, Zika, and chikungunya in Ae. aegypti and Ae. albopictus. The study was carried out in urban areas of Paranaguá city, an important port region of Brazil, from June 2017 to November 2018. The city was divided into 16 area-clusters. Three-hundred and thirty-one ovitraps were installed monthly, remaining for four days in selected places. Kernel density maps were done to compare the spatiotemporal distribution of collected eggs. Areas which maintained constant oviposition associated with vector activity were identified and were found to overlap the area-clusters with the highest EDI. As viral RNA was not detected, vertical transmission was likely not a maintenance mechanism of arbovirus circulation in Ae. aegypti and Ae. albopictus vectors. This study reiterates the importance, efficiency, and feasibility of ovitraps to monitor the presence and dynamics of Aedes spp. populations.
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Affiliation(s)
- Mario Arturo Acero-Sandoval
- Laboratory of Morphology and Physiology of Culicidae and Chironomidae, Zoology Department, Federal University of Paraná, CP 19020, CEP 81531-980, Curitiba, Paraná, Brazil
| | - Angela Maria Palacio-Cortés
- Laboratory of Morphology and Physiology of Culicidae and Chironomidae, Zoology Department, Federal University of Paraná, CP 19020, CEP 81531-980, Curitiba, Paraná, Brazil
| | - Mario Antônio Navarro-Silva
- Laboratory of Morphology and Physiology of Culicidae and Chironomidae, Zoology Department, Federal University of Paraná, CP 19020, CEP 81531-980, Curitiba, Paraná, Brazil
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7
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Pimid M, Krishnan KT, Ahmad AH, Mohd Naim D, Chambers GK, Mohd Nor SA, Ab Majid AH. Parentage Assignment Using Microsatellites Reveals Multiple Mating in Aedes aegypti (Diptera: Culicidae): Implications for Mating Dynamics. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:1525-1533. [PMID: 35733165 DOI: 10.1093/jme/tjac081] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Indexed: 06/15/2023]
Abstract
The mosquito Aedes aegypti is the primary vector of the dengue, yellow fever, and chikungunya viruses. Evidence shows that Ae. aegypti males are polyandrous whereas Ae. aegypti females are monandrous in mating. However, the degree to which Ae. aegypti males and females can mate with different partners has not been rigorously tested. Therefore, this study examined the rates of polyandry via parentage assignment in three sets of competitive mating experiments using wild-type male and female Ae. aegypti. Parentage assignment was monitored using nine microsatellite DNA markers. All Ae. aegypti offspring were successfully assigned to parents with 80% or 95% confidence using CERVUS software. The results showed that both male and female Ae. aegypti mated with up to 3-4 different partners. Adults contributed differentially to the emergent offspring, with reproductive outputs ranging from 1 to 25 viable progeny. This study demonstrates a new perspective on the capabilities of male and female Ae. aegypti in mating. These findings are significant because successful deployment of reproductive control methods using genetic modification or sterile Ae. aegypti must consider the following criteria regarding their mating fitness: 1) choosing Ae. aegypti males that can mate with many different females; 2) testing how transformed Ae. aegypti male perform with polyandrous females; and 3) prioritizing the selection of polyandrous males and/or females Ae. aegypti that have the most offspring.
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Affiliation(s)
- Marcela Pimid
- Faculty of Agro Based Industry, Universiti Malaysia Kelantan, Jeli Campus, 17600 Kelantan, Malaysia
- School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Kumara Thevan Krishnan
- Faculty of Agro Based Industry, Universiti Malaysia Kelantan, Jeli Campus, 17600 Kelantan, Malaysia
| | - Abu Hassan Ahmad
- School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Darlina Mohd Naim
- School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Geoffrey K Chambers
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, 6140 Wellington, New Zealand
| | - Siti Azizah Mohd Nor
- Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Terengganu, Malaysia
| | - Abdul Hafiz Ab Majid
- Household & Structural Urban Entomology Laboratory, Vector Control Research Unit, School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia
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8
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Mulatier M, Boullis A, Vega-Rúa A. Semiochemical oviposition cues to control Aedes aegypti gravid females: state of the art and proposed framework for their validation. Parasit Vectors 2022; 15:228. [PMID: 35752845 PMCID: PMC9233825 DOI: 10.1186/s13071-022-05337-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 05/24/2022] [Indexed: 11/28/2022] Open
Abstract
In the fight against mosquito-borne diseases, odour-based lures targeting gravid females represent a promising alternative to conventional tools for both reducing mosquito populations and monitoring pathogen transmission. To be sustainable and effective, they are expected to use semiochemicals that act specifically against the targeted vector species. In control programmes directed against Aedes aegypti, several candidates of different origins (conspecifics, plants) have already been identified as potential oviposition attractants or repellents in laboratory experiments. However, few of these candidates have received validation in field experiments, studies depicting the active molecules and their mode of perception are still scarce, and there are several methodological challenges (i.e. lack of standardization, differences in oviposition index interpretation and use) that should be addressed to ensure a better reproducibility and accelerate the validation of candidates. In this review, we address the state of the art of the compounds identified as potential candidates for trap development against Ae. aegypti and their level of validation. We also offer a critical methodological analysis, highlight remaining gaps and research priorities, and propose a workflow to validate these candidates and to increase the panel of odours available to specifically trap Ae. aegypti.
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Affiliation(s)
- Margaux Mulatier
- Laboratory of Vector Control Research, Institute Pasteur of Guadeloupe, Lieu-dit Morne Jolivière, 97139, Les Abymes, Guadeloupe, France.
| | - Antoine Boullis
- TERRA, Gembloux Agro-Bio Tech, University of Liège, Avenue de la Faculté 2B, 5030, Gembloux, Belgium
| | - Anubis Vega-Rúa
- Laboratory of Vector Control Research, Institute Pasteur of Guadeloupe, Lieu-dit Morne Jolivière, 97139, Les Abymes, Guadeloupe, France
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9
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da Silva MR, Lugão PHG, Prezoto F, Chapiro G. Modeling the impact of genetically modified male mosquitoes in the spatial population dynamics of Aedes aegypti. Sci Rep 2022; 12:9112. [PMID: 35650219 PMCID: PMC9160293 DOI: 10.1038/s41598-022-12764-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 05/12/2022] [Indexed: 11/20/2022] Open
Abstract
The mosquito Aedes aegypti is the primary vector of diseases such as dengue, Zika, chikungunya, and yellow fever. Improving control techniques requires a better understanding of the mosquito’s life cycle, including spatial population dynamics in endemic regions. One of the most promising techniques consists of introducing genetically modified male mosquitoes. Several models proposed to describe this technique present mathematical issues or rely on numerous parameters, making their application challenging to real-world situations. We propose a model describing the spatial population dynamics of the Aedes aegypti in the presence of genetically modified males. This model presents some mathematical improvements compared to the literature allowing deeper mathematical analysis. Moreover, this model relies on few parameters, which we show how to obtain or estimate from the literature. Through numerical simulations, we investigate the impacts of environmental heterogeneity, the periodicity of genetically modified male releases, and released genetically modified males quantity on the population dynamics of Aedes aegypti. The main results point to that the successful application of this vector control technique relies on releasing more than a critical amount of modified males with a frequency exceeding a specific critical value.
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Affiliation(s)
- Monalisa R da Silva
- Laboratory of Applied Mathematics (LAMAP), Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil.,Computational Modeling Graduate Program, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil.,Federal Institute of the Southeast of Minas Gerais, Santos Dumont, MG, Brazil
| | - Pedro H G Lugão
- Computational Modeling Graduate Program - National Laboratory for Scientific Computing (LNCC), Petrópolis, RJ, Brazil
| | - Fábio Prezoto
- Department of Zoology, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
| | - Grigori Chapiro
- Laboratory of Applied Mathematics (LAMAP), Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil.
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10
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James LD, Winter N, Stewart ATM, Feng RS, Nandram N, Mohammed A, Duman-Scheel M, Romero-Severson E, Severson DW. Field trials reveal the complexities of deploying and evaluating the impacts of yeast-baited ovitraps on Aedes mosquito densities in Trinidad, West Indies. Sci Rep 2022; 12:4047. [PMID: 35260697 PMCID: PMC8904463 DOI: 10.1038/s41598-022-07910-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 02/25/2022] [Indexed: 11/12/2022] Open
Abstract
The use of lure-and-kill, large-volume ovitraps to control Aedes aegypti and Aedes albopictus populations has shown promise across multiple designs that target gravid females (adulticidal) or larvae post-oviposition (larvicidal). Here we report on a pilot trial to deploy 10 L yeast-baited ovitraps at select sites in Curepe, Trinidad, West Indies during July to December, 2019. Oviposition rates among ovitraps placed in three Treatment sites were compared to a limited number of traps placed in three Control areas (no Aedes management performed), and three Vector areas (subjected to standard Ministry of Health, Insect Vector Control efforts). Our goal was to gain baseline information on efforts to saturate the Treatment sites with ovitraps within 20–25 m of each other and compare oviposition rates at these sites with background oviposition rates in Control and Vector Areas. Although yeast-baited ovitraps were highly attractive to gravid Aedes females, a primary limitation encountered within the Treatment sites was the inability to gain access to residential compounds for trap placement, primarily due to residents being absent during the day. This severely limited our intent to saturate these areas with ovitraps, indicating that future studies must include plans to account for these inaccessible zones during trap placement.
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Affiliation(s)
- Lester D James
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
| | - Nikhella Winter
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
| | - Akilah T M Stewart
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
| | - Rachel Shui Feng
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
| | - Naresh Nandram
- Insect Vector Control Division, Ministry of Health, St. Augustine, Trinidad and Tobago
| | - Azad Mohammed
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
| | - Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN, USA.,Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Ethan Romero-Severson
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - David W Severson
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago. .,Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN, USA. .,Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA.
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11
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Elnour MAB, Gloria-Soria A, Azrag RS, Alkhaibari AM, Powell JR, Salim B. Population Genetic Analysis of Aedes aegypti Mosquitoes From Sudan Revealed Recent Independent Colonization Events by the Two Subspecies. Front Genet 2022; 13:825652. [PMID: 35251133 PMCID: PMC8889412 DOI: 10.3389/fgene.2022.825652] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/12/2022] [Indexed: 11/13/2022] Open
Abstract
Increases in arbovirus outbreaks in Sudan are vectored by Aedes aegypti, raising the medical importance of this mosquito. We genotyped 12 microsatellite loci in four populations of Ae. aegypti from Sudan, two from the East and two from the West, and analyzed them together with a previously published database of 31 worldwide populations to infer population structure and investigate the demographic history of this species in Sudan. Our results revealed the presence of two genetically distinct subspecies of Ae. aegypti in Sudan. These are Ae. aegypti aegypti in Eastern Sudan and Ae. aegypti formosus in Western Sudan. Clustering analysis showed that mosquitoes from East Sudan are genetically homogeneous, while we found population substructure in West Sudan. In the global context our results indicate that Eastern Sudan populations are genetically closer to Asian and American populations, while Western Sudan populations are related to East and West African populations. Approximate Bayesian Computation Analysis supports a scenario in which Ae. aegypti entered Sudan in at least two independent occasions nearly 70–80 years ago. This study provides a baseline database that can be used to determine the likely origin of new introductions for this invasive species into Sudan. The presence of the two subspecies in the country should be consider when designing interventions, since they display different behaviors regarding epidemiologically relevant parameters, such as blood feeding preferences and ability to transmit disease.
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Affiliation(s)
- Mohammed-Ahmed B. Elnour
- Department of Parasitology and Medical Entomology, Tropical Medicine Research Institute, National Center for Research, Khartoum, Sudan
| | - Andrea Gloria-Soria
- Department of Environmental Sciences, Center for Vector Biology and Zoonotic Diseases, The Connecticut Agricultural Experiment Station, New Haven, CT, United States
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, United States
| | - Rasha S. Azrag
- Department of Zoology, Faculty of Science, University of Khartoum, Khartoum, Sudan
| | - Abeer M. Alkhaibari
- Department of Biology, Faculty of Science, University of Tabuk, Tabuk, Saudi Arabia
| | - Jeffrey R. Powell
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, United States
| | - Bashir Salim
- Department of Parasitology, Faculty of Veterinary Medicine, University of Khartoum, Khartoum North, Sudan
- *Correspondence: Bashir Salim,
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Buckner EA, Williams KF, Ramirez S, Darrisaw C, Carrillo JM, Latham MD, Lesser CR. A Field Efficacy Evaluation of In2Care Mosquito Traps in Comparison with Routine Integrated Vector Management at Reducing Aedes aegypti. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2021; 37:242-249. [PMID: 34817613 DOI: 10.2987/21-7038] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Aedes aegypti is the predominant vector of dengue, chikungunya, and Zika viruses. This mosquito is difficult to control with conventional methods due to its container-inhabiting behavior and resistance to insecticides. Autodissemination of pyriproxyfen (PPF), a potent larvicide, has shown promise as an additional tool to control Aedes species in small-scale field trials. However, few large-scale field evaluations have been conducted. We undertook a 6-month-long large-scale field study to compare the effectiveness and operational feasibility of using In2Care Mosquito Traps (In2Care Traps, commercially available Aedes traps with PPF and Beauveria bassiana) compared to an integrated vector management (IVM) strategy consisting of source reduction, larviciding, and adulticiding for controlling Ae. aegypti eggs, larvae, and adults. We found that while the difference between treatments was only statistically significant for eggs and larvae (P < 0.05 for eggs and larvae and P > 0.05 for adults), the use of In2Care Traps alone resulted in 60%, 57%, and 57% fewer eggs, larvae, and adults, respectively, collected from that site compared to the IVM site. However, In2Care Trap deployment and maintenance were more time consuming and labor intensive than the IVM strategy. Thus, using In2Care Traps alone as a control method for large areas (e.g., >20 ha) may be less practical for control programs with the capacity to conduct ground and aerial larviciding and adulticiding. Based on our study results, we conclude that In2Care Traps are effective at suppressing Ae. aegypti and have the most potential for use in areas without sophisticated control programs and within IVM programs to target hotspots with high population levels and/or risk of Aedes-borne pathogen transmission.
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13
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Jasper ME, Hoffmann AA, Schmidt TL. Estimating dispersal using close kin dyads: The kindisperse R package. Mol Ecol Resour 2021; 22:1200-1212. [PMID: 34597453 DOI: 10.1111/1755-0998.13520] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 09/21/2021] [Accepted: 09/24/2021] [Indexed: 10/20/2022]
Abstract
Investigating dispersal in animal populations can be difficult, particularly for taxa that are hard to directly observe such as those that are small or rare. A promising solution may come from new approaches that use genome-wide sequence data to detect close kin dyads and estimate dispersal parameters from the distribution of these dyads. These methods have so far only been applied to mosquito populations. However, they should have broad applicability to a range of taxa, although no assessment has yet been made on their performance under different dispersal conditions and study designs. Here we develop an R package and shiny app, kindisperse, that can be used to estimate dispersal parameters from the spatial distribution of close kin. kindisperse can handle study designs that target different life stages and allows for a range of dispersal kernel shapes and organismal life histories; we provide implementation examples for a vertebrate (Antechinus) and an invertebrate (Aedes). We use simulations run in kindisperse to compare the performance of two published close kin methodologies, showing that one method produces unbiased estimates whereas the other produces downward-biased estimates. We also use kindisperse simulations to investigate how study design affects dispersal estimates, and we provide guidelines for the size and shape of sample sites as well as the number of close kin needed for accurate estimates. kindisperse is easily adaptable for application to a variety of research contexts ranging from invasive pests to threatened species where noninvasive DNA sampling can be used to detect close kin.
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Affiliation(s)
- Moshe E Jasper
- School of Biosciences, the University of Melbourne, Melbourne, Victoria, Australia
| | - Ary A Hoffmann
- School of Biosciences, the University of Melbourne, Melbourne, Victoria, Australia
| | - Thomas L Schmidt
- School of Biosciences, the University of Melbourne, Melbourne, Victoria, Australia
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14
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Morris AL, Ghani A, Ferguson N. Fine-scale estimation of key life-history parameters of malaria vectors: implications for next-generation vector control technologies. Parasit Vectors 2021; 14:311. [PMID: 34103094 PMCID: PMC8188720 DOI: 10.1186/s13071-021-04789-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 05/11/2021] [Indexed: 11/12/2022] Open
Abstract
Background Mosquito control has the potential to significantly reduce malaria burden on a region, but to influence public health policy must also show cost-effectiveness. Gaps in our knowledge of mosquito population dynamics mean that mathematical modelling of vector control interventions have typically made simplifying assumptions about key aspects of mosquito ecology. Often, these assumptions can distort the predicted efficacy of vector control, particularly next-generation tools such as gene drive, which are highly sensitive to local mosquito dynamics. Methods We developed a discrete-time stochastic mathematical model of mosquito population dynamics to explore the fine-scale behaviour of egg-laying and larval density dependence on parameter estimation. The model was fitted to longitudinal mosquito population count data using particle Markov chain Monte Carlo methods. Results By modelling fine-scale behaviour of egg-laying under varying density dependence scenarios we refine our life history parameter estimates, and in particular we see how model assumptions affect population growth rate (Rm), a crucial determinate of vector control efficacy. Conclusions Subsequent application of these new parameter estimates to gene drive models show how the understanding and implementation of fine-scale processes, when deriving parameter estimates, may have a profound influence on successful vector control. The consequences of this may be of crucial interest when devising future public health policy. Graphic abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-04789-0.
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Affiliation(s)
- Aaron L Morris
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, Norfolk Place, London, W2 1PG, UK.
| | - Azra Ghani
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, Norfolk Place, London, W2 1PG, UK
| | - Neil Ferguson
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, Norfolk Place, London, W2 1PG, UK
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15
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McLaughlin LG, Wasserberg G. Spatial Bet Hedging in Sand Fly Oviposition: Factors Affecting Skip Oviposition in Phlebotomus papatasi Sand Flies. Vector Borne Zoonotic Dis 2021; 21:280-288. [PMID: 33793344 DOI: 10.1089/vbz.2020.2737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Skip oviposition is considered as an example of spatial bet hedging and involves a tradeoff between the benefit of reducing the risk of complete reproductive failure due to stochastic loss of a breeding site and the energetic and mortality costs associated with dispersal across several oviposition sites. Skip oviposition has been studied extensively for container-breeding mosquitoes but has never been studied with sand flies. By conducting a series of bioassays using solitary gravid females exposed to varying numbers of oviposition sites and to oviposition sites of variable quality at small (oviposition jar) and medium (free-flight cage) scales, we showed that sand flies exhibited skip oviposit at both scales. Specifically, with low-quality oviposition sites, females spread their eggs across several oviposition sites with total egg clutch size remaining constant and number of eggs per oviposition site decreasing with increasing number of oviposition sites. With variable quality sites, sand flies biased their oviposition to sites containing increasing levels of organic matter (OM), but also laid eggs in poor-quality sites; a behavior consistent with spatial bet hedging. We also demonstrated that the presence of OM stimulated larger egg clutch size and increased percent skip oviposition. Skip oviposition was less frequent at the free flight cage scale. But, at this scale, females were shown to be stimulated to lay more eggs when in the presence of other females than when alone.
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Affiliation(s)
- Lexua G McLaughlin
- Department of Biology, University of North Carolina at Greensboro, Greensboro, North Carolina, USA
| | - Gideon Wasserberg
- Department of Biology, University of North Carolina at Greensboro, Greensboro, North Carolina, USA
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Boullis A, Mulatier M, Delannay C, Héry L, Verheggen F, Vega-Rúa A. Behavioural and antennal responses of Aedes aegypti (l.) (Diptera: Culicidae) gravid females to chemical cues from conspecific larvae. PLoS One 2021; 16:e0247657. [PMID: 33626104 PMCID: PMC7904138 DOI: 10.1371/journal.pone.0247657] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 02/10/2021] [Indexed: 12/24/2022] Open
Abstract
Mass trapping of gravid females represents one promising strategy for the development of sustainable tools against Aedes aegypti. However, this technique requires the development of effective odorant lures that can compete with natural breeding sites. The presence of conspecific larvae has been shown to stimulate oviposition. Hence, we evaluated the role of four major molecules previously identified from Ae. aegypti larvae (isovaleric, myristoleic, myristic [i.e. tetradecanoic], and pentadecanoic acids) on the oviposition of conspecific females, as well as their olfactory perception to evaluate their range of detection. Using flight cage assays, the preference of gravid females to oviposit in water that previously contained larvae (LHW) or containing the four larval compounds was evaluated. Then, compounds and doses inducing the highest stimulation were challenged for their efficacy against LHW. Only isovaleric acid elicited antennal response, suggesting that the other compounds may act as taste cues. Pentadecanoic acid induced significant oviposition stimulation, especially when dosed at 10 ppm. Myristoleic acid and isovaleric acid deterred oviposition at 10 and 100 ppm, while no effect on oviposition was observed with myristic acid irrespectively of the dose tested. When the four compounds were pooled to mimic larvae’s chemical signature, they favored oviposition at 1 ppm but negatively affected egg-laying at higher concentrations. When properly dosed, pentadecanoic acid and the blend of compounds may be promising lures for ovitraps as they could compete with LHW. Due to their low volatility, their effect should be further evaluated under field conditions, in addition with long-range attractants for developing effective tools against gravid females.
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Affiliation(s)
- Antoine Boullis
- Laboratory of Vector Control Research, Institute Pasteur of Guadeloupe–Lieu-dit Morne Jolivière, Les Abymes, Guadeloupe, France
| | - Margaux Mulatier
- Laboratory of Vector Control Research, Institute Pasteur of Guadeloupe–Lieu-dit Morne Jolivière, Les Abymes, Guadeloupe, France
| | - Christelle Delannay
- Laboratory of Vector Control Research, Institute Pasteur of Guadeloupe–Lieu-dit Morne Jolivière, Les Abymes, Guadeloupe, France
| | - Lyza Héry
- Laboratory of Vector Control Research, Institute Pasteur of Guadeloupe–Lieu-dit Morne Jolivière, Les Abymes, Guadeloupe, France
| | | | - Anubis Vega-Rúa
- Laboratory of Vector Control Research, Institute Pasteur of Guadeloupe–Lieu-dit Morne Jolivière, Les Abymes, Guadeloupe, France
- * E-mail:
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17
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Regilme MAF, Carvajal TM, Honnen A, Amalin DM, Watanabe K. The influence of roads on the fine-scale population genetic structure of the dengue vector Aedes aegypti (Linnaeus). PLoS Negl Trop Dis 2021; 15:e0009139. [PMID: 33635860 PMCID: PMC7946359 DOI: 10.1371/journal.pntd.0009139] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 03/10/2021] [Accepted: 01/13/2021] [Indexed: 11/30/2022] Open
Abstract
Dengue is endemic in tropical and subtropical countries and is transmitted mainly by Aedes aegypti. Mosquito movement can be affected by human-made structures such as roads that can act as a barrier. Roads can influence the population genetic structure of Ae. aegypti. We investigated the genetic structure and gene flow of Ae. aegypti as influenced by a primary road, España Boulevard (EB) with 2000-meter-long stretch and 24-meters-wide in a very fine spatial scale. We hypothesized that Ae. aegypti populations separated by EB will be different due to the limited gene flow as caused by the barrier effect of the road. A total of 359 adults and 17 larvae Ae. aegypti were collected from June to September 2017 in 13 sites across EB. North (N1-N8) and South (S1-S5) comprised of 211 and 165 individuals, respectively. All mosquitoes were genotyped at 11 microsatellite loci. AMOVA FST indicated significant genetic differentiation across the road. The constructed UPGMA dendrogram found 3 genetic groups revealing the clear separation between North and South sites across the road. On the other hand, Bayesian cluster analysis showed four genetic clusters (K = 4) wherein each individual samples have no distinct genetic cluster thus genetic admixture. Our results suggest that human-made landscape features such as primary roads are potential barriers to mosquito movement thereby limiting its gene flow across the road. This information is valuable in designing an effective mosquito control program in a very fine spatial scale.
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Affiliation(s)
- Maria Angenica F. Regilme
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Japan
- Graduate School of Science and Engineering, Ehime University, Matsuyama, Japan
- Biological Control Research Unit, Center for Natural Science and Environmental Research, De La Salle University, Manila, Philippines
- Department of Biology, De La Salle University, Manila, Philippines
| | - Thaddeus M. Carvajal
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Japan
- Graduate School of Science and Engineering, Ehime University, Matsuyama, Japan
- Biological Control Research Unit, Center for Natural Science and Environmental Research, De La Salle University, Manila, Philippines
- Department of Biology, De La Salle University, Manila, Philippines
| | - Ann–Christin Honnen
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Divina M. Amalin
- Biological Control Research Unit, Center for Natural Science and Environmental Research, De La Salle University, Manila, Philippines
- Department of Biology, De La Salle University, Manila, Philippines
| | - Kozo Watanabe
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Japan
- Graduate School of Science and Engineering, Ehime University, Matsuyama, Japan
- Biological Control Research Unit, Center for Natural Science and Environmental Research, De La Salle University, Manila, Philippines
- Department of Biology, De La Salle University, Manila, Philippines
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McGregor BL, Connelly CR. A Review of the Control of Aedes aegypti (Diptera: Culicidae) in the Continental United States. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:10-25. [PMID: 32829398 PMCID: PMC7855389 DOI: 10.1093/jme/tjaa157] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Indexed: 05/10/2023]
Abstract
Aedes aegypti (L) is an anthropophilic mosquito involved in the transmission of a variety of viral pathogens worldwide including dengue, chikungunya, yellow fever, and Zika viruses. This species, native to Africa, is well established in the continental U.S. (CONUS) and occasionally contributes to localized outbreaks of viral diseases. In the last seven decades, mosquito control programs in the CONUS have been focused on vectors of eastern equine encephalitis, St. Louis encephalitis, and West Nile viruses, as well as nuisance species. Aedes aegypti receives little control focus except during outbreak periods, which has led to a lack of information on appropriate and effective control options targeting Ae. aegypti in the CONUS. As such, in the event of an Ae. aegypti-borne arboviral outbreak in the CONUS, there are limited evidence-based control recommendations or protocols in place. Autochthonous outbreaks of Ae. aegypti-borne pathogens have occurred recently in the CONUS, including dengue outbreaks in 2010 and 2013, a chikungunya outbreak in 2014, and the 2016 outbreak of Zika virus. The increasing frequency of Ae. aegypti-borne outbreaks necessitates increased attention and research on control of this species to prevent and mitigate future outbreaks. This review consolidates and synthesizes the available literature on control of Ae. aegypti, specifically within the CONUS, focusing on data generated through operational applications as well as field and semifield experiments. The purpose of this review is to identify and highlight areas where additional research is needed. The review covers chemical control and insecticide resistance, biological control, source reduction, trapping, and alternative techniques.
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Affiliation(s)
- Bethany L. McGregor
- Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, Colorado 80521
- Oak Ridge Institute of Science and Education, 100 ORAU Way, Oak Ridge, Tennessee 37830
- USDA, Agricultural Research Service, Center for Grain and Animal Health Research, 1515 College Avenue, Manhattan, Kansas 66502
| | - C. Roxanne Connelly
- Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, Colorado 80521
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Alomar AA, Eastmond BH, Alto BW. The effects of exposure to pyriproxyfen and predation on Zika virus infection and transmission in Aedes aegypti. PLoS Negl Trop Dis 2020; 14:e0008846. [PMID: 33201875 PMCID: PMC7707533 DOI: 10.1371/journal.pntd.0008846] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 12/01/2020] [Accepted: 09/24/2020] [Indexed: 12/21/2022] Open
Abstract
Zika virus (ZIKV) is an emerging mosquito-borne pathogen that can cause global public health threats. In the absence of effective antiviral medications, prevention measures rely largely on reducing the number of adult mosquito vectors by targeting juvenile stages. Despite the importance of juvenile mosquito control measures in reducing adult population size, a full understanding of the effects of these measures in determining mosquito phenotypic traits and in mosquito-arbovirus interactions is poorly understood. Pyriproxyfen is a juvenile hormone analog that primarily blocks adult emergence, but does not cause mortality in larvae. This mechanism has the potential to work in combination with other juvenile sources of mortality in nature such as predation to affect mosquito populations. Here, we experimentally evaluated the effects of juvenile exposure to pyriproxyfen and predatory mosquito Toxorhynchites rutilus on Aedes aegypti phenotypes including susceptibility to ZIKV infection and transmission. We discovered that combined effects of pyriproxyfen and Tx. rutilus led to higher inhibition of adult emergence in Ae. aegypti than observed in pyriproxyfen or Tx. rutilus treatments alone. Adult body size was larger in treatments containing Tx. rutilus and in treatments mimicking the daily mortality of predation compared to control or pyriproxyfen treatments. Susceptibility to infection with ZIKV in Ae. aegypti was reduced in predator treatment relative to those exposed to pyriproxyfen. Disseminated infection, transmission, and titers of ZIKV in Ae. aegypti were similar in all treatments relative to controls. Our data suggest that the combination of pyriproxyfen and Tx. rutilus can inhibit adult Ae. aegypti emergence but may confer a fitness advantage in survivors and does not inhibit their vector competence for ZIKV relative to controls. Understanding the ultimate consequences of juvenile mosquito control measures on subsequent adults’ ability to transmit pathogens is critical to fully understand their overall impacts. Mosquito control approaches primarily depend on lowering the number of potential adult mosquito vectors by inhibiting juvenile stages to reduce the risk of pathogen transmission. Pyriproxyfen is a juvenile hormone analog that inhibits the emergence of adult mosquitoes by interrupting metamorphosis, but does not target larvae. This mechanism allows natural sources of mortality like predation to act in combination with pyriproxyfen to affect mosquito population size. Here, we determined the effects of juvenile exposure to pyriproxyfen and predatory mosquito Toxorhynchites rutilus on adult Aedes aegypti traits, including infection with Zika virus. Combined effects of pyriproxyfen and Tx. rutilus led to strong inhibition of adult emergence in Ae. aegypti. Treatments containing predators or those mimicking the daily mortality of predation produced larger sized adults. Susceptibility to ZIKV infection was lowest in the predator treatment and highest in the pyriproxyfen treatment. Disseminated infection, transmission, and viral titers of ZIKV were similar between treatments. Our data suggest that the combination of pyriproxyfen and predators can enhance inhibition of adult Ae. aegypti emergence, but survivors may have fitness benefits such being larger mosquitoes. Understanding the consequences of control approaches in mosquito-pathogen interactions will assist to evaluate their suitability in mosquito control programs.
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Affiliation(s)
- Abdullah A. Alomar
- University of Florida, Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Vero Beach, Florida, United States of America
| | - Bradley H. Eastmond
- University of Florida, Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Vero Beach, Florida, United States of America
| | - Barry W. Alto
- University of Florida, Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Vero Beach, Florida, United States of America
- * E-mail:
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20
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Modeling and simulation of the spatial population dynamics of the Aedes aegypti mosquito with an insecticide application. Parasit Vectors 2020; 13:550. [PMID: 33160416 PMCID: PMC7648403 DOI: 10.1186/s13071-020-04426-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 10/24/2020] [Indexed: 11/10/2022] Open
Abstract
Background The Aedes aegypti mosquito is the primary vector for several diseases. Its control requires a better understanding of the mosquitoes’ live cycle, including the spatial dynamics. Several models address this issue. However, they rely on many hard to measure parameters. This work presents a model describing the spatial population dynamics of Aedes aegypti mosquitoes using partial differential equations (PDEs) relying on a few parameters. Methods We show how to estimate model parameter values from the experimental data found in the literature using concepts from dynamical systems, genetic algorithm optimization and partial differential equations. We show that our model reproduces some analytical formulas relating the carrying capacity coefficient to experimentally measurable quantities as the maximum number of mobile female mosquitoes, the maximum number of eggs, or the maximum number of larvae. As an application of the presented methodology, we replicate one field experiment numerically and investigate the effect of different frequencies in the insecticide application in the urban environment. Results The numerical results suggest that the insecticide application has a limited impact on the mosquitoes population and that the optimal application frequency is close to one week. Conclusions Models based on partial differential equations provide an efficient tool for simulating mosquitoes’ spatial population dynamics. The reduced model can reproduce such dynamics on a sufficiently large scale.![]()
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Pinto RDA, Bauzer LGSDR, Borges DT, Lima JBP. Assessing the efficacy of two new formulations of larvicide pyriproxyfen for the control of Aedes aegypti using dissemination stations in two sites of Rio de Janeiro city. Mem Inst Oswaldo Cruz 2020; 115:e200271. [PMID: 33146241 PMCID: PMC7607558 DOI: 10.1590/0074-02760200271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 10/05/2020] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Aedes aegypti is the primary transmitter of several arbovirus with great impact in human health. Controlling vector mosquitoes is an essential and complex task. One promising control method is to use mosquitoes as a vehicle to disseminate tiny particles of juvenile-killing insecticides, such as pyriproxyfen (PPF), to breeding sites. OBJECTIVES We aimed to investigate the capacity of Ae. aegypti to disseminate two new formulations of PPF in two sites of Rio de Janeiro city for assessment of the efficacy of these products. METHODS Dissemination stations impregnated with powder and liquid new formulations of PPF were installed in two test sites. Ovitraps were used in the test sites and in a control site for monitoring the presence of Ae. aegypti throughout eggs collection. FINDINGS Entomological indices indicated that the new formulations of PPF were efficient in reducing eggs abundance. Liquid formulation performed better than powder formulation. Ready-to-use formulations of PPF can be quickly applied in the field and can be replaced after a few months. MAIN CONCLUSIONS New formulations of PPF associated with mosquito dissemination approach make a valuable vector control strategy, managing to cover places of difficult access for whatever reason. New formulations application requires less labour, being economically attractive.
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Affiliation(s)
- Rosilene de Alcântara Pinto
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Fisiologia e Controle de Artrópodes Vetores, Rio de Janeiro, RJ, Brasil.,Prefeitura da Cidade do Rio de Janeiro, Secretaria Municipal de Saúde, Rio de Janeiro, RJ, Brasil
| | - Luiz Guilherme Soares da Rocha Bauzer
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Fisiologia e Controle de Artrópodes Vetores, Rio de Janeiro, RJ, Brasil.,Instituto de Biologia do Exército, Laboratório de Entomologia, Rio de Janeiro, RJ, Brasil
| | | | - José Bento Pereira Lima
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Fisiologia e Controle de Artrópodes Vetores, Rio de Janeiro, RJ, Brasil.,Instituto de Biologia do Exército, Laboratório de Entomologia, Rio de Janeiro, RJ, Brasil
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Parker C. Collection and Rearing of Container Mosquitoes and a 24-h Addition to the CDC Bottle Bioassay. JOURNAL OF INSECT SCIENCE (ONLINE) 2020; 20:13. [PMID: 33135763 PMCID: PMC7751146 DOI: 10.1093/jisesa/ieaa059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Indexed: 06/11/2023]
Abstract
Container mosquitoes (Diptera: Culicidae) oviposit their eggs in both natural and artificial containers. Many container mosquito species also serve as important vectors of disease-causing pathogens including Aedes aegypti, Ae. albopictus, and Ae. triseriatus. Control of these species can be done through the use of adulticide sprays. The efficacy of these treatments is highly dependent on the insecticide susceptibility status of the local mosquito populations. This paper provides protocols on collecting and rearing container mosquitoes for use in the Centers for Disease Control and Prevention (CDC) bottle bioassay. A brief description of the CDC bottle bioassay is provided as well as a standardized protocol for the incorporation of a 24-h mortality to the CDC bottle bioassay. Results from this 24-h holding addition to the CDC bottle bioassay reveal that some forms of resistance may be missed without the incorporation of the additional mortality reading. These protocols provide a foundation for new laboratories to establish rearing protocols and begin conducting resistance monitoring.
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Affiliation(s)
- Casey Parker
- University of Florida, Institute of Food and Agricultural Sciences, Florida Medical Entomology Laboratory, Vero Beach, FL
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23
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Filipović I, Hapuarachchi HC, Tien WP, Razak MABA, Lee C, Tan CH, Devine GJ, Rašić G. Using spatial genetics to quantify mosquito dispersal for control programs. BMC Biol 2020; 18:104. [PMID: 32819378 PMCID: PMC7439557 DOI: 10.1186/s12915-020-00841-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 08/05/2020] [Indexed: 11/10/2022] Open
Abstract
Background Hundreds of millions of people get a mosquito-borne disease every year and nearly one million die. Transmission of these infections is primarily tackled through the control of mosquito vectors. The accurate quantification of mosquito dispersal is critical for the design and optimization of vector control programs, yet the measurement of dispersal using traditional mark-release-recapture (MRR) methods is logistically challenging and often unrepresentative of an insect’s true behavior. Using Aedes aegypti (a major arboviral vector) as a model and two study sites in Singapore, we show how mosquito dispersal can be characterized by the spatial analyses of genetic relatedness among individuals sampled over a short time span without interruption of their natural behaviors. Results Using simple oviposition traps, we captured adult female Ae. aegypti across high-rise apartment blocks and genotyped them using genome-wide SNP markers. We developed a methodology that produces a dispersal kernel for distance which results from one generation of successful breeding (effective dispersal), using the distance separating full siblings and 2nd- and 3rd-degree relatives (close kin). The estimated dispersal distance kernel was exponential (Laplacian), with a mean dispersal distance (and dispersal kernel spread σ) of 45.2 m (95% CI 39.7–51.3 m), and 10% probability of a dispersal > 100 m (95% CI 92–117 m). Our genetically derived estimates matched the parametrized dispersal kernels from previous MRR experiments. If few close kin are captured, a conventional genetic isolation-by-distance analysis can be used, as it can produce σ estimates congruent with the close-kin method if effective population density is accurately estimated. Genetic patch size, estimated by spatial autocorrelation analysis, reflects the spatial extent of the dispersal kernel “tail” that influences, for example, the critical radii of release zones and the speed of Wolbachia spread in mosquito replacement programs. Conclusions We demonstrate that spatial genetics can provide a robust characterization of mosquito dispersal. With the decreasing cost of next-generation sequencing, the production of spatial genetic data is increasingly accessible. Given the challenges of conventional MRR methods, and the importance of quantified dispersal in operational vector control decisions, we recommend genetic-based dispersal characterization as the more desirable means of parameterization.
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Affiliation(s)
- Igor Filipović
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD, 4006, Australia.
| | | | - Wei-Ping Tien
- Environmental Health Institute, National Environment Agency, 11, Biopolis Way, #06-05-08, Singapore, 138667, Singapore
| | | | - Caleb Lee
- Environmental Health Institute, National Environment Agency, 11, Biopolis Way, #06-05-08, Singapore, 138667, Singapore
| | - Cheong Huat Tan
- Environmental Health Institute, National Environment Agency, 11, Biopolis Way, #06-05-08, Singapore, 138667, Singapore
| | - Gregor J Devine
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD, 4006, Australia
| | - Gordana Rašić
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD, 4006, Australia.
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Futami K, Iwashita H, Higa Y, Lutiali PA, Sonye GO, Mwatele C, Njenga SM, Minakawa N. Geographical Distribution of Aedes aegypti aegypti and Aedes aegypti formosus (Diptera: Culicidae) in Kenya and Environmental Factors Related to Their Relative Abundance. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:772-779. [PMID: 31815285 DOI: 10.1093/jme/tjz233] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Indexed: 06/10/2023]
Abstract
The mosquito Aedes aegypti (L.) is the primary vector of various infectious viruses and is typified by a polymorphic color and abundance of white scales on the body. It has been conventionally separated into two subspecies, Ae. aeg. formosus (Walker) (Aaf) and Ae. aeg. aegypti (L.) (Aaa), with Aaf considered a 'sylvan' form and Aaa a 'domestic' form. Because the two subspecies show different susceptibilities to dengue viruses it is important to understand their distribution. In this study, we collected larvae from artificial and natural habitats in southern Kenya and reared them to adults to morphologically identify subspecies. We describe the geographical distribution and relative abundance of Aaa and Aaf in Kenya, and estimate the environmental factors associated with their distributions by GIS using climate and environment data. A total of 5,243 Ae. aegypti adults were collected from 249 sites, with Aaa accounting for 22% of the specimens. The relative abundance of Aaa was higher in coastal areas versus sites in western Kenya. Aaa abundance was also higher in urbanized than forested areas, which is consistent with known ecology. In contrast and inconsistent with previous studies, both Aaa and Aaf were sympatric in artificial and natural habitats. The high relative abundance of Aaa in coastal areas might derive from old populated cities, climate, and/or introduction from abroad.
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Affiliation(s)
- K Futami
- Department of Vector Ecology and Environment, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - H Iwashita
- Department of Vector Ecology and Environment, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
- Department of Bacteriology, Graduate School of Medicine, University of the Ryukyus, Nishiharacho, Okinawa, Japan
| | - Y Higa
- Department of Vector Ecology and Environment, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
- Department of Medical Entomology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - P A Lutiali
- Center for Research in Tropical Medicine and Community Development (CRTMCD), Nairobi, Kenya
| | - G O Sonye
- ASK Community Based Organization located in Mbita, Homabay, Kenya
| | - C Mwatele
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute, Nairobi, Kenya
| | - S M Njenga
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute, Nairobi, Kenya
| | - N Minakawa
- Department of Vector Ecology and Environment, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
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25
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Mwingira VS, Spitzen J, Mboera LEG, Torres-Estrada JL, Takken W. The Influence of Larval Stage and Density on Oviposition Site-Selection Behavior of the Afrotropical Malaria Mosquito Anopheles coluzzii (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:657-666. [PMID: 31630193 PMCID: PMC7197694 DOI: 10.1093/jme/tjz172] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Indexed: 05/26/2023]
Abstract
In the selection of oviposition sites female mosquitoes use various cues to assess site quality to optimize survival of progeny. The presence of conspecific larvae influences this process. Interactive effects of oviposition site selection were studied in the malaria mosquito Anopheles coluzzii Coetzee & Wilkerson in dual- and no-choice assays, by exposing single gravid mosquitoes to oviposition cups containing 1) larvae of different developmental stages, 2) larvae-conditioned water (LCW), and 3) cups where visual cues of conspecific larvae were absent. Early-stage conspecific larvae had a positive effect on the oviposition response. By contrast, late stages of conspecific larvae had a negative effect. Oviposition choice was dependent on larval density. Moreover, in oviposition cups where larvae were hidden from view, late-stage larvae had a significant negative effect on oviposition suggesting the involvement of olfactory cues. LCW had no effect on oviposition response, indicating involvement of chemicals produced by larvae in vivo. It is concluded that the presence of larvae in a breeding site affects the oviposition response depending on the development stage of the larvae. These responses appear to be mediated by olfactory cues emitted by the larval habitat containing live larvae, resulting in the enhanced reproductive fitness of the females.
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Affiliation(s)
| | - Jeroen Spitzen
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
| | - Leonard E G Mboera
- National Institute for Medical Research, Tanga, Tanzania
- Southern African Centre for Infectious Disease Surveillance, Chuo Kikuu, Morogoro, Tanzania
| | - José L Torres-Estrada
- Centro de Investigación de Paludismo, Instituto Nacional de Salud Pública (INSP), Tapachula, Chiapas, México
| | - Willem Takken
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
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26
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Ferreira-de-Lima VH, Andrade PDS, Thomazelli LM, Marrelli MT, Urbinatti PR, Almeida RMMDS, Lima-Camara TN. Silent circulation of dengue virus in Aedes albopictus (Diptera: Culicidae) resulting from natural vertical transmission. Sci Rep 2020; 10:3855. [PMID: 32123282 PMCID: PMC7052239 DOI: 10.1038/s41598-020-60870-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 02/18/2020] [Indexed: 12/04/2022] Open
Abstract
Vertical transmission in Aedes aegypti and Aedes albopictus is considered a maintenance mechanism for dengue virus (DENV) during unfavorable conditions and may be implicated in dengue outbreaks. Since DENV infection dynamics vary among wild-type viruses and vector populations, vertical transmission rates can also vary between regions. However, even though São Paulo is the most populous city in the Americas and has experienced major dengue epidemics, natural vertical transmission had never been detected in this area before. Here we confirm and describe for the first time natural vertical transmission of DENV-3 in two pools of male Ae. albopictus from the city of São Paulo. The detection of DENV-3 in years when no human autochthonous cases of this serotype were recorded suggests that silent circulation of DENV-3 is occurring and indicates that green areas may be maintaining serotypes that are not circulating in the human population, possibly by a vertical transmission mechanism.
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Affiliation(s)
- Victor Henrique Ferreira-de-Lima
- Institute of Tropical Medicine, University of São Paulo. Av. Dr. Enéas de Carvalho Aguiar, 470 - Jardim América, São Paulo, SP, 05403-000, Brazil
| | - Pâmela Dos Santos Andrade
- Department of Epidemiology, School of Public Health, University of São Paulo. Av. Dr. Arnaldo, 715 - Cerqueira César, São Paulo, SP, 01246-904, Brazil
| | - Luciano Matsumiya Thomazelli
- Laboratory of Clinical and Molecular Virology (LVCM), Institute of Biomedical Sciences II, University of São Paulo. Av. Prof. Lineu Prestes, 1374 - Butantã, São Paulo, SP, 05508-900, Brazil
| | - Mauro Toledo Marrelli
- Department of Epidemiology, School of Public Health, University of São Paulo. Av. Dr. Arnaldo, 715 - Cerqueira César, São Paulo, SP, 01246-904, Brazil
| | - Paulo Roberto Urbinatti
- Department of Epidemiology, School of Public Health, University of São Paulo. Av. Dr. Arnaldo, 715 - Cerqueira César, São Paulo, SP, 01246-904, Brazil
| | - Rosa Maria Marques de Sá Almeida
- Department of Epidemiology, School of Public Health, University of São Paulo. Av. Dr. Arnaldo, 715 - Cerqueira César, São Paulo, SP, 01246-904, Brazil
| | - Tamara Nunes Lima-Camara
- Department of Epidemiology, School of Public Health, University of São Paulo. Av. Dr. Arnaldo, 715 - Cerqueira César, São Paulo, SP, 01246-904, Brazil.
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Ovitraps Provide a Reliable Estimate of Wolbachia Frequency during wMelBr Strain Deployment in a Geographically Isolated Aedes aegypti Population. INSECTS 2020; 11:insects11020092. [PMID: 32024068 PMCID: PMC7074419 DOI: 10.3390/insects11020092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 01/08/2023]
Abstract
Deployment of Aedes aegypti mosquitoes carrying the endosymbiont bacterium Wolbachia has been identified as a promising strategy to reduce dengue, chikungunya, and Zika transmission. We investigated whether sampling larvae from ovitraps can provide reliable estimates on Wolbachia frequency during releases, as compared to the expensive adult-based BG-Sentinel. We conducted pilot releases in a semi-field system (SFS) divided into six cages of 21 m2, each with five ovitraps. Five treatments were chosen to represent different points of a hypothetical invasion curve: 10%, 25%, 50%, 75%, and 90% of Wolbachia frequency. Collected eggs were counted and hatched, and the individuals from a net sample of 27% of larvae per treatment were screened for Wolbachia presence by RT-qPCR. Ovitrap positioning had no effect on egg hatching rate. Treatment strongly affected the number of eggs collected and also the hatching rate, especially when Wolbachia was at a 10% frequency. A second observation was done during the release of Wolbachia in Rio under a population replacement approach when bacterium frequency was estimated using 30 BG-Sentinel traps and 45 ovitraps simultaneously. By individually screening 35% (N = 3904) of larvae collected by RT-qPCR, we were able to produce a similar invasion curve to the one observed when all adults were individually screened. If sampling is reduced to 20%, monitoring Wolbachia frequency with 45 ovitraps would be roughly half the cost of screening all adult mosquitoes captured by 30 BG-Sentinels. Our findings support the scale-up of Wolbachia releases, especially in areas with limited resources to afford massive trapping with BG-Sentinel traps.
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28
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Brady OJ, Hay SI. The Global Expansion of Dengue: How Aedes aegypti Mosquitoes Enabled the First Pandemic Arbovirus. ANNUAL REVIEW OF ENTOMOLOGY 2020; 65:191-208. [PMID: 31594415 DOI: 10.1146/annurev-ento-011019-024918] [Citation(s) in RCA: 153] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Dengue is an emerging viral disease principally transmitted by the Aedes (Stegomyia) aegypti mosquito. It is one of the fastest-growing global infectious diseases, with 100-400 million new infections a year, and is now entrenched in a growing number of tropical megacities. Behind this rapid rise is the simple adaptation of Ae. aegypti to a new entomological niche carved out by human habitation. This review describes the expansion of dengue and explores how key changes in the ecology of Ae. aegypti allowed it to become a successful invasive species and highly efficient disease vector. We argue that characterizing geographic heterogeneity in mosquito bionomics will be a key research priority that will enable us to better understand future dengue risk and design control strategies to reverse its global spread.
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Affiliation(s)
- Oliver J Brady
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom;
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Simon I Hay
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington 98121, USA;
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29
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Kroth N, Cozzer GD, de Carvalho G, Cassol AS, Breaux J, Lutinski JA, Busato MA, Roman Junior WA, Dos Santos JJ, Albeny-Simões D. Oviposition preferences of the mosquito Aedes aegypti Linnaeus, 1762 (Culicidae): an urban environment bioassay. BULLETIN OF ENTOMOLOGICAL RESEARCH 2019; 109:762-770. [PMID: 31213206 DOI: 10.1017/s000748531900021x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The establishment of an invasive species depends on reproductive success and dispersion capability in the new environment. One of the striking examples of invasion in urban environments is the mosquito Aedes aegypti Linnaeus, 1762 (Culicidae). The success of this species is primarily attributed to its ability to colonize urban environments, and some of the important adaptive strategies associated with this ability is the preference for humans as a blood source and intense occupation of residential (indoor) environments. This study evaluated the effects of location (indoor vs. outdoor) and water nutrient level (% organic matter) on the oviposition preference of A. aegypti in an urban environment. We used oviposition choice experiments to evaluate mosquito oviposition in containers holding 1:1 vs 1:0 ratios of water: organic matter placed indoors and outdoors. Eggs were sampled once per week for nine weeks. Our results revealed a strong oviposition preference for outdoor containers, with a significant preference for containers with higher concentrations of organic matter during the fifth to ninth weeks. However, mosquitoes occupying indoor environments did not prefer to lay eggs in containers with lower levels of organic matter. A better understanding of the preferences of A. aegypti regarding the nutrient level and location of oviposition containers can increase our understanding of the behavioral factors allowing mosquitoes to utilize anthropogenic environments.
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Affiliation(s)
- N Kroth
- Universidade Comunitária da Região de Chapecó - Programa de Pós Graduação em Ciências Ambientais - Laboratório de Entomologia Ecológica, Chapecó, SC, Brazil
| | - G D Cozzer
- Universidade Comunitária da Região de Chapecó - Curso de Graduação em Ciências Biológicas, Chapecó, SC, Brazil
| | - G de Carvalho
- Universidade Comunitária da Região de Chapecó - Curso de Graduação em Ciências Biológicas, Chapecó, SC, Brazil
| | - A S Cassol
- Universidade Comunitária da Região de Chapecó - Programa de Pós Graduação em Ciências Ambientais - Laboratório de Entomologia Ecológica, Chapecó, SC, Brazil
| | - J Breaux
- New Orleans Mosquito, Termite and Rodent Control Board, 2100 Leon C. Simon Dr - New Orleans, LA 70122, USA
| | - J A Lutinski
- Universidade Comunitária da Região de Chapecó - Programa de Pós Graduação em Ciências da Saúde, Chapecó, SC, Brazil
| | - M A Busato
- Universidade Comunitária da Região de Chapecó - Programa de Pós Graduação em Ciências da Saúde, Chapecó, SC, Brazil
| | - W A Roman Junior
- Universidade Comunitária da Região de Chapecó - Programa de Pós Graduação em Ciências da Saúde, Chapecó, SC, Brazil
| | - José Junior Dos Santos
- Universidade Comunitária da Região de Chapecó - Curso de Graduação em Ciências Biológicas, Chapecó, SC, Brazil
| | - D Albeny-Simões
- Universidade Comunitária da Região de Chapecó - Programa de Pós Graduação em Ciências Ambientais - Laboratório de Entomologia Ecológica, Chapecó, SC, Brazil
- Universidade Comunitária da Região de Chapecó - Curso de Graduação em Ciências Biológicas, Chapecó, SC, Brazil
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30
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Sharma M, Quader S, Guttal V, Isvaran K. The enemy of my enemy: multiple interacting selection pressures lead to unexpected anti-predator responses. Oecologia 2019; 192:1-12. [PMID: 31773313 DOI: 10.1007/s00442-019-04552-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 11/05/2019] [Indexed: 11/26/2022]
Abstract
Despite being a major selective force, predation can induce puzzling variability in anti-predator responses-from lack of predator aversion to lifelong predator-induced fear. This variability is hypothesised to result from variation in the trade-offs associated with avoiding predators. But critical information on fitness outcomes of these trade-offs associated with anti-predator behaviours is lacking. We tested this trade-off hypothesis in Aedes aegypti, by examining oviposition site selection decisions in response towards larval predation risk and comprehensively measuring the fitness implications of trade-offs of avoiding larval predators, using three fitness measures: larval survival, development time and size. In a field study, we find that adult females show a surprisingly variable response to predators, ranging from attraction to avoidance. This variation is explained by fitness outcomes of oviposition along a predation-risk gradient that we measured in the laboratory. We show that ovipositing females could gain fitness benefits from ovipositing in pools with a low density of predators, rather than in predator-free pools, as predators provide a release from negative density effects of conspecific larvae that might co-occur in a pool. Interacting selection pressures may thus explain diverse prey responses. We suggest other systems in which similarly unexpected prey behaviour is likely to occur.
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Affiliation(s)
- Manvi Sharma
- Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, India.
| | | | - Vishwesha Guttal
- Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, India
| | - Kavita Isvaran
- Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, India
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31
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Alonso DP, Campos M, Troca H, Kunii R, Tripet F, Ribolla PEM. Gene expression profile of Aedes aegypti females in courtship and mating. Sci Rep 2019; 9:15492. [PMID: 31664152 PMCID: PMC6820793 DOI: 10.1038/s41598-019-52268-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 10/15/2019] [Indexed: 11/24/2022] Open
Abstract
Aedes aegypti is the most synanthropic and anthropophilic mosquito of Culicidae. This species always cohabits with humans and is extremely opportunistic. Vector dispersal is directly related to the ability of the females on successfully finding a mate in a generally patchy urban scenario. In the present work, we investigate transcriptional changes in Ae. aegypti females during the courtship process and after mating. We observe a substantial alteration in gene expression triggered just upon contact with Ae. aegypti males, which in turn was not fully correlated to the changes triggered by the contact. After analysing shared significant differentially regulated genes between conspecific contact and insemination, the major part of the observed transcriptomic change triggered by contact is reversed after mating, indicating an intermediary situation between naive and mating conditions that we hypothesize to be crucial for mating success. Upon contact, several chemosensory related genes are repressed, especially odorant binding proteins. Most of these genes return to higher expression rates after mating. None of these genes are significantly regulated by the encounter of a different species, Aedes albopictus. The results presented here might be applied to an innovative control approach focusing on the semiochemical systems of mosquitoes in an effort to disrupt undesirable host–insect interaction to reduce the risk of pathogen transmission to humans.
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Affiliation(s)
- Diego Peres Alonso
- Sao Paulo State University - UNESP, Biotechnology Institute and Bioscience Institute, Botucatu, 18618-689, Brazil
| | - Melina Campos
- Sao Paulo State University - UNESP, Biotechnology Institute and Bioscience Institute, Botucatu, 18618-689, Brazil
| | - Heitor Troca
- Sao Paulo State University - UNESP, Biotechnology Institute and Bioscience Institute, Botucatu, 18618-689, Brazil
| | - Rafael Kunii
- Sao Paulo State University - UNESP, Biotechnology Institute and Bioscience Institute, Botucatu, 18618-689, Brazil
| | - Frédéric Tripet
- Keele University, Centre for Applied Entomology and Parasitology, Keele, ST5 5BG, UK
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Parker C, Garcia F, Menocal O, Jeer D, Alto B. A Mosquito Workshop and Community Intervention: A Pilot Education Campaign to Identify Risk Factors Associated with Container Mosquitoes in San Pedro Sula, Honduras. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16132399. [PMID: 31284544 PMCID: PMC6651347 DOI: 10.3390/ijerph16132399] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 01/15/2023]
Abstract
Dengue poses a significant public health threat and results in ~96 million clinical cases every year. Central America is a region burdened by neglected tropical diseases, including dengue. The primary vectors of dengue, Aedes aegypti and Aedes albopictus, are widely distributed in Honduras. Additionally, sustained and consistent mosquito control is lacking in the country. Successful control of container mosquitoes relies heavily on participation from community leaders, stakeholders, and the community itself. We conducted a pilot study in San Pedro Sula, Honduras where community leaders and stakeholders were trained on mosquito biology and control and were able to apply that knowledge to an underserved community in San Pedro Sula. Surveys to assess the number and type of containers in the community and the number of containers on the residence identified associations with select socioeconomic factors and other variables based on survey questions. The average number of containers on the premises was 15 (± 2.3) and the most prevalent containers (>50%) were flowerpots, garbage, and toys, which could be targeted in mosquito control programs. This pilot study offers a framework for training community leaders and stakeholders to create a sustainable community-based vector control program for container mosquitoes.
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Affiliation(s)
- Casey Parker
- Florida Medical Entomology Laboratory, University of Florida, 200 9th St SE, Vero Beach, FL 32962, USA.
| | - Felicita Garcia
- Department of Nursing, Universidad Nacional Autónoma de Honduras-Valle de Sula, 21102 San Pedro Sula, Honduras
| | - Oscar Menocal
- Department of Nursing, Universidad Nacional Autónoma de Honduras-Valle de Sula, 21102 San Pedro Sula, Honduras
| | - Dunia Jeer
- Department of Biology, Universidad Nacional Autónoma de Honduras-Valle de Sula, 21102 San Pedro Sula, Honduras
| | - Barry Alto
- Florida Medical Entomology Laboratory, University of Florida, 200 9th St SE, Vero Beach, FL 32962, USA
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Mysore K, Li P, Wang CW, Hapairai LK, Scheel ND, Realey JS, Sun L, Severson DW, Wei N, Duman-Scheel M. Characterization of a broad-based mosquito yeast interfering RNA larvicide with a conserved target site in mosquito semaphorin-1a genes. Parasit Vectors 2019; 12:256. [PMID: 31118082 PMCID: PMC6532267 DOI: 10.1186/s13071-019-3504-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 05/14/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND RNA interference (RNAi), which has facilitated functional characterization of mosquito neural development genes such as the axon guidance regulator semaphorin-1a (sema1a), could one day be applied as a new means of vector control. Saccharomyces cerevisiae (baker's yeast) may represent an effective interfering RNA expression system that could be used directly for delivery of RNA pesticides to mosquito larvae. Here we describe characterization of a yeast larvicide developed through bioengineering of S. cerevisiae to express a short hairpin RNA (shRNA) targeting a conserved site in mosquito sema1a genes. RESULTS Experiments conducted on Aedes aegypti larvae demonstrated that the yeast larvicide effectively silences sema1a expression, generates severe neural defects, and induces high levels of larval mortality in laboratory, simulated-field, and semi-field experiments. The larvicide was also found to induce high levels of Aedes albopictus, Anopheles gambiae and Culex quinquefasciatus mortality. CONCLUSIONS The results of these studies indicate that use of yeast interfering RNA larvicides targeting mosquito sema1a genes may represent a new biorational tool for mosquito control.
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Affiliation(s)
- Keshava Mysore
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN USA
| | - Ping Li
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN USA
| | - Chien-Wei Wang
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN USA
- Department of Civil and Environmental Engineering and Earth Sciences, The University of Notre Dame, Notre Dame, IN USA
| | - Limb K. Hapairai
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN USA
| | - Nicholas D. Scheel
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN USA
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, IN USA
| | - Jacob S. Realey
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN USA
| | - Longhua Sun
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN USA
| | - David W. Severson
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN USA
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, IN USA
- Department of Life Sciences, The University of the West Indies, St. Augustine, Trinidad, Trinidad and Tobago
| | - Na Wei
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN USA
- Department of Civil and Environmental Engineering and Earth Sciences, The University of Notre Dame, Notre Dame, IN USA
| | - Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN USA
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, IN USA
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Fitzgerald J, Livdahl TP. Vertical Habitat Stratification in Sympatric and Allopatric Populations of Aedes hendersoni and Aedes triseriatus (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:311-319. [PMID: 30668721 DOI: 10.1093/jme/tjy107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Indexed: 06/09/2023]
Abstract
Vertical habitat stratification in populations of Aedes hendersoni Cockerell (Diptera: Culicidae) and Aedes triseriatus (Say) (Diptera: Culicidae) has been observed to varying degrees throughout the species' sympatric range, and potential causes of the phenomenon, including species competition and interaction, have been debated extensively. Stratification patterns in oviposition in allopatric, sympatric, and marginally sympatric populations of both species were investigated and compared in this research to detect any pattern differences related to species composition. Expected patterns were observed in sympatric populations, with Ae. hendersoni preferentially ovipositing in canopy habitats, whereas Ae. triseriatus preferred basal habitats. Allopatric populations presented a strong shift toward basal preference in the former and a slighter but significant shift toward canopy in the latter. Marginal populations of Ae. hendersoni showed intermediate height preferences, whereas preferences of marginal and sympatric Ae. triseriatus did not differ. The convergence of habitat selection in allopatric populations and corresponding divergence in sympatric populations support interspecific competition-based hypotheses regarding the origin of the stratification phenomenon, although plausible alternative or contributing explanations are numerous and warrant further study.
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Oliva LO, La Corte R, Santana MO, Albuquerque CMRD. Quiescence in Aedes aegypti: Interpopulation Differences Contribute to Population Dynamics and Vectorial Capacity. INSECTS 2018; 9:insects9030111. [PMID: 30200417 PMCID: PMC6164356 DOI: 10.3390/insects9030111] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/19/2018] [Accepted: 08/23/2018] [Indexed: 12/03/2022]
Abstract
The strategy of Aedes aegypti to prolong embryonic viability by quiescence has severe implications for geographic expansion and maintenance of mosquito populations in areas under control measures. We evaluated the effects of quiescence on biological parameters directly or indirectly associated with population dynamics and vectorial capacity in populations of this mosquito species from two Brazilian municipalities characterized as dengue, chikungunya, and Zika transmission areas. Egg viability, initial hatching time, post-embryonic development time, adult emergence rate, sexual proportion, adult size, fecundity, and fertility were analyzed using eggs stored for 10, 40, 70, 100, 130, and 160 d. Quiescence time reduced overall egg viability and post-embryonic development time in both municipalities but was more costly in Aracaju (100 d, 8 d) than in Recife (130 d, 7.5 d). Emergence rates increased in Recife when the eggs were older, but not in Aracaju. Significant deviations in sexual proportion, with male predominance, were observed in both populations. Initial hatch, fecundity, fertility, and adult size did not significantly influence egg quiescence time. These results indicate intrinsic and differential characteristics for each A. aegypti population, suggesting a differential cost of quiescence for population dynamics parameters that can indirectly affect vectorial capacity and control measures.
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Affiliation(s)
- Luciana O Oliva
- Departamento de Zoologia, Centro de Biociências, Universidade Federal de Pernambuco (UFPE), Recife 50670-901, Brazil.
- Departamento de Morfologia, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Sergipe (UFS), São Cristóvão 49100-000, Brazil.
| | - Roseli La Corte
- Departamento de Morfologia, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Sergipe (UFS), São Cristóvão 49100-000, Brazil.
| | - Marcelo O Santana
- Departamento de Educação em Saúde, Universidade Federal de Sergipe (UFS), Lagarto 49400-000, Brazil.
| | - Cleide M R de Albuquerque
- Departamento de Zoologia, Centro de Biociências, Universidade Federal de Pernambuco (UFPE), Recife 50670-901, Brazil.
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Gunathilaka N, Ranathunge T, Udayanga L, Wijegunawardena A, Abeyewickreme W. Oviposition preferences of dengue vectors; Aedes aegypti and Aedes albopictus in Sri Lanka under laboratory settings. BULLETIN OF ENTOMOLOGICAL RESEARCH 2018; 108:442-450. [PMID: 28950922 DOI: 10.1017/s0007485317000955] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Investigations on oviposition behaviour of dengue vectors are critical for effective controlling of vector breeding. Therefore, the aim of the present study was to determine the oviposition behaviour of dengue vectors, Aedes aegypti and Aedes albopictus in Sri Lanka. Batches of 1000 adult mosquitoes (1 : 1, male: female ratio) housed in rearing cages were used for each experimental setup from Ae. aegypti and Ae. albopictus. Oviposition responses with respect to the size of the ovitrap, colours of the ovitrap, water source, sodium chloride (NaCl) concentration and presence/absence of larvae were evaluated by enumerating the number of eggs laid in the ovitraps. The analysis of variance and cluster analysis were used to investigate the significance in the variations among oviposition. The number of eggs laid by both species were improved with the increasing size of ovitraps. Ae. albopictus indicated the highest mean number of eggs in 0.2% of NaCl than in the ovitraps filled with distilled water. However, the egg laying preference was reduced with increasing salinity in both species. Drain water with low dissolved oxygen (DO) level (0.43 ± 0.12 mg l-1) was the preferred water source for both species, while a significantly high oviposition rate was observed in ovitraps with larvae. Black colour ovitraps attracted the majority of gravid females, while white was least preferred. There were no significant variations among oviposition behaviours of Ae. albopictus and Ae. aegypti. The ability of these vectors to breed in waste water with low DO levels may lead them to attain wide dissemination in the natural environment, enhancing their potential threat to human life.
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Affiliation(s)
- N Gunathilaka
- Department of Parasitology,Faculty of Medicine,University of Kelaniya,Sri Lanka
| | - T Ranathunge
- Molecular Medicine Unit,Faculty of Medicine,University of Kelaniya,Sri Lanka
| | - L Udayanga
- Molecular Medicine Unit,Faculty of Medicine,University of Kelaniya,Sri Lanka
| | - A Wijegunawardena
- Molecular Medicine Unit,Faculty of Medicine,University of Kelaniya,Sri Lanka
| | - W Abeyewickreme
- C/O, National Research Council funded Dengue Mega Project,Faculty of Medicine,University of Kelaniya,Sri Lanka
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Ruedas G, Peña H, Brisco A, Fujioka KK, Wekesa JW. Life Histories and Other Biological Characteristics Enabling the Establishment of Aedes albopictus in the San Gabriel Valley, California. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2018; 34:93-98. [PMID: 31442161 DOI: 10.2987/17-6699.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Since Aedes albopictus was discovered in 2011 in the San Gabriel Valley it has become widespread despite the "harsh" environmental conditions and intense efforts to control or eliminate it. Species introduced into a new area may survive, thrive, or disappear depending on whether its new environment is suitable. The San Gabriel Valley Mosquito and Vector Control District expended considerable resources from 2011 to 2015 to eradicate this invasive species or, at a minimum, control and manage its spread. Despite the intense effort, the distribution of Ae. albopictus steadily expanded. Over those 5 years this increase shifted from a geometric to exponential pattern. What enabled Ae. albopictus to survive initially, become established, and then expand their distribution when ecological conditions in southern California were considered hostile for this invasive species? This study explores several biological characteristics including skip oviposition, installment egg hatching, and variable larval development that may have helped Ae. albopictus flourish in its new environment.
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38
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Dieng H, Satho T, Suradi NFB, Hakim H, Abang F, Aliasan NE, Miake F, Zuharah WF, Kassim NFA, Majid AHA, Fadzly N, Vargas REM, Morales NP, Noweg GT. Presence of a predator image in potential breeding sites and oviposition responses of a dengue vector. Acta Trop 2017; 176:446-454. [PMID: 28865898 DOI: 10.1016/j.actatropica.2017.08.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 08/11/2017] [Accepted: 08/13/2017] [Indexed: 10/18/2022]
Abstract
In dengue vector control, attempts to minimize or replace the use of pesticides have mostly involved use of predators, but success has been severely impeded by difficulties associated with financial and environmental costs, predator mass production, and persistence in target habitats. Visual deterrents have been used successfully to control animal pests, in some cases in an effort to replace pesticide use. Despite evidence that visual signals are crucial in site choice for egg deposition by dengue vectors, and that female mosquitoes respond to artificial predation, the role of predator intimidation as it affects the oviposition behavior of dengue vectors remains largely unexplored. Here, we examined the oviposition responses of Aedes aegypti exposed to various mosquito predator pictures. Gravid females were presented with equal opportunities to oviposit in two cups with predator images [Toxorhynchites splendens-TXI, Goldfish (Carassius auratus)-small (SFI) and large (LFI) and Tx. splendens+Goldfish-TXFI] and two others without pictures. Differences in egg deposition were examined between sites with and without these images. When given a chance to oviposit in cups with and without TXI, Ae. aegypti females were similarly attracted to both sites. When provided an opportunity to oviposit in cups displaying pictures of fish (SFI or LFI) and blank cups, egg deposition rates were much lower in the fish picture sites. Females showed a preference for blank cups over TXFI for egg deposition. They also equally avoided cups with pictures of fish, regardless of the size of the picture. Our results indicate that the presence of images of goldfish and their association with Tx. larvae significantly reduced egg deposition by Ae. aegypti, and this was not the case with the predatory larvae alone. The observations that the images of natural predators can repel gravid females of a dengue vector provide novel possibilities to develop effective and inexpensive alternative tools to harmful insecticides.
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39
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Johnson BJ, Ritchie SA, Fonseca DM. The State of the Art of Lethal Oviposition Trap-Based Mass Interventions for Arboviral Control. INSECTS 2017; 8:insects8010005. [PMID: 28075354 PMCID: PMC5371933 DOI: 10.3390/insects8010005] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/15/2016] [Accepted: 12/19/2016] [Indexed: 12/24/2022]
Abstract
The intensifying expansion of arboviruses highlights the need for effective invasive Aedes control. While mass-trapping interventions have long been discredited as inefficient compared to insecticide applications, increasing levels of insecticide resistance, and the development of simple affordable traps that target and kill gravid female mosquitoes, show great promise. We summarize the methodologies and outcomes of recent lethal oviposition trap-based mass interventions for suppression of urban Aedes and their associated diseases. The evidence supports the recommendation of mass deployments of oviposition traps to suppress populations of invasive Aedes, although better measures of the effects on disease control are needed. Strategies associated with successful mass-trap deployments include: (1) high coverage (>80%) of the residential areas; (2) pre-intervention and/or parallel source reduction campaigns; (3) direct involvement of community members for economic long-term sustainability; and (4) use of new-generation larger traps (Autocidal Gravid Ovitrap, AGO; Gravid Aedes Trap, GAT) to outcompete remaining water-holding containers. While to the best of our knowledge all published studies so far have been on Ae. aegypti in resource-poor or tropical settings, we propose that mass deployment of lethal oviposition traps can be used for focused cost-effective control of temperate Ae. albopictus pre-empting arboviral epidemics and increasing participation of residents in urban mosquito control.
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Affiliation(s)
- Brian J Johnson
- College of Public Health, Medical and Veterinary Sciences, James Cook University, McGregor Rd., Cairns, QLD 4878, Australia.
- Australian Institute of Tropical Health and Medicine, James Cook University, P.O. Box 6811, Cairns, QLD 4870, Australia.
| | - Scott A Ritchie
- College of Public Health, Medical and Veterinary Sciences, James Cook University, McGregor Rd., Cairns, QLD 4878, Australia.
- Australian Institute of Tropical Health and Medicine, James Cook University, P.O. Box 6811, Cairns, QLD 4870, Australia.
| | - Dina M Fonseca
- Center for Vector Biology, Rutgers University, 180 Jones Ave., New Brunswick, NJ 08901, USA.
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40
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Chitolina RF, Anjos FA, Lima TS, Castro EA, Costa-Ribeiro MCV. Raw sewage as breeding site to Aedes (Stegomyia) aegypti (Diptera, culicidae). Acta Trop 2016; 164:290-296. [PMID: 27640323 DOI: 10.1016/j.actatropica.2016.07.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 06/28/2016] [Accepted: 07/17/2016] [Indexed: 12/15/2022]
Abstract
The selection of oviposition sites by females of Aedes (Stegomyia) aegypti is a key factor for the larval survival and egg dispersion and has a direct influence in vector control programs. In this study, we evaluated the aspects of reproductive physiology of Ae. aegypti mosquitoes tested in the presence of raw sewage. Ae. aegypti females were used in oviposition bioassays according to two methodologies: (i) choice assay, in which three oviposition substrates were offered in the same cage: treatment (raw sewage), positive control (distilled water) and negative control (1% sodium hypochlorite) and; (ii) no choice assay, in which only one substrate was available. The physicochemical and microbiological analysis of the raw sewage used in this study indicated virtually no levels of chlorine, low levels of dissolved oxygen and high levels of nitrogenous compounds as well as the presence of Escherichia coli and total fecal coliforms. After 72h of oviposition, the eggs were counted and there was no statistically significant difference (p>0.05) in the oviposition rate between raw sewage and positive control in both methodologies. In addition, females were dissected to evaluate egg-retention and also there were no appreciable differences in egg retention even when raw sewage was the only substrate offered. The data also showed that egg hatching and larvae development occurred normally in the raw sewage. Therefore, the present study suggests that Ae. aegypti can adapt to new sites and lay eggs in polluted water, such as the raw sewage. These findings are of particular importance for the control and surveillance programs against Ae. aegypti in countries where the conditions of poor infrastructure and lack of basic sanitation are still an issue.
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Affiliation(s)
- R F Chitolina
- Laboratório de Parasitologia Molecular, Departamento de Patologia Básica, Centro Politécnico, Universidade Federal do Paraná, Brazil
| | - F A Anjos
- Laboratório de Parasitologia Molecular, Departamento de Patologia Básica, Centro Politécnico, Universidade Federal do Paraná, Brazil
| | - T S Lima
- Laboratório de Parasitologia Molecular, Departamento de Patologia Básica, Centro Politécnico, Universidade Federal do Paraná, Brazil
| | - E A Castro
- Laboratório de Parasitologia Molecular, Departamento de Patologia Básica, Centro Politécnico, Universidade Federal do Paraná, Brazil
| | - M C V Costa-Ribeiro
- Laboratório de Parasitologia Molecular, Departamento de Patologia Básica, Centro Politécnico, Universidade Federal do Paraná, Brazil.
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Choi DB, Grieco JP, Apperson CS, Schal C, Ponnusamy L, Wesson DM, Achee NL. Effect of Spatial Repellent Exposure on Dengue Vector Attraction to Oviposition Sites. PLoS Negl Trop Dis 2016; 10:e0004850. [PMID: 27428011 PMCID: PMC4948784 DOI: 10.1371/journal.pntd.0004850] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 06/24/2016] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Aedes aegypti is a primary vector of dengue virus (DENV), the causative agent of dengue fever, an arthropod-borne disease of global importance. Although a vaccine has been recommended for prevention, current dengue prevention strategies rely on vector control. Recently, volatile pyrethroids-spatial repellents-have received interest as a novel delivery system for adult Ae. aegypti control. Understanding the full range of behavioral effects spatial repellents elicit in mosquito species will be critical to understanding the overall impact these products have on vector populations and will guide expectations of efficacy against DENV transmission. METHODOLOGY/PRINCIPAL FINDINGS The current study quantified changes in attraction of gravid Ae. aegypti to experimental oviposition sites following exposure to the spatial repellent transfluthrin. Responses were measured with two-choice olfaction bioassays using 'sticky-screens' covering cups to prevent contact with the oviposition substrate. Two cups contained a bacterial attractant composed of four species of bacteria in calcium alginate beads in water and two cups contained only deionized water. Results from 40 replicates (n = 780 females total per treatment) indicated an estimated difference in attraction of 9.35% ± 0.18 (p ≤ 0.003), implying that the transfluthrin-exposed mosquitoes were more attracted to the experimental oviposition sites than the non-exposed mosquitoes. CONCLUSIONS/SIGNIFICANCE Findings from this study will further characterize the role of spatial repellents to modify Ae. aegypti behavior related to dengue prevention specifically, and encourage innovation in vector control product development more broadly.
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Affiliation(s)
- Diane B. Choi
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - John P. Grieco
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Charles S. Apperson
- Department of Entomology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Coby Schal
- Department of Entomology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Loganathan Ponnusamy
- Department of Entomology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Dawn M. Wesson
- Department of Tropical Medicine, Tulane University, New Orleans, Louisiana, United States of America
| | - Nicole L. Achee
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
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Axford JK, Ross PA, Yeap HL, Callahan AG, Hoffmann AA. Fitness of wAlbB Wolbachia Infection in Aedes aegypti: Parameter Estimates in an Outcrossed Background and Potential for Population Invasion. Am J Trop Med Hyg 2015; 94:507-16. [PMID: 26711515 DOI: 10.4269/ajtmh.15-0608] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 11/03/2015] [Indexed: 11/07/2022] Open
Abstract
Wolbachia endosymbionts are potentially useful tools for suppressing disease transmission by Aedes aegypti mosquitoes because Wolbachia can interfere with the transmission of dengue and other viruses as well as causing deleterious effects on their mosquito hosts. Most recent research has focused on the wMel infection, but other infections also influence viral transmission and may spread in natural populations. Here, we focus on the wAlbB infection in an Australian outbred background and show that this infection has many features that facilitate its invasion into natural populations including strong cytoplasmic incompatibility, a lack of effect on larval development, an equivalent mating success to uninfected males and perfect maternal transmission fidelity. On the other hand, the infection has deleterious effects when eggs are held in a dried state, falling between wMel and the more virulent wMelPop Wolbachia strains. The impact of this infection on lifespan also appears to be intermediate, consistent with the observation that this infection has a titer in adults between wMel and wMelPop. Population cage experiments indicate that the wAlbB infection establishes in cages when introduced at a frequency of 22%, suggesting that this strain could be successfully introduced into populations and subsequently persist and spread.
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Affiliation(s)
- Jason K Axford
- Pest and Environmental Adaptation Research Group, Bio21 Institute and School of BioSciences, University of Melbourne, Parkville, Australia; Commonwealth Scientific and Industrial Research Organization, Acton, Australia
| | - Perran A Ross
- Pest and Environmental Adaptation Research Group, Bio21 Institute and School of BioSciences, University of Melbourne, Parkville, Australia; Commonwealth Scientific and Industrial Research Organization, Acton, Australia
| | - Heng Lin Yeap
- Pest and Environmental Adaptation Research Group, Bio21 Institute and School of BioSciences, University of Melbourne, Parkville, Australia; Commonwealth Scientific and Industrial Research Organization, Acton, Australia
| | - Ashley G Callahan
- Pest and Environmental Adaptation Research Group, Bio21 Institute and School of BioSciences, University of Melbourne, Parkville, Australia; Commonwealth Scientific and Industrial Research Organization, Acton, Australia
| | - Ary A Hoffmann
- Pest and Environmental Adaptation Research Group, Bio21 Institute and School of BioSciences, University of Melbourne, Parkville, Australia; Commonwealth Scientific and Industrial Research Organization, Acton, Australia
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Davis TJ, Kaufman PE, Hogsette JA, Kline DL. The Effects of Larval Habitat Quality on Aedes albopictus Skip Oviposition. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2015; 31:321-328. [PMID: 26675453 DOI: 10.2987/moco-31-04-321-328.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Aedes albopictus is an invasive mosquito species that transmits human-disease-causing pathogens. It is a container-inhabiting species that oviposits in resource-limited habitats. To mitigate larval competition, Ae. albopictus females may choose to distribute eggs from a single gonotrophic cycle among multiple containers through skip oviposition. With the use of individual females released in indoor and outdoor caged trials, we evaluated the oviposition choices made by gravid Ae. albopictus offered larval habitats with different qualities. Our results demonstrate that Ae. albopictus performs skip oviposition and that the degree of egg distribution is related to the quality of the larval habitat. In a 4-choice arena, individual Ae. albopictus oviposited in fewer containers when presented with ovisites of high-quality larval habitat (uncrowded conditions) compared with oviposition in low-quality (crowded conditions) larval habitats. Additionally, the females selectively oviposited in high-quality habitats when offered both low- and high-quality habitats, but distributed eggs more evenly among multiple high-quality habitats. Our results have important implications for mosquito management plans that include the use of lethal ovitraps, as well as the role of this behavior in distribution of disease-causing pathogens.
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Affiliation(s)
- Timothy J Davis
- 1 Entomology and Nematology Department, PO Box 110620, University of Florida, Gainesville, FL 32611
| | - Phillip E Kaufman
- 1 Entomology and Nematology Department, PO Box 110620, University of Florida, Gainesville, FL 32611
| | - Jerome A Hogsette
- 2 US Department of Agriculture-Agricultural Research Service, Center for Medical, Agricultural and Veterinary Entomology, 1600 SW 23rd Drive, Gainesville, FL 32608
| | - Daniel L Kline
- 2 US Department of Agriculture-Agricultural Research Service, Center for Medical, Agricultural and Veterinary Entomology, 1600 SW 23rd Drive, Gainesville, FL 32608
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Abreu FVSD, Morais MM, Ribeiro SP, Eiras ÁE. Influence of breeding site availability on the oviposition behaviour of Aedes aegypti. Mem Inst Oswaldo Cruz 2015; 110:669-76. [PMID: 26154742 PMCID: PMC4569832 DOI: 10.1590/0074-02760140490] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 06/03/2015] [Indexed: 11/22/2022] Open
Abstract
Despite the importance of the mosquito Aedes aegypti in the
transmission of arboviruses, such as yellow fever, Chikungunya fever and dengue
fever, some aspects of their behaviour remain unknown. In the present study, the
oviposition behaviour of Ae. aegypti females that were exposed to
different densities of breeding sites (2, 4, 8 and 16) was evaluated in laboratory
and semi-field conditions. The number of breeding sites that were used was
proportional to the number available, but tended towards stabilisation. Females used
four-six breeding sites on average, with a maximum of 11. A high percentage of eggs
was observed in the water, along with the presence of a breeding site termed
“favourite”, which received at least 40% of the eggs. The results are discussed in
ecological, evolutionary and epidemiological approaches.
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Affiliation(s)
- Filipe Vieira Santos de Abreu
- Laboratório de Estudos de Comportamento do Aedes aegypti, Instituto Federal do Norte de Minas Gerais, Salinas, MG, BR
| | | | - Sérvio Pontes Ribeiro
- Laboratório de Ecologia Evolutiva de Insetos de Dossel e Sucessão Natural, Universidade Federal de Ouro Preto, Ouro Preto, MG, BR
| | - Álvaro Eduardo Eiras
- Laboratório de Ecologia Química de Vetores, Universidade Federal de Minas Gerais, Belo Horizonte, MG, BR
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Sayson SL, Gloria-Soria A, Powell JR, Edillo FE. Seasonal Genetic Changes of Aedes aegypti (Diptera: Culicidae) Populations in Selected Sites of Cebu City, Philippines. JOURNAL OF MEDICAL ENTOMOLOGY 2015; 52:638-46. [PMID: 26335470 PMCID: PMC4592349 DOI: 10.1093/jme/tjv056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 04/21/2015] [Indexed: 05/26/2023]
Abstract
Aedes aegypti (L.) is the primary vector of dengue virus in the Philippines, where dengue is endemic. We examined the genetic changes of Ae. aegypti collected from three selected sites in Cebu city, Philippines, during the relatively wet (2011-2012) and dry seasons (2012 and 2013). A total of 493 Ae. aegypti adults, reared in the laboratory from field-collected larvae, were analyzed using 11 microsatellite loci. Seasonal variation was observed in allele frequencies and allelic richness. Average genetic differentiation (DEST=0.018; FST=0.029) in both dry seasons was higher, due to reduced Ne, than in the wet season (DEST=0.006; FST=0.009). Thus, average gene flow was higher in the wet season than in the dry seasons. However, the overall FST estimate (0.02) inclusive of the two seasons showed little genetic differentiation as supported by Bayesian clustering analysis. Results suggest that during the dry season the intense selection that causes a dramatic reduction of population size favors heterozygotes, leading to small pockets of mosquitoes (refuges) that exhibit random genetic differentiation. During the wet season, the genetic composition of the population is reconstituted by the expansion of the refuges that survived the preceding dry season. Source reduction of mosquitoes during the nonepidemic dry season is thus recommended to prevent dengue re-emergence in the subsequent wet season.
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Affiliation(s)
- S L Sayson
- Department of Biology, University of San Carlos - Talamban Campus, Talamban, Cebu City, Philippines 6000.
| | - A Gloria-Soria
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511
| | - J R Powell
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511
| | - F E Edillo
- Department of Biology, University of San Carlos - Talamban Campus, Talamban, Cebu City, Philippines 6000
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Fonzi E, Higa Y, Bertuso AG, Futami K, Minakawa N. Human-Mediated Marine Dispersal Influences the Population Structure of Aedes aegypti in the Philippine Archipelago. PLoS Negl Trop Dis 2015; 9:e0003829. [PMID: 26039311 PMCID: PMC4454683 DOI: 10.1371/journal.pntd.0003829] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/14/2015] [Indexed: 11/22/2022] Open
Abstract
Background Dengue virus (DENV) is an extraordinary health burden on global scale, but still lacks effective vaccine. The Philippines is endemic for dengue fever, but massive employment of insecticides favored the development of resistance mutations in its major vector, Aedes aegypti. Alternative vector control strategies consist in releasing artificially modified mosquitos in the wild, but knowledge on their dispersal ability is necessary for a successful implementation. Despite being documented that Ae. aegypti can be passively transported for long distances, no study to date has been aimed at understanding whether human marine transportation can substantially shape the migration patterns of this mosquito. With thousands of islands connected by a dense network of ships, the Philippines is an ideal environment to fill this knowledge gap. Methodology/principal findings Larvae of Ae. aegypti from 15 seaports in seven major islands of central-western Philippines were collected and genotyped at seven microsatellite loci. Low genetic structure and considerable gene flow was found in the area. Univariate and multivariate regression analyses suggested that anthropic factors (specifically the amount of processed cargo and human population density) can explain the observed population structure, while geographical distance was not correlated. Interestingly, cargo shipments seem to be more efficient than passenger ships in transporting Ae. aegypti. Bayesian clustering confirmed that Ae. aegypti from busy ports are more genetically similar, while populations from idle ports are relatively structured, regardless of the geographical distance that separates them. Conclusions/significance The results confirmed the pivotal role of marine human-mediated long-range dispersal in determining the population structure of Ae. aegypti. Hopefully corroborated by further research, the present findings could assist the design of more effective vector control strategies. Dengue fever threatens the health of millions in the tropics and its causative agent, dengue virus, is mainly transmitted by the mosquito Aedes aegypti. To control the spread of the virus, insecticides have been abundantly used but Ae. aegypti has developed a genetic resistance to them. Currently, alternative methods are being tested wherein artificially modified mosquitos are released in the wild to interfere with the mating of natural populations. It is important then to understand how the mosquito spreads in the environment. It is known that Ae. aegytpi can be passively transported for long distances by human vehicles, but it was not clear how common this event is, especially in case of marine transportation. In population genetics, a basic assumption says that if populations frequently exchange migrants, they become genetically more similar than relatively isolated populations. We estimated the genetic similarity between Ae. aegypti collected in the Philippines from 15 seaports of different sizes and ship connectivity. The mosquitos from busy ports, even distant ones, were genetically similar, while in the small ports, even close ones, Ae. aegypti were relatively differentiated. It was also suggested that Ae. aegypti's dispersal is affected by cargo shipments more than passenger ships.
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Affiliation(s)
- Eugenio Fonzi
- Department of Vector Ecology and Environment, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
- * E-mail:
| | - Yukiko Higa
- Department of Vector Ecology and Environment, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Arlene G. Bertuso
- Department of Public Health, University of the Philippines, Manila, Philippines
| | - Kyoko Futami
- Department of Vector Ecology and Environment, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Noboru Minakawa
- Department of Vector Ecology and Environment, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
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Abad-Franch F, Zamora-Perea E, Ferraz G, Padilla-Torres SD, Luz SLB. Mosquito-disseminated pyriproxyfen yields high breeding-site coverage and boosts juvenile mosquito mortality at the neighborhood scale. PLoS Negl Trop Dis 2015; 9:e0003702. [PMID: 25849040 PMCID: PMC4388722 DOI: 10.1371/journal.pntd.0003702] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 03/13/2015] [Indexed: 11/18/2022] Open
Abstract
Background Mosquito-borne pathogens pose major public health challenges worldwide. With vaccines or effective drugs still unavailable for most such pathogens, disease prevention heavily relies on vector control. To date, however, mosquito control has proven difficult, with low breeding-site coverage during control campaigns identified as a major drawback. A novel tactic exploits the egg-laying behavior of mosquitoes to have them disseminate tiny particles of a potent larvicide, pyriproxyfen (PPF), from resting to breeding sites, thus improving coverage. This approach has yielded promising results at small spatial scales, but its wider applicability remains unclear. Methodology/Principal Findings We conducted a four-month trial within a 20-month study to investigate mosquito-driven dissemination of PPF dust-particles from 100 ‘dissemination stations’ (DSs) deployed in a 7-ha sub-area to surveillance dwellings and sentinel breeding sites (SBSs) distributed over an urban neighborhood of about 50 ha. We assessed the impact of the trial by measuring juvenile mosquito mortality and adult mosquito emergence in each SBS-month. Using data from 1,075 dwelling-months, 2,988 SBS-months, and 29,922 individual mosquitoes, we show that mosquito-disseminated PPF yielded high coverage of dwellings (up to 100%) and SBSs (up to 94.3%). Juvenile mosquito mortality in SBSs (about 4% at baseline) increased by over one order of magnitude during PPF dissemination (about 75%). This led to a >10-fold decrease of adult mosquito emergence from SBSs, from approximately 1,000–3,000 adults/month before to about 100 adults/month during PPF dissemination. Conclusions/Significance By expanding breeding-site coverage and boosting juvenile mosquito mortality, a strategy based on mosquito-disseminated PPF has potential to substantially enhance mosquito control. Sharp declines in adult mosquito emergence can lower vector/host ratios, reducing the risk of disease outbreaks. This approach is a very promising complement to current and novel mosquito control strategies; it will probably be especially relevant for the control of urban disease vectors, such as Aedes and Culex species, that often cause large epidemics. Mosquito-transmitted diseases are among the most challenging infectious threats worldwide. Mosquito control is crucial for preventing infection and disease, particularly when effective vaccines or drugs are unavailable. A major drawback of current mosquito control strategies is that mosquito breeding sites are often overlooked, and therefore left untreated, during control campaigns. One appealing alternative proposes exploiting the innate breeding-site–finding ability of female mosquitoes to have them disseminate tiny insecticide particles that poison their offspring. Thus far, however, this idea has only been tested in small-scale trials. Here we show that mosquitoes effectively transferred insecticide particles from dissemination stations to sentinel breeding sites over distances between 3 and 400 m in a tropical urban neighborhood. This yielded high breeding-site coverage, with up to 94.3% of sentinel breeding sites presenting evidence of contamination with mosquito-disseminated insecticide. We recorded a 10-fold increase of juvenile mosquito mortality and a 10-fold decrease of adult mosquito emergence during the four-month dissemination trial. In combination with other tactics, this approach has the potential to considerably enhance mosquito-borne disease prevention, particularly in urban settings.
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Affiliation(s)
- Fernando Abad-Franch
- Laboratório de Ecologia de Doenças Transmissíveis na Amazônia, Instituto Leônidas e Maria Deane—Fiocruz Amazônia, Manaus, Brazil
- * E-mail:
| | - Elvira Zamora-Perea
- Laboratório de Ecologia de Doenças Transmissíveis na Amazônia, Instituto Leônidas e Maria Deane—Fiocruz Amazônia, Manaus, Brazil
| | - Gonçalo Ferraz
- Departamento de Ecologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Biological Dynamics of Forest Fragments Project, Smithsonian Tropical Research Institute/Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
| | - Samael D. Padilla-Torres
- Laboratório de Ecologia de Doenças Transmissíveis na Amazônia, Instituto Leônidas e Maria Deane—Fiocruz Amazônia, Manaus, Brazil
| | - Sérgio L. B. Luz
- Laboratório de Ecologia de Doenças Transmissíveis na Amazônia, Instituto Leônidas e Maria Deane—Fiocruz Amazônia, Manaus, Brazil
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Ong SQ, Jaal Z. Investigation of mosquito oviposition pheromone as lethal lure for the control of Aedes aegypti (L.) (Diptera: Culicidae). Parasit Vectors 2015; 8:28. [PMID: 25588346 PMCID: PMC4299678 DOI: 10.1186/s13071-015-0639-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/02/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The trend in chemical insecticide development has focused on improving the efficacy against mosquitoes while reducing the environmental impact. Lethal lures apply an "attract-and-kill" strategy that draws the insect to the killing agent rather than bringing the killing agent to the insect. METHODS In this study, the mosquito oviposition pheromone was extracted from the eggs of Aedes aegypti (L.) and further investigated with a combination of pheromone and granular temephos as a lethal lure. RESULTS The compound caproic acid attracted significantly more egg-laying mosquitos at 1 ppm (660.83 ± 91.61) than the control (343.83 ± 56.24), which consisted of solvent only (Oviposition Activity Index: 0.316). Further investigation of the combination of caproic acid with granular temephos as a lethal lure attracted significantly more gravid female Ae. aegypti to oviposit their eggs than the temephos treated water and control. CONCLUSIONS This indicated the ability of caproic acid in acting as an attractant and counters the repellency effect of temephos. Additionally, the presence of temephos in the lethal lure also restricted the hatching of the eggs and killed any larvae that hatched.
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Affiliation(s)
- Song-Quan Ong
- Vector Control Research Unit, School of Biological Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia.
| | - Zairi Jaal
- Vector Control Research Unit, School of Biological Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia.
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Anderson EM, Davis JA. Field evaluation of the response of Aedes albopictus (Stegomyia albopicta) to three oviposition attractants and different ovitrap placements using black and clear autocidal ovitraps in a rural area of Same, Timor-Leste. MEDICAL AND VETERINARY ENTOMOLOGY 2014; 28:372-383. [PMID: 24805793 DOI: 10.1111/mve.12062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 01/26/2014] [Accepted: 01/31/2014] [Indexed: 06/03/2023]
Abstract
Known oviposition attractants or stimulants were compared, singly and in combination, using inexpensive autocidal ovitraps designed to trap emerging adults, in a rural area of Timor-Leste during the dry season. In this area, the dengue vector Aedes albopictus (Stegomyia albopicta) Skuse (Diptera: Culicidae) was abundant, but Aedes aegypti (Stegomyia aegypti) L. was not detected. The attractants were: (a) a compound found in Aedes eggs (dodecanoic acid); (b) components of nitrogen, phosphorous and potassium-based (NPK) fertilizer, and (c) infusions of discarded cigarette butts. A solution of ammonium phosphate and potassium nitrate was significantly more attractive to gravid Ae. albopictus than water only. Dodecanoic acid and cigarette butt infusions were not significantly more attractive than the control; however, they attracted various other Diptera and many non-culicid larvae developed in ovitraps in which these substances were used; thus, the presence of eggs or larvae of other species may have deterred Aedes oviposition. Significantly more Aedes eggs were found in ovitraps under vegetation than in ovitraps placed inside houses or against external walls. Clear-sided ovitraps in which black mesh was placed over a black ring floating on the water surface collected significantly fewer eggs than black ovitraps with identically placed mesh and rings.
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Affiliation(s)
- E M Anderson
- Department of Biological Sciences, Monash University, Clayton, Vic, Australia
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50
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Hoffmann AA, Goundar AA, Long SA, Johnson PH, Ritchie SA. Invasion of Wolbachia at the residential block level is associated with local abundance of Stegomyia aegypti, yellow fever mosquito, populations and property attributes. MEDICAL AND VETERINARY ENTOMOLOGY 2014; 28 Suppl 1:90-97. [PMID: 25171611 DOI: 10.1111/mve.12077] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Revised: 02/28/2014] [Accepted: 03/17/2014] [Indexed: 06/03/2023]
Abstract
Wolbachia can suppress dengue and control mosquito populations and this depends on the successful invasion of Wolbachia-infected mosquitoes into local populations. Ovitrap data collected during the recent invasion of wMel-infected Stegomyia aegypti (Diptera: Culicidae) (Linnaeus) into Gordonvale near Cairns, Australia, were used to identify variables that help predict the success of localized invasion. Based on the variance in Wolbachia frequencies across Gordonvale as well as at another release site at Yorkeys Knob in comparison to simulations, it was estimated that on average 2-4 females contributed eggs to an ovitrap. By collating ovitrap data from two collection periods at the start of the release from residential blocks, it was found that uninfected mosquitoes had a patchy distribution across the release site. Residential blocks with relatively high uninfected mosquito numbers were less easily invaded by Wolbachia than blocks with low numbers. The numbers of uninfected mosquitoes in ovitraps were negatively correlated with the proportion of brick houses in a residential block, whereas local Wolbachia frequencies were correlated positively with this variable as well as negatively with the amount of shading in a yard and availability of breeding sites. These findings point to proxy measures for predicting the ease of localized invasion of Wolbachia.
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Affiliation(s)
- A A Hoffmann
- Pest and Disease Vector Group, Department of Genetics, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
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