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Sahavechaphan N, Chatrattikorn A, Rattananen M, Sadakorn P, Areechokchai D, Iamsirithaworn S. Identifying villages and breeding habitats for dengue transmission in Thailand: insights from long-term larval surveys. BMC Infect Dis 2024; 24:523. [PMID: 38789932 PMCID: PMC11119398 DOI: 10.1186/s12879-024-09398-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
BACKGROUND In Thailand, the Department of Disease Control (DDC) regularly performs visual larval surveys throughout the country to monitor dengue fever outbreaks. Since 2016, the DDC switched from a paper-based to a digital-based larval survey process. The significant amount of larval survey data collected digitally presents a valuable opportunity to precisely identify the villages and breeding habitats that are vulnerable to dengue transmission. METHODS The study used digitally collected larval survey data from 2017 to 2019. It employed larval indices to evaluate the risk of dengue transmission in villages based on seasonal, regional, and categorical perspectives. Furthermore, the study comprehensively scrutinized each container category by employing different measures to determine its breeding preference ratio. RESULTS The result showed that villages with a very high-risk of dengue transmission were present year-round in all regions, with the highest proportion during the rainy season. The Southern region had more high-risk villages during the winter season due to rainfall. Slums and residential communities were more vulnerable to dengue than commercial areas. All container categories could potentially serve as breeding habitats for dengue-carrying mosquitoes, with abandoned containers being the most significant breeding sites. CONCLUSIONS The risk of dengue transmission was present year-round throughout Thailand. This underscores the importance of community and government initiatives, along with sustained public awareness campaigns and active community engagement, to efficiently and permanently eradicate mosquito breeding habitats. It should be noted that larval indices may not strongly correlate with dengue cases, as indicated by the preliminary analysis. However, they offer valuable insights into potential breeding sites for targeted preventive measures.
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Affiliation(s)
- Naiyana Sahavechaphan
- National Electronics and Computer Technology Center, National Science and Technology Development Agency, 112 Thailand Science Park, Phahonyothin Road, 12120, Pathum Thani, Thailand.
| | - Asamaporn Chatrattikorn
- National Electronics and Computer Technology Center, National Science and Technology Development Agency, 112 Thailand Science Park, Phahonyothin Road, 12120, Pathum Thani, Thailand
| | - Manot Rattananen
- National Electronics and Computer Technology Center, National Science and Technology Development Agency, 112 Thailand Science Park, Phahonyothin Road, 12120, Pathum Thani, Thailand
| | - Pongsakorn Sadakorn
- Department of Disease Control, Ministry of Public Health, 88/21 Tawanon Road, 11000, Nonthaburi, Thailand
| | - Darin Areechokchai
- Department of Disease Control, Ministry of Public Health, 88/21 Tawanon Road, 11000, Nonthaburi, Thailand
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Mwakutwaa AS, Ngugi HN, Ndenga BA, Krystosik A, Ngari M, Abubakar LU, Yonge S, Kitron U, LaBeaud AD, Mutuku FM. Pupal productivity of larval habitats of Aedes aegypti in Msambweni, Kwale County, Kenya. Parasitol Res 2023; 122:801-814. [PMID: 36683088 PMCID: PMC9988718 DOI: 10.1007/s00436-022-07777-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 12/30/2022] [Indexed: 01/24/2023]
Abstract
Aedes aegypti is an important vector of several arboviruses including dengue and chikungunya viruses. Accurate identification of larval habitats of Ae. aegypti is considered an essential step in targeted control. This study determined Ae. aegypti productivity in selected larval habitats in Msambweni, Kwale County, Kenya. Three sequential larval habitat surveys were conducted. The first survey was habitat census (baseline) through which 83 representative larval habitats were identified and selected. The second and third surveys involved estimating daily productivity of the 83 selected larval habitats for 30 consecutive days during a wet and a dry season, respectively. Of 664 larval habitats examined at baseline, 144 larval habitats (21.7%) were found to be infested with Ae. aegypti larvae. At baseline, majority (71%) of the pupae were collected from two (2/6) larval habitat types, tires and pots. Multivariate analysis identified habitat type and the habitat being movable as the predictors for pupal abundance. During the 30-day daily pupal production surveys, only a few of the habitats harbored pupae persistently. Pupae were found in 28% and 12% of the larval habitats during the wet and dry seasons, respectively. In the wet season, drums, tires, and pots were identified as the key habitat types accounting for 85% of all pupae sampled. Three habitats (all drums) accounted for 80% of all the pupae collected in the dry season. Predictors for pupal productivity in the wet season were habitat type, place (whether the habitat is located at the back or front of the house), habitat purpose (use of the water in the habitat), and source of water. Although the multivariate model for habitat type did not converge, habitat type and habitat size were the only significant predictors during the dry season. Drums, pots, and tires were sources of more than 85% of Ae. aegypti pupae, reinforcing the "key container concept." Targeting these three types of habitats makes epidemiological sense, especially during the dry season.
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Affiliation(s)
- Alawih S. Mwakutwaa
- Department of Environment and Health Sciences, Technical University of Mombasa, Mombasa, Kenya
| | - Harun N. Ngugi
- Department of Biological Sciences, Chuka University, Chuka, Kenya
| | - Bryson A. Ndenga
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Amy Krystosik
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA USA
| | - Moses Ngari
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Laila U. Abubakar
- Department of Pure and Applied Sciences, Technical University of Mombasa, Mombasa, Kenya
| | - Shadrack Yonge
- Department of Environment and Health Sciences, Technical University of Mombasa, Mombasa, Kenya
| | - Uriel Kitron
- Department of Environmental Sciences, Emory University, Atlanta, GA USA
| | - A. Desiree LaBeaud
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA USA
| | - Francis M. Mutuku
- Department of Environment and Health Sciences, Technical University of Mombasa, Mombasa, Kenya
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Entomo-Virological Aedes aegypti Surveillance Applied for Prediction of Dengue Transmission: A Spatio-Temporal Modeling Study. Pathogens 2022; 12:pathogens12010004. [PMID: 36678352 PMCID: PMC9861664 DOI: 10.3390/pathogens12010004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
Currently, DENV transmitted primarily by Aedes aegypti affects approximately one in three people annually. The spatio-temporal heterogeneity of vector infestation and the intensity of arbovirus transmission require surveillance capable of predicting an outbreak. In this work, we used data from 4 years of reported dengue cases and entomological indicators of adult Aedes collected from approximately 3500 traps installed in the city of Foz do Iguaçu, Brazil, to evaluate the spatial and temporal association between vector infestation and the occurrence of dengue cases. Entomological (TPI, ADI and MII) and entomo-virological (EVI) indexes were generated with the goal to provide local health managers with a transmission risk stratification that allows targeting areas for vector control activities. We observed a dynamic pattern in the evaluation; however, it was a low spatio-temporal correlation of Ae. aegypti and incidence of dengue. Independent temporal and spatial effects capture a significant portion of the signal given by human arbovirus cases. The entomo-virological index (EVI) significantly signaled risk in a few areas, whereas entomological indexes were not effective in providing dengue risk alert. Investigating the variation of biotic and abiotic factors between areas with and without correlation should provide more information about the local epidemiology of dengue.
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Mulderij-Jansen V, Pundir P, Grillet ME, Lakiang T, Gerstenbluth I, Duits A, Tami A, Bailey A. Effectiveness of Aedes-borne infectious disease control in Latin America and the Caribbean region: A scoping review. PLoS One 2022; 17:e0277038. [PMID: 36322603 PMCID: PMC9629598 DOI: 10.1371/journal.pone.0277038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 10/18/2022] [Indexed: 11/05/2022] Open
Abstract
Background Aedes aegypti and Aedes albopictus are primary vectors of emerging or re-emerging arboviruses that threaten public health worldwide. Many efforts have been made to develop interventions to control these Aedes species populations. Still, countries in the Latin America and the Caribbean (LAC) region struggle to create/design/develop sustainable and effective control strategies. This scoping review synthesises evidence concerning the effectiveness of Ae. aegypti and Ae. albopictus prevention and control interventions performed in LAC (2000–2021). The findings can be used to evaluate, compare and develop more effective control strategies. Methodology The review is based on the methodology by Joanna Briggs Institute for conducting a scoping review. The MEDLINE (via PubMed and Web of Science), Cochrane Library, Scopus, EMBASE and ScienceDirect databases were used to search for articles. Grey literature was searched from governmental and non-governmental organisation websites. Four reviewers independently screened all titles and abstracts and full-text of the articles using the Rayyan web application, based on pre-defined eligibility criteria. Results A total of 122 publications were included in the review. Most studies focused on dengue virus infection and data on Ae. aegypti. Entomological data were mainly used to determine the intervention’s effectiveness. An integrated control intervention was the most commonly employed strategy in both regions. Biological control measures, environmental management, and health education campaigns on community participation achieved more sustainable results than an intervention where only a chemical control measure was used. Challenges to implementing interventions were insufficient financial support, resources, workforce, intersectoral collaboration and legislation. Conclusions Based on the synthesised data, an integrated vector (Aedes) management focused on community participation seems to be the most effective approach to mitigate Aedes-borne infectious diseases. Maintaining the approach’s effect remains challenging as it requires multisectoral and multi-disciplinary team engagement and active community participation. Future research needs to address the barriers to program implementation and maintenance as data on this topic is lacking.
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Affiliation(s)
- Vaitiare Mulderij-Jansen
- Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Faculty of Geosciences, Department of Human Geography and Spatial Planning, International Development Studies, Utrecht University, Utrecht, Netherlands
- Department of Epidemiology, Curaçao Biomedical & Health Research Institute, Willemstad, Curaçao
- * E-mail:
| | - Prachi Pundir
- George Institute for Global Health, New Delhi, India
| | - Maria E. Grillet
- Facultad de Ciencias, Instituto de Zoología y Ecología Tropical, Universidad Central de Venezuela, Caracas, Venezuela
| | | | - Izzy Gerstenbluth
- Department of Epidemiology, Curaçao Biomedical & Health Research Institute, Willemstad, Curaçao
- Epidemiology and Research Unit, Ministry of Health Environment and Nature of Curaçao, Willemstad, Curaçao
| | - Ashley Duits
- Red Cross Blood Bank Foundation, Willemstad, Curaҫao
- Department of Immunology, Curaçao Biomedical & Health Research Institute, Willemstad, Curaçao
- Institute for Medical Education, University Medical Center Groningen, Groningen, The Netherlands
| | - Adriana Tami
- Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ajay Bailey
- Faculty of Geosciences, Department of Human Geography and Spatial Planning, International Development Studies, Utrecht University, Utrecht, Netherlands
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Leandro AS, de Castro WAC, Lopes RD, Delai RM, Villela DAM, de-Freitas RM. Citywide Integrated Aedes aegypti Mosquito Surveillance as Early Warning System for Arbovirus Transmission, Brazil. Emerg Infect Dis 2022; 28:701-706. [PMID: 35318912 PMCID: PMC8962889 DOI: 10.3201/eid2804.211547] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Infestation indices based on adult trapping predicted dengue outbreaks better than larval indices did. Arbovirus epidemiology lacks efficient and timely surveillance systems with accurate outbreak alert signals. We devised a citywide integrated surveillance system combining entomologic, epidemiologic, and entomo-virologic data gathered during 2017–2020 in Foz do Iguaçu, Brazil. We installed 3,476 adult mosquito traps across the city and inspected traps every 2 months. We compared 5 entomologic indices: traditional house and Breteau indices for larval surveys and trap positivity, adult density, and mosquitoes per inhabitant indices for adult trapping. We screened for dengue, Zika, and chikungunya viruses in live adult Aedes aegypti mosquitoes collected from traps. Indices based on adult mosquito sampling had higher outbreak predictive values than larval indices, and we were able to build choropleth maps of infestation levels <36 h after each round of trap inspection. Locating naturally infected vectors provides a timely support tool for local public health managers to prioritize areas for intervention response to prevent virus outbreaks.
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Review of the ecology and behaviour of Aedes aegypti and Aedes albopictus in Western Africa and implications for vector control. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2022; 2:100074. [PMID: 35726222 PMCID: PMC7612875 DOI: 10.1016/j.crpvbd.2021.100074] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Western Africa is vulnerable to arboviral disease transmission, having recently experienced major outbreaks of chikungunya, dengue, yellow fever and Zika. However, there have been relatively few studies on the natural history of the two major human arbovirus vectors in this region, Aedes aegypti and Ae. albopictus, potentially limiting the implementation of effective vector control. We systematically searched for and reviewed relevant studies on the behaviour and ecology of Ae. aegypti and Ae. albopictus in Western Africa, published over the last 40 years. We identified 73 relevant studies, over half of which were conducted in Nigeria, Senegal, or Côte d'Ivoire. Most studies investigated the ecology of Ae. aegypti and Ae. albopictus, exploring the impact of seasonality and land cover on mosquito populations and identifying aquatic habitats. This review highlights the adaptation of Ae. albopictus to urban environments and its invasive potential, and the year-round maintenance of Ae. aegypti populations in water storage containers. However, important gaps were identified in the literature on the behaviour of both species, particularly Ae. albopictus. In Western Africa, Ae. aegypti and Ae. albopictus appear to be mainly anthropophilic and to bite predominantly during the day, but further research is needed to confirm this to inform planning of effective vector control strategies. We discuss the public health implications of these findings and comment on the suitability of existing and novel options for control in Western Africa.
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Pinchoff J, Silva M, Spielman K, Hutchinson P. Use of effective lids reduces presence of mosquito larvae in household water storage containers in urban and peri-urban Zika risk areas of Guatemala, Honduras, and El Salvador. Parasit Vectors 2021; 14:167. [PMID: 33741050 PMCID: PMC7977570 DOI: 10.1186/s13071-021-04668-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 03/04/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In 2015, an outbreak of Zika virus spread across Latin America and the Caribbean (LAC). Public health programs promoted vector control behaviors, including covering water storage containers with lids. Such approaches disrupt Zika transmission by eliminating the habitats of the Aedes aegypti mosquito, which breeds in stagnant water. METHODS A quantitative household survey and observation checklist with trained enumerators were undertaken between August and October 2018 in selected urban/peri-urban USAID implementation communities in El Salvador, Guatemala, and Honduras. The survey included questions regarding knowledge, attitudes, and practices related to Zika virus. An accompanying checklist was implemented to observe water storage containers, including for short-term and long-term water use. The characteristics of these containers were tabulated, including the presence of a lid. The lids were examined for key features to determine their potential effectiveness to prevent mosquito breeding: fully covering and sealing the container, not having holes, and not having water on them (potentially creating a secondary breeding site). Multivariate logistic regression was used to estimate the effectiveness of lid types and characteristics on the presence of larvae. RESULTS Overall, in adjusted models, using an effective lid versus no lid was associated with a 94% decrease in odds of larval presence in long-term water storage containers (odds ratio = 0.06; 95% confidence interval [0.029, 0.152]); however, similar impacts were not observed for washbasins in the adjusted models. Models adjusted for household wealth, receiving a visit from a vector control technician, scrubbing the container in the last 7 days, and perception of more mosquitoes around. CONCLUSIONS Effective lids, if made available and coupled with complementary behavioral messaging, may reduce transmission of Zika and other Aedes mosquito-borne diseases in the LAC region.
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Dormont L, Mulatier M, Carrasco D, Cohuet A. Mosquito Attractants. J Chem Ecol 2021; 47:351-393. [PMID: 33725235 DOI: 10.1007/s10886-021-01261-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/18/2021] [Accepted: 03/02/2021] [Indexed: 01/01/2023]
Abstract
Vector control and personal protection against anthropophilic mosquitoes mainly rely on the use of insecticides and repellents. The search for mosquito-attractive semiochemicals has been the subject of intense studies for decades, and new compounds or odor blends are regularly proposed as lures for odor-baited traps. We present a comprehensive and up-to-date review of all the studies that have evaluated the attractiveness of volatiles to mosquitoes, including individual chemical compounds, synthetic blends of compounds, or natural host or plant odors. A total of 388 studies were analysed, and our survey highlights the existence of 105 attractants (77 volatile compounds, 17 organism odors, and 11 synthetic blends) that have been proved effective in attracting one or several mosquito species. The exhaustive list of these attractants is presented in various tables, while the most common mosquito attractants - for which effective attractiveness has been demonstrated in numerous studies - are discussed throughout the text. The increasing knowledge on compounds attractive to mosquitoes may now serve as the basis for complementary vector control strategies, such as those involving lure-and-kill traps, or the development of mass trapping. This review also points out the necessity of further improving the search for new volatile attractants, such as new compound blends in specific ratios, considering that mosquito attraction to odors may vary over the life of the mosquito or among species. Finally, the use of mosquito attractants will undoubtedly have an increasingly important role to play in future integrated vector management programs.
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Affiliation(s)
- Laurent Dormont
- CEFE, Univ Paul Valéry Montpellier 3, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, France.
| | - Margaux Mulatier
- Institut Pasteur de Guadeloupe, Laboratoire d'étude sur le contrôle des vecteurs (LeCOV), Lieu-Dit Morne Jolivièrex, 97139, Les Abymes, Guadeloupe, France
| | - David Carrasco
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
| | - Anna Cohuet
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
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Yee DA, Glasgow WC, Ezeakacha NF. Quantifying species traits related to oviposition behavior and offspring survival in two important disease vectors. PLoS One 2020; 15:e0239636. [PMID: 32976497 PMCID: PMC7518596 DOI: 10.1371/journal.pone.0239636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/10/2020] [Indexed: 11/19/2022] Open
Abstract
Animals with complex life cycles have traits related to oviposition and juvenile survival that can respond to environmental factors in similar or dissimilar ways. We examined the preference-performance hypothesis (PPH), which states that females lacking parental care select juvenile habitats that maximize fitness, for two ubiquitous mosquito species, Aedes albopictus and Culex quinquefasciatus. Specifically, we examined if environmental factors known to affect larval abundance patterns in the field played a role in the PPH for these species. We first identified important environmental factors from a field survey that predicted larvae across different spatial scales. We then performed two experiments, the first testing the independent responses of oviposition and larval survival to these environmental factors, followed by a combined experiment where initial oviposition decisions were allowed to affect larval life history measures. We used path analysis for this last experiment to determine important links among factors in explaining egg numbers, larval mass, development time, and survival. For separate trials, Aedes albopictus displayed congruence between oviposition and larval survival, however C. quinquefasciatus did not. For the combined experiment path analysis suggested neither species completely fit predictions of the PPH, with density dependent effects of initial egg number on juvenile performance in A. albopictus. For these species the consequences of female oviposition choices on larval performance do not appear to fit expectations of the PPH.
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Affiliation(s)
- Donald A. Yee
- School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, United States of America
- * E-mail:
| | - William C. Glasgow
- School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, United States of America
| | - Nnaemeka F. Ezeakacha
- School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, United States of America
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Parker AT, McGill K, Allan BF. Container Type Affects Mosquito (Diptera: Culicidae) Oviposition Choice. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1459-1467. [PMID: 32161973 DOI: 10.1093/jme/tjaa045] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Indexed: 06/10/2023]
Abstract
Larvae of container-breeding mosquitoes develop in a wide range of container habitats found in residential neighborhoods. Different mosquito species may exhibit preference for different container types and sizes. Due to phenological differences, species composition in container habitats may change over time. We first conducted weekly neighborhood container surveys to determine the types of container habitats found in residential neighborhoods, and to determine mosquito species composition over time within these habitats. We then conducted an oviposition choice field assay to determine whether female mosquitoes of different species preferentially oviposit in different container types commonly found in neighborhoods. Halfway through the experiment, the largest container was removed at half the sites to test the hypothesis that incomplete source reduction alters oviposition preference among the remaining containers. In the neighborhood surveys, large containers had the greatest mosquito densities and the highest species richness. Aedes albopictus (Skuse), the most commonly collected mosquito, was found in all container types. The oviposition experiment indicated that Culex spp. females preferentially oviposit in large containers. When the largest container was removed, the total number of egg rafts decreased. Aedes spp. females preferred to oviposit in large- and medium-sized containers, but the total number of eggs laid did not change when the large container was removed. These results confirm that understanding habitat preferences of container-breeding mosquitoes is important to control efforts targeting vector species and that incomplete removal of container habitats may have unpredictable consequences for the distribution of juveniles among remaining habitats.
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Affiliation(s)
- Allison T Parker
- Department of Biological Sciences, Northern Kentucky University, 254 Science Center, 1 Nunn Dr., Highland Heights, KY
| | - Kelsey McGill
- School of Integrative Biology, University of Illinois Urbana-Champaign, Urbana, IL
| | - Brian F Allan
- School of Integrative Biology, University of Illinois Urbana-Champaign, Urbana, IL
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL
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Forsyth JE, Mutuku FM, Kibe L, Mwashee L, Bongo J, Egemba C, Ardoin NM, LaBeaud AD. Source reduction with a purpose: Mosquito ecology and community perspectives offer insights for improving household mosquito management in coastal Kenya. PLoS Negl Trop Dis 2020; 14:e0008239. [PMID: 32392226 PMCID: PMC7241847 DOI: 10.1371/journal.pntd.0008239] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 05/21/2020] [Accepted: 03/20/2020] [Indexed: 01/17/2023] Open
Abstract
Understanding mosquito breeding behavior as well as human perspectives and practices are crucial for designing interventions to control Aedes aegypti mosquito-borne diseases as these mosquitoes primarily breed in water-holding containers around people's homes. The objectives of this study were to identify productive mosquito breeding habitats in coastal Kenya and to understand household mosquito management behaviors and their behavioral determinants. The field team conducted entomological surveys in 444 households and semi-structured interviews with 35 female caregivers and 37 children in Kwale County, coastal Kenya, between May and December 2016. All potential mosquito habitats with or without water were located, abundances of mosquito immatures measured and their characteristics recorded. Interviews explored household mosquito management behaviors and their behavioral determinants. 2,452 container mosquito habitats were counted containing 1,077 larvae and 390 pupae, predominantly Aedes species. More than one-third of the positive containers were found outside houses in 1 of the 10 villages. Containers holding water with no intended purpose contained 55.2% of all immature mosquitoes. Containers filled with rainwater held 95.8% of all immature mosquitoes. Interviews indicated that households prioritize sleeping under bednets as a primary protection against mosquito-borne disease because of concern about night-time biting, malaria-transmitting Anopheles mosquitoes. Respondents had limited knowledge about the mosquito life cycle, especially with respect to day-time biting, container-breeding Aedes mosquitoes. Therefore, respondents did not prioritize source reduction. Most mosquitoes breed in containers that have no direct or immediate purpose ("no-purpose containers"). These containers may be left unattended for several days allowing rainwater to collect, and creating ideal conditions for mosquito breeding. An intervention that requires little effort and targets only the most productive containers could effectively reduce mosquito indices and, relatedly, mosquito-borne disease risk.
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Affiliation(s)
- Jenna E. Forsyth
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, California, United States of America
- * E-mail:
| | - Francis M. Mutuku
- Technical University of Mombasa, Mombasa, Kenya
- Vector-Borne Disease Unit, Msambweni County Referral Hospital, Msambweni, Kenya
| | - Lydiah Kibe
- Centre for Geographic Medicine Research Coast, Kenya Medical Research Institute, Kilifi, Kenya
| | - Luti Mwashee
- Technical University of Mombasa, Mombasa, Kenya
- Vector-Borne Disease Unit, Msambweni County Referral Hospital, Msambweni, Kenya
| | - Joyce Bongo
- Vector-Borne Disease Unit, Msambweni County Referral Hospital, Msambweni, Kenya
| | - Chika Egemba
- Stanford University School of Medicine, Stanford, California, United States of America
| | - Nicole M. Ardoin
- Emmett Interdisciplinary Program in Environment and Resources, Graduate School of Education, and Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - A. Desiree LaBeaud
- Stanford University School of Medicine, Stanford, California, United States of America
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Medone P, Hernï Ndez-Suï Rez CM. 'Swimming mosquitoes': a key stepping stone to prevent Dengue, Zika and Chikungunya: an educative experience in Colima, Mexico. HEALTH EDUCATION RESEARCH 2019; 34:389-399. [PMID: 31329869 DOI: 10.1093/her/cyz012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 04/16/2019] [Indexed: 06/10/2023]
Abstract
Dengue, Zika and Chikungunya arboviruses (DZC), mainly transmitted by mosquito Aedes aegypti, are global health public issues affecting 390 million people each year. In most endemic countries, vector control strategies have been focused on reducing breeding sites and adult mosquito populations. Most health communication strategies have pointed out adult mosquito as the main responsible of the transmission, persuading people to eliminate domestic containers. However, it is not clear how should people understand the relationship between adult mosquitoes and water domestic containers. So, the main goal of the present study was to assess the people understanding of this relationship. Results showed that most people associate adult mosquitoes with DZC, but only few could associate swimming larvae with mosquitoes. The unawareness of larva presence leads to an underestimation of risk perception about DZC transmission. In this context, we consider that educative interventions for health promotion, based on meaningful knowledge and social representations arise as long-term strategies to control transmission of vector-borne diseases. Here, we propose innovative health strategies focused on increase the risk perception about swimming larvae, considering social representations, which may be a key stepping stone to increase people adherence to massive campaigns and reducing DZC burden.
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Affiliation(s)
- Paula Medone
- Secretar�a de Educaci�n, Direcci�n de Desarrollo de la Gesti�n y la Calidad Educativa, Av. Gonzalo de Sandoval 760, Las V�boras, Colima, M�xico
| | - Carlos M Hernï Ndez-Suï Rez
- Facultad de Ciencias, Universidad de Colima, Bernal D�az del Castillo No. 340, Col. Villas San Sebasti�n, CP Colima, M�xico
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13
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Parker AT, Gardner AM, Perez M, Allan BF, Muturi EJ. Container Size Alters the Outcome of Interspecific Competition Between Aedes aegypti (Diptera: Culicidae) and Aedes albopictus. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:708-715. [PMID: 30566608 DOI: 10.1093/jme/tjy215] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Indexed: 06/09/2023]
Abstract
Aedes aegypti L. and Aedes albopictus Skuse co-occur in a variety of water-filled containers where they compete for resources. Larvae of Ae. albopictus Skuse often outcompete those of Ae. aegypti L., but variation in biotic and abiotic parameters can modify the outcome of this interspecific competition. We tested whether container size can alter the magnitude and direction of intra- and interspecific competition by rearing three Ae. aegypti and Ae. albopictus larval combinations (100:0, 50:50 and 0:100) in three container sizes (small, medium, and large). For both mosquito species, individuals raised in small- and medium-sized containers had shorter development time to adulthood, higher survival to adulthood, and larger adult body size compared to individuals from large containers. For Ae. aegypti but not Ae. albopictus, survival to adulthood was significantly influenced by a two-way interaction between container size and larval competition. The negative effect of interspecific competition was stronger in the small and medium containers and the negative effect of intraspecific competition was stronger in large containers. Our results show that container size can affect the outcome of intra- and interspecific competition between Ae. aegypti and Ae. albopictus and may help account for the observed patterns of both competitive exclusion and coexistence documented in the field for these two medically important mosquito species.
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Affiliation(s)
- Allison T Parker
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL
| | | | - Manuel Perez
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL
| | - Brian F Allan
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL
| | - Ephantus J Muturi
- Crop Bioprotection Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Peoria, IL
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14
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Shragai T, Harrington LC. Aedes albopictus (Diptera: Culicidae) on an Invasive Edge: Abundance, Spatial Distribution, and Habitat Usage of Larvae and Pupae Across Urban and Socioeconomic Environmental Gradients. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:472-482. [PMID: 30566612 DOI: 10.1093/jme/tjy209] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Indexed: 06/09/2023]
Abstract
The Asian tiger mosquito [Aedes albopictus (Skuse)] is an invasive species of public health importance that is currently expanding its range in the Northeast United States. Effective Ae. albopictus control depends on a thorough understanding of factors influencing their abundance, spatial distribution, and habitat preference. We conducted a series of container surveys for Ae. albopictus larvae/pupae over 2 yr across nine sites in neighborhoods along its invasive range in southern New York. Selected sites represented a gradient of percent impervious surface and median household income. Two hypotheses were tested: 1) Ae. albopictus larval/pupal abundance increases and spatial distribution becomes less clustered as site-level median income decreases and percent impervious surface increases because of increased larval habitat quality and availability; and 2) container-level characteristics are predictive of Ae. albopictus larval/pupal infestation across a range of sites. In 2016, neither median household income nor impervious surface predicted Ae. albopictus abundance. In 2017, sites with greater impervious surface were more heavily infested by some measures. In both years, Ae. albopictus larval/pupal spatial distribution as measured by K-function was more clustered in with greater median household income. Most container characteristics were either not predictive of Ae. albopictus or varied between years. Based on the variability of predictive container characteristics, we conclude that identification of key containers is not useful in this region. However, Ae. albopictus can be nonhomogenously distributed or abundant based on income level and impervious surface. Improved control of immatures should consider these regional predictors of Ae. albopictus populations.
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Affiliation(s)
- Talya Shragai
- Department of Entomology, Cornell University, Ithaca, NY
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15
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Bibbs CS, Crosier JE, D'Amato JM, Gibson-Corrado J, Xue RD. Bromeliad targeted foliar treatments with Aqualuer ® 20-20 for hot spot mitigation using three hand sprayers against Aedes albopictus (Diptera: Culicidae). JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2018; 43:215-219. [PMID: 30408298 DOI: 10.1111/jvec.12305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/25/2018] [Indexed: 06/08/2023]
Abstract
Bromeliads serve as a key environmental resource for Aedes albopictus (Skuse) in some peridomestic landscapes and are not addressed through conventional source reduction. As an alternative, three handheld sprayers were evaluated in point-source applications of permethrin to bromeliads in Saint Augustine, FL. Each machine was screened for its utility in point-source harborage treatments, while we simultaneously evaluated bromeliad-focused treatments for reducing Ae. albopictus egg abundance in bromeliad plants. Semi-field tests against caged Ae. albopictus produced 100% mortality at 24 h with each sprayer. Three field sites were assigned to each machine and a control, and bromeliad residual applications of Aqualuer 20-20® were assessed through egg surveillance using ovitraps both within and beyond 30 m of the treated bromeliad harborage. The treatment decreased Ae. albopictus egg abundance across the field sites for three weeks post-treatment with no significant differences among the equipment. Functional differences among machines, such as automated pressure control or leak guards on the nozzle, depend on the accessories that offer the greatest logistical benefit to the user. The field results suggest bromeliads are a viable target for harborage treatments. Selective treatments to bromeliads could offer a possible solution to containers that homeowners refuse to eliminate.
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Affiliation(s)
- Christopher S Bibbs
- Anastasia Mosquito Control District of St. Johns County, 120 EOC Drive, St. Augustine, FL 32092, U.S.A
| | - Jesse E Crosier
- Anastasia Mosquito Control District of St. Johns County, 120 EOC Drive, St. Augustine, FL 32092, U.S.A
- St. Johns County Department of Health, 200 San Sebastian View, St. Augustine, FL 32084, U.S.A
| | - Joseph M D'Amato
- Anastasia Mosquito Control District of St. Johns County, 120 EOC Drive, St. Augustine, FL 32092, U.S.A
| | - Jennifer Gibson-Corrado
- Anastasia Mosquito Control District of St. Johns County, 120 EOC Drive, St. Augustine, FL 32092, U.S.A
- St. Johns County Department of Health, 200 San Sebastian View, St. Augustine, FL 32084, U.S.A
| | - Rui-De Xue
- Anastasia Mosquito Control District of St. Johns County, 120 EOC Drive, St. Augustine, FL 32092, U.S.A
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16
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Degroote S, Zinszer K, Ridde V. Interventions for vector-borne diseases focused on housing and hygiene in urban areas: a scoping review. Infect Dis Poverty 2018; 7:96. [PMID: 30173670 PMCID: PMC6120073 DOI: 10.1186/s40249-018-0477-5] [Citation(s) in RCA: 18] [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: 02/13/2018] [Accepted: 08/06/2018] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Over half the world's human populations are currently at risk from vector-borne diseases (VBDs), and the heaviest burden is borne by the world's poorest people, communities, and countries. The aim of this study was to conduct a review on VBD interventions relevant to housing and hygiene (including sanitation and waste management) in urban areas. MAIN BODY We conducted a scoping review, which involved systematically searching peer-reviewed and grey literature published between 2000 and 2016 using five scientific databases and one database for grey literature. Different data extraction tools were used for data coding and extraction. We assessed the quality of each study using the Mixed Methods Appraisal Tool and extracted descriptive characteristics and data about implementation process and transferability from all studies using the Template for Intervention Description and Replication and ASTAIRE (a tool for analyzing the transferability of health promotion interventions) tools. We reviewed 44 studies. Overall, the studies were judged to be of high risk for bias. Our results suggest multifaceted interventions, particularly community-based interventions, have the potential to achieve wider and more sustained effects than do standard vertical single-component programs. The evaluations of multifaceted interventions tend to include integrated evaluations, using not only entomological indicators but also acceptability and sustainability indicators. CONCLUSIONS This review highlighted the important need for higher quality research in VBDs and improved and standardized reporting of interventions. Significant research gaps were found regarding qualitative research and implementation research, and results highlighted the need for more interventions focus on sanitation and hygiene practices.
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Affiliation(s)
- Stéphanie Degroote
- University of Montreal Public Health Research Institute, Montreal, Canada.
| | - Kate Zinszer
- University of Montreal Public Health Research Institute, Montreal, Canada
| | - Valéry Ridde
- University of Montreal Public Health Research Institute, Montreal, Canada
- French Institute For Research on sustainable Development (IRD), IRD Paris Descartes University (CEPED), Paris Sorbonne Cities University, Erl Inserm Sagesud, Paris, France
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17
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Bibbs CS, Hahn DA, Kaufman PE, Xue RD. Sublethal effects of a vapour-active pyrethroid, transfluthrin, on Aedes aegypti and Ae. albopictus (Diptera: Culicidae) fecundity and oviposition behaviour. Parasit Vectors 2018; 11:486. [PMID: 30157907 PMCID: PMC6114540 DOI: 10.1186/s13071-018-3065-4] [Citation(s) in RCA: 18] [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: 05/30/2018] [Accepted: 08/17/2018] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND It is assumed that mosquitoes surviving exposure to spatial repellents when attempting to bite a host will not have significant adverse impacts on their downstream biology. Therefore, a critical knowledge gap is understanding the extent to which sublethal exposure to volatile pyrethroids may damage the performance of mosquitoes that survive exposure to vapour-active pyrethroids. To address this, laboratory-reared Aedes aegypti (L.) and Ae. albopictus (Skuse) were exposed to one of three sublethal concentrations of transfluthrin before being offered a blood-meal, after which their survival, fecundity, fertility, and egg-laying behaviour was assessed. RESULTS Both species expressed reduced skip-oviposition behaviour at all exposures. Both species also suffered a major reduction in viable eggs (50-75% reduction in viable eggs laid). A phenotype where eggs collapsed after laying was observed in Ae. aegypti, and this response increased with exposure concentrations. Dissected females of both species retained 50% or fewer of their eggs, with Ae. albopictus retaining a significant proportion of melanised oocytes following the highest exposure. CONCLUSIONS Our findings suggest that volatile pyrethroids can reduce skip-oviposition, which may improve source reduction outcomes during integrated management. The additional fecundity reduction caused by sublethal exposures to volatile pyrethroids improves our confidence in recommending them for urban vector management. Furthermore, we suggest that volatile pyrethroids should be adapted into delivery methods compatible with mosquito abatement programs.
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Affiliation(s)
- Christopher S. Bibbs
- Entomology and Nematology Department, University of Florida, 1881 Natural Area Drive, Gainesville, FL 32611 USA
- Anastasia Mosquito Control District of St. Johns County, 120 EOC Drive, St. Augustine, FL 32092 USA
| | - Daniel A. Hahn
- Entomology and Nematology Department, University of Florida, 1881 Natural Area Drive, Gainesville, FL 32611 USA
| | - Phillip E. Kaufman
- Entomology and Nematology Department, University of Florida, 1881 Natural Area Drive, Gainesville, FL 32611 USA
| | - Rui-de Xue
- Anastasia Mosquito Control District of St. Johns County, 120 EOC Drive, St. Augustine, FL 32092 USA
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18
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Darriet F. Synergistic Effect of Fertilizer and Plant Material Combinations on the Development of Aedes aegypti (Diptera: Culicidae) and Anopheles gambiae (Diptera: Culicidae) Mosquitoes. JOURNAL OF MEDICAL ENTOMOLOGY 2018; 55:496-500. [PMID: 29309617 DOI: 10.1093/jme/tjx231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Indexed: 06/07/2023]
Abstract
Chemical fertilizers are used everywhere, which often pollute the breeding sites of mosquitoes. In this laboratory study, the consequences on Aedes aegypti (L.) (Diptera: Culicidae) and Anopheles gambiae (Giles) (Diptera: Culicidae) of water-containing plant matter (PM) alone, or in association with an NPK type of fertilizer (PM+NPK), were evaluated. To obtain a 20% imaginal emergence of An. gambiae (IEt20), the bioassays carried out with PM have evidenced that its larvae need four times as much food as for Ae. aegypti larvae. The PM+NPK combinations significantly improve the survival rates of both mosquitoes multiplying the percentages of imaginal emergence by 1.7-3 (synergistic effect). The log-probit analysis of the adult emergence also reveals that the environments containing fertilizers accelerates by two to four times the development of the mosquito larvae.
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Affiliation(s)
- Frédéric Darriet
- Institut de Recherche pour le Développement (IRD), UMR MIVEGEC Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, France
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19
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Farnesi LC, Barbosa CS, Araripe LO, Bruno RV. The influence of a light and dark cycle on the egg laying activity of Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae). Mem Inst Oswaldo Cruz 2018; 113:e170362. [PMID: 29412343 PMCID: PMC5851057 DOI: 10.1590/0074-02760170362] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 12/27/2017] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND The epidemiological importance of the mosquito Aedes aegypti as a vector of multiple human pathogens has generated a growing number of studies on the physiology and behaviour of its blood-feeding females. The activity of oviposition is one of the critical elements contributing to the expansion of Ae. aegypti's populations. Although there is a vast literature about oviposition behaviour, significant specific knowledge about egg viability and female fertility under light and dark conditions is still lacking. OBJECTIVES We studied, in controlled laboratory conditions, the effect that light and dark cycles have on the efficiency of oviposition by Ae. aegypti females. METHODS Physiological assays were performed using synchronised eggs obtained from forced egg laying. The number and viability of eggs was analysed under three different light/dark regimes: LD12:12 (12 h of light and 12 h of dark), DD (constant darkness) and LL (constant light). FINDINGS AND CONCLUSIONS Our results show that females prefer to lay their eggs in dark conditions, but maximising the number and viability of eggs requires the occurrence of a light/dark cycle. Ongoing research on this theme has the potential of contributing to the proposition of new strategies for control based on the failure of egg laying and hatching.
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Affiliation(s)
- Luana Cristina Farnesi
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia Molecular de Insetos, Rio de Janeiro, RJ, Brasil
| | - Christine Silveira Barbosa
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia Molecular de Insetos, Rio de Janeiro, RJ, Brasil
| | - Luciana Ordunha Araripe
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia Molecular de Insetos, Rio de Janeiro, RJ, Brasil
| | - Rafaela Vieira Bruno
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia Molecular de Insetos, Rio de Janeiro, RJ, Brasil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brasil
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20
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Lamichhane RS, Neville PJ, Oosthuizen J, Clark K, Mainali S, Fatouros M, Beatty S. The Highs and Lows of Making a Bucket List-Quantifying Potential Mosquito Breeding Habitats in Metropolitan Backyards. Front Public Health 2017; 5:292. [PMID: 29164098 PMCID: PMC5681743 DOI: 10.3389/fpubh.2017.00292] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 10/20/2017] [Indexed: 11/27/2022] Open
Abstract
While the development of land for residential housing along the Swan and Canning Rivers in Perth, WA, Australia has reduced natural mosquito breeding sites, the role of backyard container breeding remains a relatively unknown factor. Local Governments responsible for these areas focus management and control efforts on low lying, tidally driven mosquito habitats to control Aedes vigilax (Skuse) and Aedes camptorhynchus (Thomson) mosquitoes in an effort to reduce both the nuisance and disease risk to residents. In spite of their efforts, Local Governments continue to receive complaints regarding mosquito nuisance, even when environmental conditions do not favor hatching and development of the two species in the Swan River tidal flats. In this study, 150 backyard inspections were conducted in the residential suburb of Bassendean, Perth, WA, Australia, situated in close proximity to the Swan River tidal plain. The occurrence and species composition of the mosquito fauna found in residential backyards was documented. Of the backyards inspected, 94% were found to possess containers capable of breeding mosquitoes, although only 3% contained mosquito larvae. Nine species of mosquito were collected from containers ranging in capacity from 0.05 to 50 L across the study area. Additionally, encephalitis virus surveillance trapping was conducted within residential properties and compared to the tidally driven natural habitat at Ashfield Flats and a tidally influenced brackish creekline at Bindaring Park. The species composition of the fauna at the three habitat types differed significantly, with Aedes notoscriptus (Skuse) dominating residential lots and A. vigilax more prevalent at the saltmarsh site. Bindaring Park had an adult composition at the mid-point of these two habitats, reflecting its proximity to both the Swan River and residential lots.
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Affiliation(s)
- Ram Sharan Lamichhane
- School of Medical & Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | - Peter J Neville
- School of Medical & Health Sciences, Edith Cowan University, Joondalup, WA, Australia.,Medical Entomology, Environmental Health Directorate, Public Health Division, Department of Health, Perth, WA, Australia
| | - Jacques Oosthuizen
- School of Medical & Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | - Kim Clark
- School of Medical & Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | - Samir Mainali
- School of Medical & Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | - Maria Fatouros
- Environmental Health Officer, Town of Bassendean, Perth, WA, Australia
| | - Shelley Beatty
- School of Medical & Health Sciences, Edith Cowan University, Joondalup, WA, Australia
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21
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Allgood DW, Yee DA. Oviposition preference and offspring performance in container breeding mosquitoes: evaluating the effects of organic compounds and laboratory colonisation. ECOLOGICAL ENTOMOLOGY 2017; 42:506-516. [PMID: 28989226 PMCID: PMC5625354 DOI: 10.1111/een.12412] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The preference-performance hypothesis predicts that organisms lacking parental care should oviposit in habitats that optimize offspring performance. We investigated preference-performance relationships for the Asian tiger mosquito (Aedes albopictus Skuse) and the southern house mosquito (Culex quinquefasciatus Say) (Diptera:Culicidae), two medically important container-breeding species, in response to an organic chemical blend mimicking decaying plant matter. Additionally, we evaluated the effects of long-term laboratory colonization of Cx. quinquefasciatus by using wild and laboratory strains.Oviposition bioassays were conducted by releasing gravid mosquitoes into field enclosures with automobile tires containing low and high concentrations of the chemical blend, and water controls. The offspring were then reared in water collected from the tires in which they were deposited.Aedes albopictus and wild Cx. quinquefasciatus laid more eggs in the chemical blend than water controls but did not differentiate between the low and high concentrations. Conversely, laboratory Cx. quinquefasciatus only preferred the high concentration to the low concentration. No statistical associations between oviposition preference and larval survival were found, as the chemical blend did not affect survivorship of either species.The oviposition preference for the chemical blend over water controls suggests that both species oviposit in the best available resource environment, but further studies are needed before conclusions regarding preference-performance relationships can be drawn.We found that long-term laboratory colonization affects oviposition behavior in Cx. quinquefasciatus, suggesting that behavioral studies on laboratory strains are not always applicable to wild populations.
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Affiliation(s)
- David W Allgood
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Donald A Yee
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, Mississippi, USA
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Nagpal BN, Gupta SK, Shamim A, Vikram K, Srivastava A, Tuli NR, Saxena R, Singh H, Singh VP, Bhagat VN, Yadav NK, Valecha N. Control of Aedes aegypti Breeding: A Novel Intervention for Prevention and Control of Dengue in an Endemic Zone of Delhi, India. PLoS One 2016; 11:e0166768. [PMID: 27918577 PMCID: PMC5137876 DOI: 10.1371/journal.pone.0166768] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 11/03/2016] [Indexed: 12/03/2022] Open
Abstract
Background and objective The study is based on hypothesis that whether continuous entomological surveillance of Ae. aegypti and simultaneous appropriate interventions in key containers during non-transmission (December–May) months would have any impact on breeding of Aedes and dengue cases during the following transmission months (June–November). The impact of the surveillance and intervention measures undertaken during non-transmission months were assessed by entomological indicators namely container index (CI), house index (HI), pupal index (PI) and breteau index (BI). Methods A total of 28 localities of West Zone of Delhi with persistent dengue endemicity were selected for the study. Out of these localities, 20 were included in study group while other 8 localities were in control group. IEC and various Aedes breeding control activities were carried out in study group in both non-transmission and transmission season whereas control group did not have any such interventions during non-transmission months as per guidelines of MCD. These activities were undertaken by a team of investigators from NIMR and SDMC, Delhi. In control group, investigators from NIMR carried out surveillance activity to monitor the breeding of Aedes mosquito in localities. Results Comparison of baseline data revealed that all indices in control and study group of localities were comparable and statistically non-significant (p>0.05). In both study and control groups, indices were calculated after pooling data on seasonal basis, i.e., transmission and non-transmission months for both years. The test of significance conducted on all the four indices, i.e., HI, PI, CI, and BI, revealed a significant difference (p<0.05) between the study group and control group during transmission and non-transmission months except in HI. Due to consistent intervention measures undertaken in non-transmission months in study group, reduction in CI, HI, BI and PI was observed 63%, 62%, 64% and 99% respectively during transmission months as compared to control group where increase of 59%, 102%, 73% and 71% respectively. As a result of reduction in larval indices, no dengue case (except one NS1) was observed in study group, whereas 38 dengue cases were observed in control group. Conclusion Through this pilot study, it is concluded that proper intervention in non-transmission season reduces vector density and subsequently dengue cases in transmission season.
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Affiliation(s)
- B. N. Nagpal
- National Institute of Malaria Research (NIMR), New Delhi, India
- * E-mail:
| | | | - Arshad Shamim
- National Institute of Malaria Research (NIMR), New Delhi, India
| | - Kumar Vikram
- National Institute of Malaria Research (NIMR), New Delhi, India
| | | | - N. R. Tuli
- Municipal Corporation of Delhi (MCD), Delhi, India
| | - Rekha Saxena
- National Institute of Malaria Research (NIMR), New Delhi, India
| | - Himmat Singh
- National Institute of Malaria Research (NIMR), New Delhi, India
| | - V. P. Singh
- Department of Health Research (DHR), Ministry of Health & Family Welfare, Delhi, India
| | - V. N. Bhagat
- Municipal Corporation of Delhi (MCD), Delhi, India
| | - N. K. Yadav
- Municipal Corporation of Delhi (MCD), Delhi, India
| | - Neena Valecha
- National Institute of Malaria Research (NIMR), New Delhi, India
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Garcia GDA, dos Santos LMB, Villela DAM, Maciel-de-Freitas R. Using Wolbachia Releases to Estimate Aedes aegypti (Diptera: Culicidae) Population Size and Survival. PLoS One 2016; 11:e0160196. [PMID: 27479050 PMCID: PMC4968812 DOI: 10.1371/journal.pone.0160196] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/15/2016] [Indexed: 11/20/2022] Open
Abstract
Mosquitoes carrying the endosymbiont bacterium Wolbachia have been deployed in field trials as a biological control intervention due to Wolbachia effects on reducing transmission of arboviruses. We performed mark, release and recapture (MRR) experiments using Wolbachia as an internal marker with daily collections with BG-Traps during the first two weeks of releases in Rio de Janeiro, Brazil. The MRR design allowed us to investigate two critical parameters that determine whether Wolbachia would successful invade a field population: the probability of daily survival (PDS) of Wolbachia-infected Aedes aegypti females, and the wild population density during releases. Released females had a PDS of 0.82 and 0.89 in the first and second weeks, respectively, immediately after releases, which is well within the range of previous estimates of survivorship of wild mosquitoes in Rio de Janeiro. Abundance estimation of wild population varied up to 10-fold higher depending on the estimation method used (634–3565 females on the average-difference model to 6365–16188 females according to Lincoln-Petersen). Wolbachia-released mosquitoes were lower than the density estimation of their wild counterparts, irrespectively of the model used. Individually screening mosquitoes for the presence of Wolbachia reduced uncertainty on abundance estimations due to fluctuation in capturing per week. A successful invasion into local population requires Ae. aegypti fitness is unaffected by Wolbachia presence, but also reliable estimates on the population size of wild mosquitoes.
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Affiliation(s)
- Gabriela de Azambuja Garcia
- Laboratório de Transmissão de Hematozoários, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, Brazil
| | - Lilha Maria Barbosa dos Santos
- Laboratório de Transmissão de Hematozoários, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, Brazil
| | | | - Rafael Maciel-de-Freitas
- Laboratório de Transmissão de Hematozoários, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, Brazil
- * E-mail:
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Darriet F. An anti-mosquito mixture for domestic use, combining a fertiliser and a chemical or biological larvicide. PEST MANAGEMENT SCIENCE 2016; 72:1340-1345. [PMID: 26414239 DOI: 10.1002/ps.4157] [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] [Received: 04/24/2015] [Revised: 09/14/2015] [Accepted: 09/22/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND Plant saucers are an important larval habitat for Aedes aegypti and Ae. albopictus in peridomestic situations. Because NPK fertilisers in plant containers tend to enhance the oviposition of these species, we investigated the effects of Bacillus thuringiensis var. israelensis, spinosad, pyriproxyfen and diflubenzuron larvicides in combination with fertiliser on the adult emergence and fecundity of the mosquitoes coming from plant saucers in controlled greenhouse experiments. NPK + larvicide (NPK-LAV) treatments were tested on Ae. aegypti. Each treatment was compared with water and with fertiliser alone on a total of five houseplants and their saucers. The fertilising treatment was renewed every 30-45 days. RESULTS With less than 5% imaginal emergence, the NPK + spinosad 0.5% treatment remained effective for 30 days. Both NPK + pyriproxyfen 0.1% and NPK + diflubenzuron 0.25% were effective for 45 days. The average number of eggs laid in the three treatments was similar to the NPK treatment, indicating that spinosad, pyriproxyfen and diflubenzuron did not alter the attraction effect of the fertiliser on egg laying. NPK + pyriproxyfen and NPK + diflubenzuron also had ovicidal activity and an important impact on the fecundity of the Ae. aegypti female imagos and the fertility of their eggs. CONCLUSION The addition of NPK fertiliser to insecticides can increase larval control of Aedes mosquitoes. This innovative measure for personal protection, which is harmless for both humans and animals, would be an additional support for the community-based actions led by the institutional services for vector control. © 2015 Society of Chemical Industry.
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Affiliation(s)
- Frédéric Darriet
- Institut de Recherche pour le Développement (IRD), UMR MIVEGEC (UM1-UM2-CNRS 5290-IRD 224), Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Montpellier, France
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Unlu I, Klingler K, Indelicato N, Faraji A, Strickman D. Suppression of Aedes albopictus, the Asian tiger mosquito, using a 'hot spot' approach. PEST MANAGEMENT SCIENCE 2016; 72:1427-1432. [PMID: 26482455 DOI: 10.1002/ps.4174] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/21/2015] [Accepted: 10/15/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND Recent changes in climate and human behavior have led to dramatic increases in the abundance and geographic expansion of invasive mosquito vectors such as Aedes albopictus. Although source reduction has been shown to be effective in reducing mosquito populations, thousands of backyards need to be inspected during door-to-door campaigns, which is labor intensive and expensive. We identified 'hot spots' as high (five or more female or male Ae. albopictus) adult mosquito populations at very focal locations. We tested whether hot spot source reduction efforts were effective in reducing mosquito populations in the early summer season (June to July). RESULTS Analysis of historical data from the study sites indicated the proportion of hot spots in the control site relative to the intervention site was much greater in 2011, when hot spot treatments were applied to the intervention site, than in 2012, 2013 and 2014 combined, when no sites were treated [OR (95% CI) = 3.9 (1.8, 8.5), Z = 3.39, P < 0.001). CONCLUSION Hot spot treatments can be incorporated into existing integrated mosquito management programs to increase effectiveness while reducing the time, cost and effort spent on methods such as door-to-door source reduction. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
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Affiliation(s)
- Isik Unlu
- Center for Vector Biology, Rutgers University, New Brunswick, NJ, USA
- Mercer County Mosquito Control, West Trenton, NJ, USA
| | - Kim Klingler
- Mercer County Mosquito Control, West Trenton, NJ, USA
| | | | - Ary Faraji
- Center for Vector Biology, Rutgers University, New Brunswick, NJ, USA
- Salt Lake City Mosquito Abatement District, Salt Lake City, UT, USA
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Harburguer L, Licastro S, Masuh H, Zerba E. Biological and Chemical Characterization of a New Larvicide Ovitrap Made of Plastic With Pyriproxyfen Incorporated for Aedes aegypti (Diptera: Culicidae) Control. JOURNAL OF MEDICAL ENTOMOLOGY 2016; 53:647-652. [PMID: 27052297 DOI: 10.1093/jme/tjw022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/20/2016] [Indexed: 06/05/2023]
Abstract
Aedes aegypti (L.) is a species of international concern because of its ability to transmit serious human arboviral diseases including yellow fever, dengue, and chikungunya, which have spread to all continents. Ovitraps are containers constructed to imitate Aedes' natural breeding sites and have been used for many decades as a sensitive and inexpensive surveillance tool for detecting the presence of container-inhabiting mosquitoes. In addition to their value for vector surveillance, various ovitrap devices have been evaluated as tools for suppressing Ae. aegypti populations. In this study, we performed a biological and chemical characterization of a new ovitrap prototype manufactured by injection molding of low-density polyethylene (LDPE) with the larvicide pyriproxyfen. Our research shows that pyriproxyfen was immediately released from the LDPE into the water of the ovitrap and led to an emergence inhibition of 100% for over 30 weeks. In addition, ovitraps continued to show a high larvicidal activity after over 20 washes. Pyriproxyfen was detectable in the water after 20 s and reached a peak after 24 h. Our results show that this ovitrap can be an effective, inexpensive, and low-maintenance tool for Ae. aegypti surveillance and control.
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Affiliation(s)
- Laura Harburguer
- Centro de Investigaciones de Plagas e Insecticidas (CIPEIN-UNIDEF/CITEDEF/CONICET), J.B. de LaSalle 4397, Villa Martelli (1603), Buenos Aires, Argentina (; ; ; ),
| | - Susana Licastro
- Centro de Investigaciones de Plagas e Insecticidas (CIPEIN-UNIDEF/CITEDEF/CONICET), J.B. de LaSalle 4397, Villa Martelli (1603), Buenos Aires, Argentina (; ; ; )
| | - Héctor Masuh
- Centro de Investigaciones de Plagas e Insecticidas (CIPEIN-UNIDEF/CITEDEF/CONICET), J.B. de LaSalle 4397, Villa Martelli (1603), Buenos Aires, Argentina (; ; ; ),
- Instituto de Investigaciones e Ingeniería Ambiental (3IA), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Eduardo Zerba
- Centro de Investigaciones de Plagas e Insecticidas (CIPEIN-UNIDEF/CITEDEF/CONICET), J.B. de LaSalle 4397, Villa Martelli (1603), Buenos Aires, Argentina (; ; ; )
- Instituto de Investigaciones e Ingeniería Ambiental (3IA), Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
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Baldacchino F, Caputo B, Chandre F, Drago A, della Torre A, Montarsi F, Rizzoli A. Control methods against invasive Aedes mosquitoes in Europe: a review. PEST MANAGEMENT SCIENCE 2015; 71:1471-85. [PMID: 26037532 DOI: 10.1002/ps.4044] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 04/19/2015] [Accepted: 05/15/2015] [Indexed: 05/21/2023]
Abstract
Five species of invasive Aedes mosquitoes have recently become established in Europe: Ae. albopictus, Ae. aegypti, Ae. japonicus japonicus, Ae. koreicus and Ae. atropalpus. These mosquitoes are a serious nuisance for people and are also competent vectors for several exotic pathogens such as dengue and chikungunya viruses. As they are a growing public health concern, methods to control these mosquitoes need to be implemented to reduce their biting and their potential for disease transmission. There is a crucial need to evaluate methods as part of an integrated invasive mosquito species control strategy in different European countries, taking into account local Aedes infestations and European regulations. This review presents the control methods available or in development against invasive Aedes mosquitoes, with a particular focus on those that can be implemented in Europe. These control methods are divided into five categories: environmental (source reduction), mechanical (trapping), biological (e.g. copepods, Bacillus thuringiensis var. israelensis, Wolbachia), chemical (insect growth regulators, pyrethroids) and genetic (sterile insect technique and genetically modified mosquitoes). We discuss the effectiveness, ecological impact, sustainability and stage of development of each control method.
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Affiliation(s)
- Frédéric Baldacchino
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach (FEM), San Michele all'Adige, Italy
| | - Beniamino Caputo
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma 'Sapienza', Rome, Italy
| | - Fabrice Chandre
- Institut de Recherche pour le Développement (IRD), Unité Mixte de Recherche Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (UMR MIVEGEC), Laboratoire de Lutte contre les Insectes Nuisibles (LIN), Montpellier, France
| | | | - Alessandra della Torre
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma 'Sapienza', Rome, Italy
| | | | - Annapaola Rizzoli
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach (FEM), San Michele all'Adige, Italy
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Che-Mendoza A, Guillermo-May G, Herrera-Bojórquez J, Barrera-Pérez M, Dzul-Manzanilla F, Gutierrez-Castro C, Arredondo-Jiménez JI, Sánchez-Tejeda G, Vazquez-Prokopec G, Ranson H, Lenhart A, Sommerfeld J, McCall PJ, Kroeger A, Manrique-Saide P. Long-lasting insecticide-treated house screens and targeted treatment of productive breeding-sites for dengue vector control in Acapulco, Mexico. Trans R Soc Trop Med Hyg 2015; 109:106-15. [PMID: 25604761 PMCID: PMC4299524 DOI: 10.1093/trstmh/tru189] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Background Long-lasting insecticidal net screens (LLIS) fitted to domestic windows and doors in combination with targeted treatment (TT) of the most productive Aedes aegypti breeding sites were evaluated for their impact on dengue vector indices in a cluster-randomised trial in Mexico between 2011 and 2013. Methods Sequentially over 2 years, LLIS and TT were deployed in 10 treatment clusters (100 houses/cluster) and followed up over 24 months. Cross-sectional surveys quantified infestations of adult mosquitoes, immature stages at baseline (pre-intervention) and in four post-intervention samples at 6-monthly intervals. Identical surveys were carried out in 10 control clusters that received no treatment. Results LLIS clusters had significantly lower infestations compared to control clusters at 5 and 12 months after installation, as measured by adult (male and female) and pupal-based vector indices. After addition of TT to the intervention houses in intervention clusters, indices remained significantly lower in the treated clusters until 18 (immature and adult stage indices) and 24 months (adult indices only) post-intervention. Conclusions These safe, simple affordable vector control tools were well-accepted by study participants and are potentially suitable in many regions at risk from dengue worldwide.
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Affiliation(s)
- Azael Che-Mendoza
- Servicios de Salud de Yucatán, Gobierno del Estado de Yucatán, Mérida C.P. 97000, Mexico
| | | | | | | | | | | | | | - Gustavo Sánchez-Tejeda
- Centro Nacional de Programas Preventivos y Control de Enfermedades, Secretaria de Salud, Mexico
| | | | - Hilary Ranson
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Audrey Lenhart
- US Centers for Disease Control and Prevention, Atlanta, GA30329, USA
| | - Johannes Sommerfeld
- Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, 1211 Geneva 27, Switzerland
| | - Philip J McCall
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Axel Kroeger
- Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, 1211 Geneva 27, Switzerland
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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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García-Betancourt T, Higuera-Mendieta DR, González-Uribe C, Cortés S, Quintero J. Understanding Water Storage Practices of Urban Residents of an Endemic Dengue Area in Colombia: Perceptions, Rationale and Socio-Demographic Characteristics. PLoS One 2015; 10:e0129054. [PMID: 26061628 PMCID: PMC4465337 DOI: 10.1371/journal.pone.0129054] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 05/04/2015] [Indexed: 11/21/2022] Open
Abstract
INTRODUCTION The main preventive measure against dengue virus transmission is often based on actions to control Ae. Aegypti reproduction by targeting water containers of clean and stagnant water. Household water storage has received special attention in prevention strategies but the evidence about the rationale of this human practice is limited. The objective was to identify and describe water storage practices among residents of an urban area in Colombia (Girardot) and its association with reported perceptions, rationales and socio-demographic characteristics with a mixed methods approach. METHODS Knowledge, attitudes and practices and entomological surveys from 1,721 households and 26 semi-structured interviews were conducted among residents of Girardot and technicians of the local vector borne disease program. A multivariate analysis was performed to identify associations between a water storage practice and socio-demographic characteristics, and knowledge, attitudes and practices about dengue and immature forms of the vector, which were then triangulated with qualitative information. RESULTS Water storage is a cultural practice in Girardot. There are two main reasons for storage: The scarcity concern based on a long history of shortages of water in the region and the perception of high prices in water rates, contrary to what was reported by the local water company. The practice of water storage was associated with being a housewife (Inverse OR: 2.6, 95% CI 1.5 -4.3). The use of stored water depends on the type of container used, while water stored in alberca (Intra household cement basins) is mainly used for domestic cleaning chores, water in plastic containers is used for cooking. CONCLUSIONS It is essential to understand social practices that can increase or reduce the number of breeding sites of Ae. Aegypti. Identification of individuals who store water and the rationale of such storage allow a better understanding of the social dynamics that lead to water accumulation.
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Affiliation(s)
| | | | - Catalina González-Uribe
- Centro de Estudios e Investigación en Salud (CEIS), Fundación Santa Fe de Bogotá, Bogotá, Colombia
| | - Sebastian Cortés
- Centro de Estudios e Investigación en Salud (CEIS), Fundación Santa Fe de Bogotá, Bogotá, Colombia
| | - Juliana Quintero
- Centro de Estudios e Investigación en Salud (CEIS), Fundación Santa Fe de Bogotá, Bogotá, Colombia
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Snetselaar J, Andriessen R, Suer RA, Osinga AJ, Knols BG, Farenhorst M. Development and evaluation of a novel contamination device that targets multiple life-stages of Aedes aegypti. Parasit Vectors 2014; 7:200. [PMID: 24766772 PMCID: PMC4005817 DOI: 10.1186/1756-3305-7-200] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 03/31/2014] [Indexed: 11/30/2022] Open
Abstract
Background The increasing global threat of Dengue demands new and easily applicable vector control methods. Ovitraps provide a low-tech and inexpensive means to combat Dengue vectors. Here we describe the development and optimization process of a novel contamination device that targets multiple life-stages of the Aedes aegypti mosquito. Special focus is directed to the diverse array of control agents deployed in this trap, covering adulticidal, larvicidal and autodissemination impacts. Methods Different trap prototypes and their parts are described, including a floater to contaminate alighting gravid mosquitoes. The attractiveness of the trap, different odor lures and floater design were studied using fluorescent powder adhering to mosquito legs and via choice tests. We demonstrate the mosquitocidal impacts of the control agents: a combination of the larvicide pyriproxyfen and the adulticidal fungus Beauveria bassiana. The impact of pyriproxyfen was determined in free-flight dissemination experiments. The effect on larval development inside the trap and in surrounding breeding sites was measured, as well as survival impacts on recaptured adults. Results The developmental process resulted in a design that consists of a black 3 Liter water-filled container with a ring-shaped floater supporting vertically placed gauze dusted with the control agents. On average, 90% of the mosquitoes in the fluorescence experiments made contact with the gauze on the floater. Studies on attractants indicated that a yeast-containing tablet was the most attractive odor lure. Furthermore, the fungus Beauveria bassiana was able to significantly increase mortality of the free-flying adults compared to controls. Dissemination of pyriproxyfen led to >90% larval mortality in alternative breeding sites and 100% larval mortality in the trap itself, against a control mortality of around 5%. Conclusion This ovitrap is a promising new tool in the battle against Dengue. It has proven to be attractive to Aedes aegypti mosquitoes and effective in contaminating these with Beauveria bassiana. Furthermore, we show that the larvicide pyriproxyfen is successfully disseminated to breeding sites close to the trap. Its low production and operating costs enable large scale deployment in Dengue-affected locations.
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Undesirable consequences of insecticide resistance following Aedes aegypti control activities due to a dengue outbreak. PLoS One 2014; 9:e92424. [PMID: 24676277 PMCID: PMC3968006 DOI: 10.1371/journal.pone.0092424] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 02/22/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND During a dengue outbreak with co-circulation of DENV-1 and -2 in the city of Boa Vista, one patient was diagnosed with DENV-4, a serotype supposed absent from Brazil for almost 30 years. The re-emergence of DENV-4 triggered the intensification of mechanical and chemical Aedes aegypti control activities in order to reduce vector density and avoid DENV-4 dissemination throughout the country. METHODS/PRINCIPAL FINDINGS Vector control activities consisted of (a) source reduction, (b) application of diflubenzuron against larvae and (c) vehicle-mounted space spraying of 2% deltamethrin to eliminate adults. Control activity efficacy was monitored by comparing the infestation levels and the number of eggs collected in ovitraps before and after interventions, performed in 22 Boa Vista districts, covering an area of ∼ 80% of the city and encompassing 56,837 dwellings. A total of 94,325 containers were eliminated or treated with diflubenzuron. The most frequently positive containers were small miscellaneous receptacles, which corresponded to 59% of all positive breeding sites. Insecticide resistance to deltamethrin was assessed before, during and after interventions by dose-response bioassays adopting WHO-based protocols. The intense use of the pyrethroid increased fourfold the resistance ratio of the local Ae. aegypti population only six months after the beginning of vector control. Curiously, this trend was also observed in the districts in which no deltamethrin was applied by the public health services. On the other hand, changes in the resistance ratio to the organophosphate temephos seemed less influenced by insecticide in Boa Vista. CONCLUSIONS Despite the intense effort, mosquito infestation levels were only slightly reduced. Besides, the median number of eggs in ovitraps remained unaltered after control activity intensification. The great and rapid increase in pyrethroid resistance levels of natural Ae. aegypti populations is discussed in the context of both public and domestic intensification of chemical control due to a dengue outbreak.
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Muzari OM, Adamczyk R, Davis J, Ritchie S, Devine G. Residual effectiveness of lambda-cyhalothrin harbourage sprays against foliage-resting mosquitoes in north Queensland. JOURNAL OF MEDICAL ENTOMOLOGY 2014; 51:444-449. [PMID: 24724295 DOI: 10.1603/me13141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The residual efficacy of lambda-cyhalothrin sprayed on foliage was evaluated against various mosquito species in sections of forest in Cairns, Queensland, Australia Weekly sweep-net collections in treated and untreated areas before and after spraying showed 87-100% reductions in mosquito numbers for the first 9 wk postspray. After that period, reductions fluctuated but remained >71% up to 14 wk posttreatment. Mosquito mortality ranged from 96 to 100% in contact bioassays of treated leaves during the 14 wk study. Our results demonstrate that spraying harborage vegetation with lambda-cyhalothrin is an extremely effective strategy for the control of sylvan and peridomestic mosquito species in tropical north Queensland.
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Chaves LF, Scott TW, Morrison AC, Takada T. Hot temperatures can force delayed mosquito outbreaks via sequential changes in Aedes aegypti demographic parameters in autocorrelated environments. Acta Trop 2014; 129:15-24. [PMID: 23537497 DOI: 10.1016/j.actatropica.2013.02.025] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 02/06/2013] [Accepted: 02/28/2013] [Indexed: 11/28/2022]
Abstract
Aedes aegypti L. (Diptera: Culicidae) is a common pantropical urban mosquito, vector of dengue, Yellow Fever and chikungunya viruses. Studies have shown Ae. aegypti abundance to be associated with environmental fluctuations, revealing patterns such as the occurrence of delayed mosquito outbreaks, i.e., sudden extraordinary increases in mosquito abundance following transient extreme high temperatures. Here, we use a two-stage (larvae and adults) matrix model to propose a mechanism for environmental signal canalization into demographic parameters of Ae. aegypti that could explain delayed high temperature induced mosquito outbreaks. We performed model simulations using parameters estimated from a weekly time series from Thailand, assuming either independent or autocorrelated environments. For autocorrelated environments, we found that long delays in the association between the onset of "hot" environments and mosquito outbreaks (10 weeks, as observed in Thailand) can be generated when "hot" environments sequentially trigger a larval survival decrease and over-compensatory fecundity increase, which lasts for the whole "hot" period, in conjunction with a larval survival increase followed by a fecundity decrease when the environment returns to "normal". This result was not observed for independent environments. Finally, we discuss our results implications for prospective entomological research and vector management under changing environments.
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Affiliation(s)
- Luis Fernando Chaves
- Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, P.O. Box 304-3000, Heredia, Costa Rica; Graduate School of Environmental Sciences, Hokkaido University, Sapporo 060-0810, Japan.
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Unlu I, Farajollahi A, Strickman D, Fonseca DM. Crouching tiger, hidden trouble: urban sources of Aedes albopictus (Diptera: Culicidae) refractory to source-reduction. PLoS One 2013; 8:e77999. [PMID: 24167593 PMCID: PMC3805523 DOI: 10.1371/journal.pone.0077999] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 09/06/2013] [Indexed: 11/28/2022] Open
Abstract
Our ultimate objective is to design cost-effective control strategies for Aedes albopictus, the Asian tiger mosquito, an important urban nuisance and disease vector that expanded worldwide during the last 40 years. We conducted mosquito larval surveys from May through October 2009 in the City of Trenton, New Jersey, USA, while performing intensive monthly source-reduction campaigns that involved removing, emptying, or treating all accessible containers with larvicides and pupicides. We examined patterns of occurrence of Ae. albopictus and Culex pipiens, another urban mosquito, among different container types by comparing observed and expected number of positive containers of each type. Expected use was based on the relative frequency of each container type in the environment. Aedes albopictus larvae and pupae were found significantly more often than expected in medium volumes of water in buckets and plant saucers but were rarely collected in small volumes of water found in trash items such as discarded cups and cans. They were also absent from large volumes of water such as in abandoned swimming pools and catch basins, although we consistently collected Cx. pipiens from those habitats. The frequency of Ae. albopictus in tires indicated rapid and extensive use of these ubiquitous urban containers. Standard larval-based indices did not correlate with adult catches in BG-Sentinel traps, but when based only on Ae. albopictus key containers (buckets, plant saucers, equipment with pockets of water, and tires) they did. Although we found that only 1.2% of the 20,039 water-holding containers examined contained immature Ae. albopictus (5.3% if only key containers were counted), adult populations were still above nuisance action thresholds six times during the 2009 mosquito season. We conclude that in urban New Jersey, effective source reduction for Ae. albopictus control will require scrupulous and repeated cleaning or treatment of everyday use containers and extensive homeowner collaboration.
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Affiliation(s)
- Isik Unlu
- Center for Vector Biology, Rutgers University, New Brunswick, New Jersey, United States of America
- Mercer County Mosquito Control, West Trenton, New Jersey, United States of America
| | - Ary Farajollahi
- Center for Vector Biology, Rutgers University, New Brunswick, New Jersey, United States of America
- Mercer County Mosquito Control, West Trenton, New Jersey, United States of America
| | - Daniel Strickman
- USDA Agricultural Research Service, Office of National Programs, Beltsville, Maryland, United States of America
| | - Dina M. Fonseca
- Center for Vector Biology, Rutgers University, New Brunswick, New Jersey, United States of America
- * E-mail:
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Public acceptance and willingness-to-pay for a future dengue vaccine: a community-based survey in Bandung, Indonesia. PLoS Negl Trop Dis 2013; 7:e2427. [PMID: 24069482 PMCID: PMC3777870 DOI: 10.1371/journal.pntd.0002427] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 08/02/2013] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND All four serotypes of dengue virus are endemic in Indonesia, where the population at risk for infection exceeds 200 million people. Despite continuous control efforts that were initiated more than four decades ago, Indonesia still suffers from multi-annual cycles of dengue outbreak and dengue remains as a major public health problem. Dengue vaccines have been viewed as a promising solution for controlling dengue in Indonesia, but thus far its potential acceptability has not been assessed. METHODOLOGY/PRINCIPAL FINDINGS We conducted a household survey in the city of Bandung, Indonesia by administering a questionnaire to examine (i) acceptance of a hypothetical pediatric dengue vaccine; (ii) participant's willingness-to-pay (WTP) for the vaccine, had it not been provided for free; and (iii) whether people think vector control would be unnecessary if the vaccine was available. A proportional odds model and an interval regression model were employed to identify determinants of acceptance and WTP, respectively. We demonstrated that out of 500 heads of household being interviewed, 94.2% would agree to vaccinate their children with the vaccine. Of all participants, 94.6% were willing to pay for the vaccine with a median WTP of US$1.94. In addition, 7.2% stated that vector control would not be necessary had there been a dengue vaccination program. CONCLUSIONS/SIGNIFICANCE Our results suggest that future dengue vaccines can have a very high uptake even when delivered through the private market. This, however, can be influenced by vaccine characteristics and price. In addition, reduction in community vector control efforts may be observed following vaccine introduction but its potential impact in the transmission of dengue and other vector-borne diseases requires further study.
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Schafrick NH, Milbrath MO, Berrocal VJ, Wilson ML, Eisenberg JNS. Spatial clustering of Aedes aegypti related to breeding container characteristics in Coastal Ecuador: implications for dengue control. Am J Trop Med Hyg 2013; 89:758-65. [PMID: 24002483 DOI: 10.4269/ajtmh.12-0485] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Mosquito management within households remains central to the control of dengue virus transmission. An important factor in these management decisions is the spatial clustering of Aedes aegypti. We measured spatial clustering of Ae. aegypti in the town of Borbón, Ecuador and assessed what characteristics of breeding containers influenced the clustering. We used logistic regression to assess the spatial extent of that clustering. We found strong evidence for juvenile mosquito clustering within 20 m and for adult mosquito clustering within 10 m, and stronger clustering associations for containers ≥ 40 L than those < 40 L. Aedes aegypti clusters persisted after adjusting for various container characteristics, suggesting that patterns are likely attributable to short dispersal distances rather than shared characteristics of containers in cluster areas. These findings have implications for targeting Ae. aegypti control efforts.
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Affiliation(s)
- Nathaniel H Schafrick
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan; Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, Michigan; Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, Michigan
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Valença MA, Marteis LS, Steffler LM, Silva AM, Santos RLC. Dynamics and characterization of Aedes aegypti (L.) (Diptera: Culicidae) key breeding sites. NEOTROPICAL ENTOMOLOGY 2013; 42:311-316. [PMID: 23949815 DOI: 10.1007/s13744-013-0118-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 01/30/2013] [Indexed: 06/02/2023]
Abstract
The present study aimed to analyze the dynamics of containers used as breeding sites by Aedes aegypti (L.) in the city of Aracaju, SE, one of the Northeast Brazilian states. A total of three entomological surveys were performed during different precipitation levels. Breeding sites were categorized according to their function into storage, disposable containers, and reusable containers. "Mean number of pupae" and "frequency of each type of breeding site" were the criteria considered to identify key breeding sites. House index and Breteau index were calculated in each survey. A total of 3,647 water reservoirs were found, of which 220 were breeding sites, where 22,880 immature forms were identified. There were no differences in the mean number of larvae of several types of breeding sites and in the number of larvae among surveys. Larval indices showed a reduction in the second visit, but with no effect on adult occurrence when the number of pupae was considered. Key breeding sites resulted from containers used for water storage. The area studied showed conditions favorable to a new epidemic of dengue fever.
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Affiliation(s)
- M A Valença
- Secretaria de Estado da Educação, Sergipe, Brasil
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Sylvestre G, Gandini M, Maciel-de-Freitas R. Age-dependent effects of oral infection with dengue virus on Aedes aegypti (Diptera: Culicidae) feeding behavior, survival, oviposition success and fecundity. PLoS One 2013; 8:e59933. [PMID: 23555838 PMCID: PMC3612067 DOI: 10.1371/journal.pone.0059933] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 02/20/2013] [Indexed: 11/18/2022] Open
Abstract
Background Aedes aegypti is the main vector of dengue, a disease that is increasing its geographical range as well as incidence rates. Despite its public health importance, the effect of dengue virus (DENV) on some mosquito traits remains unknown. Here, we investigated the impact of DENV-2 infection on the feeding behavior, survival, oviposition success and fecundity of Ae. aegypti females. Methods/Principal Findings After orally-challenging Ae. aegypti females with a DENV-2 strain using a membrane feeder, we monitored the feeding behavior, survival, oviposition success and fecundity throughout the mosquito lifespan. We observed an age-dependent cost of DENV infection on mosquito feeding behavior and fecundity. Infected individuals took more time to ingest blood from anesthetized mice in the 2nd and 3rd weeks post-infection, and also longer overall blood-feeding times in the 3rd week post-infection, when females were around 20 days old. Often, infected Ae. aegypti females did not lay eggs and when they were laid, smaller number of eggs were laid compared to uninfected controls. A reduction in the number of eggs laid per female was evident starting on the 3rd week post-infection. DENV-2 negatively affected mosquito lifespan, since overall the longevity of infected females was halved compared to that of the uninfected control group. Conclusions The DENV-2 strain tested significantly affected Ae. aegypti traits directly correlated with vectorial capacity or mosquito population density, such as feeding behavior, survival, fecundity and oviposition success. Infected mosquitoes spent more time ingesting blood, had reduced lifespan, laid eggs less frequently, and when they did lay eggs, the clutches were smaller than uninfected mosquitoes.
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Affiliation(s)
- Gabriel Sylvestre
- Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz - Fiocruz, Rio de Janeiro, Brazil
| | - Mariana Gandini
- Laboratório de Imunologia Viral, Instituto Oswaldo Cruz - Fiocruz, Fiocruz, Rio de Janeiro, Brazil
| | - Rafael Maciel-de-Freitas
- Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz - Fiocruz, Rio de Janeiro, Brazil
- * E-mail:
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David MR, Ribeiro GS, Freitas RMD. Bionomics of Culex quinquefasciatus within urban areas of Rio de Janeiro, Southeastern Brazil. Rev Saude Publica 2012; 46:858-65. [DOI: 10.1590/s0034-89102012000500013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 03/25/2012] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE: To evaluate density, parity rates, daily survival and longevity of natural populations of Culex quinquefasciatus in three neighborhoods with distinct socio-economic and infrastructure profiles. METHODS: Mosquito collections of the Culex quinquefasciatus species were performed weekly during two four month periods, from August to November 2008 (spring) and March to June 2009 (fall), in a favela (slum), a suburban area and a middle class area of Rio de Janeiro, Southeastern Brazil. Collections were performed with backpack aspirators, in 20 randomly selected houses in each area per week, during 15-20 minutes per house. Ovaries were removed from captured females and classified as initial, intermediary or final stage. Furthermore, females were dissected for determination of parity based on the condition of the tracheal system. Mosquito survival rate and longevity were estimated on a per month basis for each neighborhood. RESULTS: We collected a total of 2,062 Culex quinquefasciatus, but monthly vector density was not correlated with temperature and rainfall. We dissected the ovaries of 625 Culex quinquefasciatus, and overall, there was a higher proportion of nulliparous females during the dryer months, while gravid females were more frequent in rainy months. In the middle class neighborhood, the parity rate reached up to 93.75% with survivorship of 0.979. Lower parity and survival rates were obtained in the suburban area (as low as 36.4% parity and 0.711 daily survival). Up to 84.7% of Culex quinquefasciatus females could survive the eight day period needed to complete West Nile Virus incubation. CONCLUSIONS: The survival rate of Culex quinquefasciatus varied significantly between the neighborhoods. This suggests that vectorial capacity and disease transmission risk may vary greatly between different urban areas, which is potentially useful information for vector control programs.
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Wong J, Morrison AC, Stoddard ST, Astete H, Chu YY, Baseer I, Scott TW. Linking oviposition site choice to offspring fitness in Aedes aegypti: consequences for targeted larval control of dengue vectors. PLoS Negl Trop Dis 2012; 6:e1632. [PMID: 22563512 PMCID: PMC3341338 DOI: 10.1371/journal.pntd.0001632] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 03/19/2012] [Indexed: 11/21/2022] Open
Abstract
Background Current Aedes aegypti larval control methods are often insufficient for preventing dengue epidemics. To improve control efficiency and cost-effectiveness, some advocate eliminating or treating only highly productive containers. The population-level outcome of this strategy, however, will depend on details of Ae. aegypti oviposition behavior. Methodology/Principal Findings We simultaneously monitored female oviposition and juvenile development in 80 experimental containers located across 20 houses in Iquitos, Peru, to test the hypothesis that Ae. aegypti oviposit preferentially in sites with the greatest potential for maximizing offspring fitness. Females consistently laid more eggs in large vs. small containers (β = 9.18, p<0.001), and in unmanaged vs. manually filled containers (β = 5.33, p<0.001). Using microsatellites to track the development of immature Ae. aegypti, we found a negative correlation between oviposition preference and pupation probability (β = −3.37, p<0.001). Body size of emerging adults was also negatively associated with the preferred oviposition site characteristics of large size (females: β = −0.19, p<0.001; males: β = −0.11, p = 0.002) and non-management (females: β = −0.17, p<0.001; males: β = −0.11, p<0.001). Inside a semi-field enclosure, we simulated a container elimination campaign targeting the most productive oviposition sites. Compared to the two post-intervention trials, egg batches were more clumped during the first pre-intervention trial (β = −0.17, P<0.001), but not the second (β = 0.01, p = 0.900). Overall, when preferred containers were unavailable, the probability that any given container received eggs increased (β = 1.36, p<0.001). Conclusions/Significance Ae. aegypti oviposition site choice can contribute to population regulation by limiting the production and size of adults. Targeted larval control strategies may unintentionally lead to dispersion of eggs among suitable, but previously unoccupied or under-utilized containers. We recommend integrating targeted larval control measures with other strategies that leverage selective oviposition behavior, such as luring ovipositing females to gravid traps or egg sinks. Controlling the mosquito Aedes aegypti, the predominant dengue vector, requires understanding the ecological and behavioral factors that influence population abundance. Females of several mosquito species are able to identify high-quality egg-laying sites, resulting in enhanced offspring development and survival, and ultimately promoting population growth. Here, the authors investigated egg-laying decisions of Ae. aegypti. Paradoxically, they found that larval survival and development were poorest in the containers females most often selected for egg deposition. Thus, egg-laying decisions may contribute to crowding of larvae and play a role in regulating mosquito populations. The authors also tested whether removal of the containers producing the most adult mosquitoes, a World Health Organization-recommended dengue prevention strategy, changes the pattern of how females allocate their eggs. Elimination of the most productive containers led to a more even distribution of eggs in one trial, but not another. These results suggest that behavioral adjustments by egg-laying females may lessen the effectiveness of a common mosquito control tactic. The authors advocate incorporating control strategies that take advantage of the natural egg-laying preferences of this vector species, such as luring egg-laying females to traps or places where their eggs will accumulate, but not develop.
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Affiliation(s)
- Jacklyn Wong
- Department of Entomology, University of California Davis, Davis, California, United States of America.
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Application of mosquito—proof water containers in the reduction of dengue mosquito population in a dengue endemic province of Vietnam. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2011. [DOI: 10.1016/s2222-1808(11)60063-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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