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Ippoliti C, Bonicelli L, De Ascentis M, Tora S, Di Lorenzo A, d’Alessio SG, Porrello A, Bonanni A, Cioci D, Goffredo M, Calderara S, Conte A. Spotting Culex pipiens from satellite: modeling habitat suitability in central Italy using Sentinel-2 and deep learning techniques. Front Vet Sci 2024; 11:1383320. [PMID: 39027906 PMCID: PMC11256216 DOI: 10.3389/fvets.2024.1383320] [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: 02/07/2024] [Accepted: 06/05/2024] [Indexed: 07/20/2024] Open
Abstract
Culex pipiens, an important vector of many vector borne diseases, is a species capable to feeding on a wide variety of hosts and adapting to different environments. To predict the potential distribution of Cx. pipiens in central Italy, this study integrated presence/absence data from a four-year entomological survey (2019-2022) carried out in the Abruzzo and Molise regions, with a datacube of spectral bands acquired by Sentinel-2 satellites, as patches of 224 × 224 pixels of 20 meters spatial resolution around each site and for each satellite revisit time. We investigated three scenarios: the baseline model, which considers the environmental conditions at the time of collection; the multitemporal model, focusing on conditions in the 2 months preceding the collection; and the MultiAdjacency Graph Attention Network (MAGAT) model, which accounts for similarities in temperature and nearby sites using a graph architecture. For the baseline scenario, a deep convolutional neural network (DCNN) analyzed a single multi-band Sentinel-2 image. The DCNN in the multitemporal model extracted temporal patterns from a sequence of 10 multispectral images; the MAGAT model incorporated spatial and climatic relationships among sites through a graph neural network aggregation method. For all models, we also evaluated temporal lags between the multi-band Earth Observation datacube date of acquisition and the mosquito collection, from 0 to 50 days. The study encompassed a total of 2,555 entomological collections, and 108,064 images (patches) at 20 meters spatial resolution. The baseline model achieved an F1 score higher than 75.8% for any temporal lag, which increased up to 81.4% with the multitemporal model. The MAGAT model recorded the highest F1 score of 80.9%. The study confirms the widespread presence of Cx. pipiens throughout the majority of the surveyed area. Utilizing only Sentinel-2 spectral bands, the models effectively capture early in advance the temporal patterns of the mosquito population, offering valuable insights for directing surveillance activities during the vector season. The methodology developed in this study can be scaled up to the national territory and extended to other vectors, in order to support the Ministry of Health in the surveillance and control strategies for the vectors and the diseases they transmit.
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Affiliation(s)
- Carla Ippoliti
- Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise “G. Caporale”, Teramo, Italy
| | - Lorenzo Bonicelli
- Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Modena, Italy
| | - Matteo De Ascentis
- Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise “G. Caporale”, Teramo, Italy
| | - Susanna Tora
- Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise “G. Caporale”, Teramo, Italy
| | - Alessio Di Lorenzo
- Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise “G. Caporale”, Teramo, Italy
| | | | - Angelo Porrello
- Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Modena, Italy
| | - Americo Bonanni
- Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise “G. Caporale”, Teramo, Italy
| | - Daniela Cioci
- Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise “G. Caporale”, Teramo, Italy
| | - Maria Goffredo
- Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise “G. Caporale”, Teramo, Italy
| | - Simone Calderara
- Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Modena, Italy
| | - Annamaria Conte
- Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise “G. Caporale”, Teramo, Italy
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Krol L, Remmerswaal L, Groen M, van der Beek JG, Sikkema RS, Dellar M, van Bodegom PM, Geerling GW, Schrama M. Landscape level associations between birds, mosquitoes and microclimates: possible consequences for disease transmission? Parasit Vectors 2024; 17:156. [PMID: 38532512 DOI: 10.1186/s13071-024-06239-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 03/06/2024] [Indexed: 03/28/2024] Open
Abstract
BACKGROUND Mosquito-borne diseases are on the rise. While climatic factors have been linked to disease occurrences, they do not explain the non-random spatial distribution in disease outbreaks. Landscape-related factors, such as vegetation structure, likely play a crucial but hitherto unquantified role. METHODS We explored how three critically important factors that are associated with mosquito-borne disease outbreaks: microclimate, mosquito abundance and bird communities, vary at the landscape scale. We compared the co-occurrence of these three factors in two contrasting habitat types (forest versus grassland) across five rural locations in the central part of the Netherlands between June and September 2021. RESULTS Our results show that forest patches provide a more sheltered microclimate, and a higher overall abundance of birds. When accounting for differences in landscape characteristics, we also observed that the number of mosquitoes was higher in isolated forest patches. CONCLUSIONS Our findings indicate that, at the landscape scale, variation in tree cover coincides with suitable microclimate and high Culex pipiens and bird abundance. Overall, these factors can help understand the non-random spatial distribution of mosquito-borne disease outbreaks.
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Affiliation(s)
- Louie Krol
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands.
- Deltares, Daltonlaan 600, Utrecht, The Netherlands.
| | - Laure Remmerswaal
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
| | - Marvin Groen
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
| | - Jordy G van der Beek
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
- Naturalis Biodiversity Center, Leiden, The Netherlands
| | - Reina S Sikkema
- Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Martha Dellar
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
- Deltares, Daltonlaan 600, Utrecht, The Netherlands
| | - Peter M van Bodegom
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
| | - Gertjan W Geerling
- Deltares, Daltonlaan 600, Utrecht, The Netherlands
- Department of Environmental Science, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| | - Maarten Schrama
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
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Giesen C, Herrador Z, Fernandez B, Figuerola J, Gangoso L, Vazquez A, Gómez-Barroso D. A systematic review of environmental factors related to WNV circulation in European and Mediterranean countries. One Health 2023. [DOI: 10.1016/j.onehlt.2022.100478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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4
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Brugueras S, Fernández-Martínez B, Martínez-de la Puente J, Figuerola J, Porro TM, Rius C, Larrauri A, Gómez-Barroso D. Environmental drivers, climate change and emergent diseases transmitted by mosquitoes and their vectors in southern Europe: A systematic review. ENVIRONMENTAL RESEARCH 2020; 191:110038. [PMID: 32810503 DOI: 10.1016/j.envres.2020.110038] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 07/02/2020] [Accepted: 08/04/2020] [Indexed: 06/11/2023]
Abstract
Mosquito borne diseases are a group of infections that affect humans. Emerging or reemerging diseases are those that (re)occur in regions, groups or hosts that were previously free from these diseases: dengue virus; chikungunya virus; Zika virus; West Nile fever and malaria. In Europe, these infections are mostly imported; however, due to the presence of competent mosquitoes and the number of trips both to and from endemic areas, these pathogens are potentially emergent or re-emergent. Present and future climatic conditions, as well as meteorological, environmental and demographic aspects are risk factors for the distribution of different vectors and/or diseases. This review aimed to identify and analyze the existing literature on the transmission of mosquito borne diseases and those factors potentially affecting their transmission risk of them in six southern European countries with similar environmental conditions: Croatia, France, Greece, Italy, Portugal and Spain. In addition, we would identify those factors potentially affecting the (re)introduction or spread of mosquito vectors. This task has been undertaken with a focus on the environmental and climatic factors, including the effects of climate change. We undertook a systematic review of the vectors, diseases and their associations with climactic and environmental factors in European countries of the Mediterranean region. We followed the PRISMA guidelines and used explicit and systematic methods to identify, select and critically evaluate the studies which were relevant to the topic. We identified 1302 articles in the first search of the databases. Of those, 160 were selected for full-text review. The final data set included 61 articles published between 2000 and 2017.39.3% of the papers were related with dengue, chikungunya and Zika virus or their vectors. Temperature, precipitation and population density were key factors among others. 32.8% studied West Nile virus and its vectors, being temperature, precipitation and NDVI the most frequently used variables. Malaria have been studied in 23% of the articles, with temperature, precipitation and presence of water indexes as the most used variables. The number of publications focused on mosquito borne diseases is increasing in recent years, reflecting the increased interest in that diseases in southern European countries. Climatic and environmental variables are key factors on mosquitoes' distribution and to show the risk of emergence and/or spread of emergent diseases and to study the spatial changes in that distributions.
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Affiliation(s)
- Silvia Brugueras
- Agencia de Salud Pública de Barcelona, Pl. Lesseps, 1, 08023, Barcelona, Spain; CIBER de Epidemiología y Salud Pública, Calle Monforte de Lemos 5, 28029, Madrid, Spain
| | - Beatriz Fernández-Martínez
- Centro Nacional de Epidemiología, Instituto de Salud Carlos III, Calle Monforte de Lemos 5, 28029, Madrid, Spain; CIBER de Epidemiología y Salud Pública, Calle Monforte de Lemos 5, 28029, Madrid, Spain
| | - Josué Martínez-de la Puente
- Estación Biológica de Doñana (EBD-CSIC), Calle Américo Vespucio, 26, E-41092, Sevilla, Spain; CIBER de Epidemiología y Salud Pública, Calle Monforte de Lemos 5, 28029, Madrid, Spain
| | - Jordi Figuerola
- Estación Biológica de Doñana (EBD-CSIC), Calle Américo Vespucio, 26, E-41092, Sevilla, Spain; CIBER de Epidemiología y Salud Pública, Calle Monforte de Lemos 5, 28029, Madrid, Spain
| | - Tomas Montalvo Porro
- Agencia de Salud Pública de Barcelona, Pl. Lesseps, 1, 08023, Barcelona, Spain; CIBER de Epidemiología y Salud Pública, Calle Monforte de Lemos 5, 28029, Madrid, Spain
| | - Cristina Rius
- Agencia de Salud Pública de Barcelona, Pl. Lesseps, 1, 08023, Barcelona, Spain; CIBER de Epidemiología y Salud Pública, Calle Monforte de Lemos 5, 28029, Madrid, Spain
| | - Amparo Larrauri
- Centro Nacional de Epidemiología, Instituto de Salud Carlos III, Calle Monforte de Lemos 5, 28029, Madrid, Spain; CIBER de Epidemiología y Salud Pública, Calle Monforte de Lemos 5, 28029, Madrid, Spain
| | - Diana Gómez-Barroso
- Centro Nacional de Epidemiología, Instituto de Salud Carlos III, Calle Monforte de Lemos 5, 28029, Madrid, Spain; CIBER de Epidemiología y Salud Pública, Calle Monforte de Lemos 5, 28029, Madrid, Spain.
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Fornasiero D, Mazzucato M, Barbujani M, Montarsi F, Capelli G, Mulatti P. Inter-annual variability of the effects of intrinsic and extrinsic drivers affecting West Nile virus vector Culex pipiens population dynamics in northeastern Italy. Parasit Vectors 2020; 13:271. [PMID: 32471479 PMCID: PMC7260749 DOI: 10.1186/s13071-020-04143-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 05/21/2020] [Indexed: 11/10/2022] Open
Abstract
Background Vector-borne infectious diseases (VBDs) represent a major public health concern worldwide. Among VBDs, West Nile virus (WNV) showed an increasingly wider spread in temperate regions of Europe, including Italy. During the last decade, WNV outbreaks have been recurrently reported in mosquitoes, horses, wild birds, and humans, showing great variability in the temporal and spatial distribution pattern. Due to the complexity of the environment–host–vector–pathogen interaction and the incomplete understanding of the epidemiological pattern of the disease, WNV occurrences can be difficult to predict. The analyses of ecological drivers responsible for the earlier WNV reactivation and transmission are pivotal; in particular, variations in the vector population dynamics may represent a key point of the recent success of WNV and, more in general, of the VBDs. Methods We investigated the variations of Culex pipiens population abundance using environmental, climatic and trapping data obtained over nine years (2010 to 2018) through the WNV entomological surveillance programme implemented in northeastern Italy. An information theoretic approach (IT-AICc) and model-averaging algorithms were implemented to examine the relationship between the seasonal mosquito population growth rates and both intrinsic (e.g. intraspecific competition) and extrinsic (e.g. environmental and climatic variables) predictors, to identify the most significant combinations of variables outlining the Cx. pipiens population dynamics. Results Population abundance (proxy for intraspecific competition) and length of daylight were the predominant factors regulating the mosquito population dynamics; however, other drivers encompassing environmental and climatic variables also had a significant impact, although sometimes counterintuitive and not univocal. The analyses of the single-year datasets, and the comparison with the results obtained from the overall model (all data available from 2010 to 2018), highlighted remarkable differences in coefficients magnitude, sign and significance. These outcomes indicate that different combinations of factors might have distinctive, and sometimes divergent, effects on mosquito population dynamics. Conclusions A more realistic acquaintance of the intrinsic and extrinsic mechanisms of mosquito population fluctuations in relation to continuous changes in environmental and climatic conditions is paramount to properly reinforce VBDs risk-based surveillance activities, to plan targeted density control measures and to implement effective early detection programmes.![]()
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Affiliation(s)
- Diletta Fornasiero
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, 35020, Legnaro, Padua, Italy.
| | - Matteo Mazzucato
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, 35020, Legnaro, Padua, Italy
| | - Marco Barbujani
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, 35020, Legnaro, Padua, Italy
| | - Fabrizio Montarsi
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, 35020, Legnaro, Padua, Italy
| | - Gioia Capelli
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, 35020, Legnaro, Padua, Italy
| | - Paolo Mulatti
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, 35020, Legnaro, Padua, Italy
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6
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Karki S, Brown WM, Uelmen J, Ruiz MO, Smith RL. The drivers of West Nile virus human illness in the Chicago, Illinois, USA area: Fine scale dynamic effects of weather, mosquito infection, social, and biological conditions. PLoS One 2020; 15:e0227160. [PMID: 32437363 PMCID: PMC7241786 DOI: 10.1371/journal.pone.0227160] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/09/2020] [Indexed: 11/19/2022] Open
Abstract
West Nile virus (WNV) has consistently been reported to be associated with human cases of illness in the region near Chicago, Illinois. However, the number of reported cases of human illness varies across years, with intermittent outbreaks. Several dynamic factors, including temperature, rainfall, and infection status of vector mosquito populations, are responsible for much of these observed variations. However, local landscape structure and human demographic characteristics also play a key role. The geographic and temporal scales used to analyze such complex data affect the observed associations. Here, we used spatial and statistical modeling approaches to investigate the factors that drive the outcome of WNV human illness on fine temporal and spatial scales. Our approach included multi-level modeling of long-term weekly data from 2005 to 2016, with weekly measures of mosquito infection, human illness and weather combined with more stable landscape and demographic factors on the geographical scale of 1000m hexagons. We found that hot weather conditions, warm winters, and higher MIR in earlier weeks increased the probability of an area of having a WNV human case. Higher population and the proportion of urban light intensity in an area also increased the probability of observing a WNV human case. A higher proportion of open water sources, percentage of grass land, deciduous forests, and housing built post 1990 decreased the probability of having a WNV case. Additionally, we found that cumulative positive mosquito pools up to 31 weeks can strongly predict the total annual human WNV cases in the Chicago region. This study helped us to improve our understanding of the fine-scale drivers of spatiotemporal variability of human WNV cases.
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Affiliation(s)
- Surendra Karki
- Department of Pathobiology, University of Illinois, Urbana-Champaign, Urbana, Illinois, United States of America
| | - William M. Brown
- Department of Pathobiology, University of Illinois, Urbana-Champaign, Urbana, Illinois, United States of America
| | - John Uelmen
- Department of Pathobiology, University of Illinois, Urbana-Champaign, Urbana, Illinois, United States of America
| | - Marilyn O’Hara Ruiz
- Department of Pathobiology, University of Illinois, Urbana-Champaign, Urbana, Illinois, United States of America
| | - Rebecca Lee Smith
- Department of Pathobiology, University of Illinois, Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail:
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Bhowmick S, Gethmann J, Conraths FJ, Sokolov IM, Lentz HHK. Locally temperature - driven mathematical model of West Nile virus spread in Germany. J Theor Biol 2019; 488:110117. [PMID: 31866397 DOI: 10.1016/j.jtbi.2019.110117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 11/22/2019] [Accepted: 12/12/2019] [Indexed: 01/06/2023]
Abstract
West Nile virus (WNV) is an arthropod-borne virus (arbovirus) transmitted by the bites of infected mosquitoes. WNV can also infect horses and humans, where it may cause serious illness and can be fatal. Birds are the natural reservoir, and humans, equines and probably other mammals are dead-end hosts. In 2018, WNV occurred for the first time in Germany, affecting birds and horses. Seroconversion of an exposed veterinarian has also been reported. It is therefore of importance to evaluate the circumstances, under which WNV may establish in Germany as a whole or in particular favourable regions. In our current work, we formulate a dynamic model to describe the spreading process of West Nile virus in the presence of migratory birds. To investigate the possible role of migratory birds in the dissemination of WNV in Germany, we include the recurring presence of migratory birds through a mechanistic ordinary differential equations (ODE) model system. We also perform a sensitivity analysis of the infection curves. Seasonal impacts are also taken into consideration. As result, we present an analytical expression for the basic reproduction number R0. We find that after introducing WNV into Germany, R0 will be above the critical value in many regions of the country. Furthermore, we observe that in the south of Germany, the disease reoccurs in the following season after the introduction. We include a potential distribution map associated with WNV cases in Germany to illustrate our findings in a spatial scale.
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Affiliation(s)
- Suman Bhowmick
- Friedrich-Loeffler-Institut, Institute of Epidemiology, Südufer 10, Greifswald 17493, Germany; Institute of Physics, Humboldt University of Berlin, Newtonstraße 15, Berlin 12489, Germany
| | - Jörn Gethmann
- Friedrich-Loeffler-Institut, Institute of Epidemiology, Südufer 10, Greifswald 17493, Germany
| | - Franz J Conraths
- Friedrich-Loeffler-Institut, Institute of Epidemiology, Südufer 10, Greifswald 17493, Germany
| | - Igor M Sokolov
- Institute of Physics, Humboldt University of Berlin, Newtonstraße 15, Berlin 12489, Germany
| | - Hartmut H K Lentz
- Friedrich-Loeffler-Institut, Institute of Epidemiology, Südufer 10, Greifswald 17493, Germany.
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Krol L, Gorsich EE, Hunting ER, Govender D, van Bodegom PM, Schrama M. Eutrophication governs predator-prey interactions and temperature effects in Aedes aegypti populations. Parasit Vectors 2019; 12:179. [PMID: 31014388 PMCID: PMC6480876 DOI: 10.1186/s13071-019-3431-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 04/04/2019] [Indexed: 12/04/2022] Open
Abstract
Background Mosquito population dynamics are driven by large-scale (e.g. climatological) and small-scale (e.g. ecological) factors. While these factors are known to independently influence mosquito populations, it remains uncertain how drivers that simultaneously operate under natural conditions interact to influence mosquito populations. We, therefore, developed a well-controlled outdoor experiment to assess the interactive effects of two ecological drivers, predation and nutrient availability, on mosquito life history traits under multiple temperature regimes. Methods We conducted a temperature-controlled mesocosm experiment in Kruger National Park, South Africa, with the yellow fever mosquito, Aedes aegypti. We investigated how larval survival, emergence and development rates were impacted by the presence of a locally-common invertebrate predator (backswimmers Anisops varia Fieber (Notonectidae: Hemiptera), nutrient availability (oligotrophic vs eutrophic, reflecting field conditions), water temperature, and interactions between each driver. Results We observed that the effects of predation and temperature both depended on eutrophication. Predation caused lower adult emergence in oligotrophic conditions but higher emergence under eutrophic conditions. Higher temperatures caused faster larval development rates in eutrophic but not oligotrophic conditions. Conclusions Our study shows that ecological bottom-up and top-down drivers strongly and interactively govern mosquito life history traits for Ae. aegypti populations. Specifically, we show that eutrophication can inversely affect predator–prey interactions and mediate the effect of temperature on mosquito survival and development rates. Hence, our results suggest that nutrient pollution can overrule biological constraints on natural mosquito populations and highlights the importance of studying multiple factors. Electronic supplementary material The online version of this article (10.1186/s13071-019-3431-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Louie Krol
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands.,Naturalis Biodiversity Centre, Leiden, The Netherlands
| | - Erin E Gorsich
- The Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research, University of Warwick, Coventry, UK.,School of Life Sciences, University of Warwick, Coventry, UK
| | - Ellard R Hunting
- School of Biological Sciences, University of Bristol, Bristol, UK.,Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Danny Govender
- Department of Paraclinical Sciences, University of Pretoria, Pretoria, South Africa.,Scientific Services Kruger National Park, Skukuza, South Africa
| | - Peter M van Bodegom
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
| | - Maarten Schrama
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands. .,Naturalis Biodiversity Centre, Leiden, The Netherlands.
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Ewing DA, Purse BV, Cobbold CA, Schäfer SM, White SM. Uncovering mechanisms behind mosquito seasonality by integrating mathematical models and daily empirical population data: Culex pipiens in the UK. Parasit Vectors 2019; 12:74. [PMID: 30732629 PMCID: PMC6367758 DOI: 10.1186/s13071-019-3321-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 01/28/2019] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Many mosquito-borne diseases exhibit substantial seasonality, due to strong links between environmental variables and vector and pathogen life-cycles. Further, a range of density-dependent and density-independent biotic and abiotic processes affect the phenology of mosquito populations, with potentially large knock-on effects for vector dynamics and disease transmission. Whilst it is understood that density-independent and density-dependent processes affect seasonal population levels, it is not clear how these interact temporally to shape the population peaks and troughs. Due to this, the paucity of high-resolution data for validation, and the difficulty of parameterizing density-dependent processes, models of vector dynamics may poorly estimate abundances, which has knock-on effects for our ability predict vector-borne disease outbreaks. RESULTS We present a rich dataset describing seasonal abundance patterns of each life stage of Culex pipiens, a widespread vector of West Nile virus, at a field site in southern England in 2015. Abundance of immature stages was measured three times per week, whilst adult traps were run four nights each week. This dataset is integrated with an existing delay-differential equation model predicting Cx. pipiens seasonal abundance to improve understanding of observed seasonal abundance patterns. At our field site, the outcome of our model fitting suggests interspecific predation on mosquito larvae and temperature-dependent larval mortality combine to act as the main sources of population regulation throughout the active season, whilst competition for resources is a relatively small source of larval mortality. CONCLUSIONS The model suggests that density-independent mortality and interspecific predation interact to shape patterns of mosquito seasonal abundance in a permanent aquatic habitat and we propose that competition for resources is likely to be important where periods of high rainfall create transient habitats. Further, we highlight the importance of challenging population abundance models with data from across all life stages of the species of interest if reliable inferences are to be drawn from these models, particularly when considering mosquito control and vector-borne disease transmission.
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Affiliation(s)
- David A. Ewing
- Centre for Ecology & Hydrology, Benson Lane, Crowmarsh Gifford, Wallingford, OX10 8BB UK
- Department of Mathematics and Statistics, University of Glasgow, University Place, Glasgow, G12 8QQ UK
- Present address: Biomathematics and Statistics Scotland, James Clerk Maxwell Building, Peter Guthrie Tate Road, The King’s Buildings, Edinburgh, EH9 3FD UK
| | - Bethan V. Purse
- Centre for Ecology & Hydrology, Benson Lane, Crowmarsh Gifford, Wallingford, OX10 8BB UK
| | - Christina A. Cobbold
- Department of Mathematics and Statistics, University of Glasgow, University Place, Glasgow, G12 8QQ UK
- The Boyd Orr Centre for Population and Ecosystem Health, University of Glasgow, University Avenue, Glasgow, G12 8QQ UK
| | - Stefanie M. Schäfer
- Centre for Ecology & Hydrology, Benson Lane, Crowmarsh Gifford, Wallingford, OX10 8BB UK
| | - Steven M. White
- Centre for Ecology & Hydrology, Benson Lane, Crowmarsh Gifford, Wallingford, OX10 8BB UK
- The Wolfson Centre for Mathematical Biology, Mathematical Institute, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG UK
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10
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Culler LE, Ayres MP, Virginia RA. Spatial heterogeneity in the abundance and fecundity of Arctic mosquitoes. Ecosphere 2018. [DOI: 10.1002/ecs2.2345] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- Lauren E. Culler
- Environmental Studies Program Dartmouth College 113 Steele Hall Hanover New Hampshire 03755 USA
- Institute of Arctic Studies The Dickey Center for International Understanding Dartmouth College 6214 Haldeman Center Hanover New Hampshire 03755 USA
- Department of Biological Sciences Dartmouth College 78 College Street Hanover New Hampshire 03755 USA
| | - Matthew P. Ayres
- Institute of Arctic Studies The Dickey Center for International Understanding Dartmouth College 6214 Haldeman Center Hanover New Hampshire 03755 USA
- Department of Biological Sciences Dartmouth College 78 College Street Hanover New Hampshire 03755 USA
| | - Ross A. Virginia
- Environmental Studies Program Dartmouth College 113 Steele Hall Hanover New Hampshire 03755 USA
- Institute of Arctic Studies The Dickey Center for International Understanding Dartmouth College 6214 Haldeman Center Hanover New Hampshire 03755 USA
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Ruget AS, Beck C, Gabassi A, Trevennec K, Lecollinet S, Chevalier V, Cappelle J. Japanese encephalitis circulation pattern in swine of northern Vietnam and consequences for swine's vaccination recommendations. Transbound Emerg Dis 2018; 65:1485-1492. [PMID: 29740970 DOI: 10.1111/tbed.12885] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Indexed: 11/28/2022]
Abstract
Japanese encephalitis (JE) is the largest worldwide cause of infectious encephalitis in humans and is caused by a mosquito-borne flavivirus. JE transmission cycle involves Culex mosquitoes, pigs and aquatic birds as principal vertebrate amplifying hosts. JE infection is responsible for reproductive disorder in pigs when occurring after sexual maturity. In tropical areas, JE is endemic and the majority of pigs get infected before the age of 6 months. However, in subtropical areas, pigs may be infected after sexual maturity and thus experience clinical signs, inducing economic loss. The study aimed at better characterizing the influence of seasonal temperature variations (through estimates of degree days, DD) on JE circulation in pigs in subtropical area and inferring on the potential impact on JE symptomatic infection in reproductive pigs. Six hundred and forty-one pig's sera sampled in northern Vietnam were analysed for Japanese encephalitis virus (JEV) by pan-flavivirus ELISA. A subset of 108 ELISA-positive samples, representative of each sampling occasion, were confirmed by JEV neutralization test compared with West Nile virus neutralization test. We modelled the seroprevalence of pigs according to a DD variable using a generalized additive model. We then predicted the age of infection in pigs according to their month of birth, using averaged temperature data over 10 years. The model predicts that only 80 percentage of pigs born between July and September will be protected against JEV when reaching sexual maturity contrary to the rest of the year when almost all pigs will seroconvert before sexual maturity. In subtropical area such as northern Vietnam, pigs could thus show symptomatic infection due to JE, and consequently reproductive disorders. Vaccination of future breeder pigs in epidemic areas could avoid the occurrence of JE-associated reproductive disorders.
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Affiliation(s)
- A-S Ruget
- Institut Pasteur du Cambodge, Epidemiology and Public Health Unit, Phnom Penh, Cambodia
| | - C Beck
- ANSES Animal Health Laboratory, EURL on equine diseases, UMR 1161 Virology, INRA, ANSES, ENVA, Maisons-Alfort, France
| | - A Gabassi
- Department of Virology, AP-HP, Hôpital Saint-Louis, University of Paris Diderot, Paris, France
| | | | - S Lecollinet
- ANSES Animal Health Laboratory, EURL on equine diseases, UMR 1161 Virology, INRA, ANSES, ENVA, Maisons-Alfort, France
| | - V Chevalier
- Institut Pasteur du Cambodge, Epidemiology and Public Health Unit, Phnom Penh, Cambodia.,CIRAD, UMR ASTRE, Montpellier, France.,UMR ASTRE, CIRAD, INRA, Université de Montpellier, Montpellier, France
| | - J Cappelle
- Institut Pasteur du Cambodge, Epidemiology and Public Health Unit, Phnom Penh, Cambodia.,CIRAD, UMR ASTRE, Montpellier, France.,UMR ASTRE, CIRAD, INRA, Université de Montpellier, Montpellier, France.,UMR EpiA, VetAgro Sup, INRA, Marcy l'étoile, France
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12
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Groen TA, L'Ambert G, Bellini R, Chaskopoulou A, Petric D, Zgomba M, Marrama L, Bicout DJ. Ecology of West Nile virus across four European countries: empirical modelling of the Culex pipiens abundance dynamics as a function of weather. Parasit Vectors 2017; 10:524. [PMID: 29070056 PMCID: PMC5657042 DOI: 10.1186/s13071-017-2484-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 10/17/2017] [Indexed: 11/23/2022] Open
Abstract
Background Culex pipiens is the major vector of West Nile virus in Europe, and is causing frequent outbreaks throughout the southern part of the continent. Proper empirical modelling of the population dynamics of this species can help in understanding West Nile virus epidemiology, optimizing vector surveillance and mosquito control efforts. But modelling results may differ from place to place. In this study we look at which type of models and weather variables can be consistently used across different locations. Methods Weekly mosquito trap collections from eight functional units located in France, Greece, Italy and Serbia for several years were combined. Additionally, rainfall, relative humidity and temperature were recorded. Correlations between lagged weather conditions and Cx. pipiens dynamics were analysed. Also seasonal autoregressive integrated moving-average (SARIMA) models were fitted to describe the temporal dynamics of Cx. pipiens and to check whether the weather variables could improve these models. Results Correlations were strongest between mean temperatures at short time lags, followed by relative humidity, most likely due to collinearity. Precipitation alone had weak correlations and inconsistent patterns across sites. SARIMA models could also make reasonable predictions, especially when longer time series of Cx. pipiens observations are available. Conclusions Average temperature was a consistently good predictor across sites. When only short time series (~ < 4 years) of observations are available, average temperature can therefore be used to model Cx. pipiens dynamics. When longer time series (~ > 4 years) are available, SARIMAs can provide better statistical descriptions of Cx. pipiens dynamics, without the need for further weather variables. This suggests that density dependence is also an important determinant of Cx. pipiens dynamics. Electronic supplementary material The online version of this article (10.1186/s13071-017-2484-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Thomas A Groen
- University of Twente, Faculty of Geo-Information Science and Earth Observation, PO, Box 217 7500 AE, Enschede, the Netherlands
| | - Gregory L'Ambert
- EID Mediterranee, 165 Avenue Paul Rimbaud, 34184, Montpellier, France
| | - Romeo Bellini
- Centro Agricoltura Ambiente "G. Nicoli", Via Argini Nord 3351, 40014, Crevalcore, Italy
| | - Alexandra Chaskopoulou
- USDA-ARS, European Biological Control Laboratory, Tsimiski 43, 54623, Thessaloniki, Greece
| | - Dusan Petric
- University of Novi Sad, Faculty of Agriculture, Laboratory for Medical Entomology, Trg D. Obradovica 8, Novi Sad, 21000, Serbia
| | - Marija Zgomba
- University of Novi Sad, Faculty of Agriculture, Laboratory for Medical Entomology, Trg D. Obradovica 8, Novi Sad, 21000, Serbia
| | - Laurence Marrama
- ECDC, European Centre for Disease Prevention and Control, Tomtebodavagen 11A, 17183, Stockholm, Sweden
| | - Dominique J Bicout
- Biomathematics and Epidemiology EPSP-TIMC, VetAgro Sup, Veterinary Campus of Lyon, F-69280, Marcy l'Etoile, France. .,Laue - Langevin Institute, Theory Group, F-38042, Grenoble cedex 9, France.
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13
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Schneeberger PHH, Pothier JF, Bühlmann A, Duffy B, Beuret C, Utzinger J, Frey JE. Development and evaluation of a bioinformatics approach for designing molecular assays for viral detection. PLoS One 2017; 12:e0178195. [PMID: 28542435 PMCID: PMC5444669 DOI: 10.1371/journal.pone.0178195] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 05/08/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Viruses belonging to the Flaviviridae and Bunyaviridae families show considerable genetic diversity. However, this diversity is not necessarily taken into account when developing diagnostic assays, which are often based on the pairwise alignment of a limited number of sequences. Our objective was to develop and evaluate a bioinformatics workflow addressing two recurrent issues of molecular assay design: (i) the high intraspecies genetic diversity in viruses and (ii) the potential for cross-reactivity with close relatives. METHODOLOGY The workflow developed herein was based on two consecutive BLASTn steps; the first was utilized to select highly conserved regions among the viral taxon of interest, and the second was employed to assess the degree of similarity of these highly-conserved regions to close relatives. Subsequently, the workflow was tested on a set of eight viral species, including various strains from the Flaviviridae and Bunyaviridae families. PRINCIPAL FINDINGS The genetic diversity ranges from as low as 0.45% variable sites over the complete genome of the Japanese encephalitis virus to more than 16% of variable sites on segment L of the Crimean-Congo hemorrhagic fever virus. Our proposed bioinformatics workflow allowed the selection-based on computing scores-of the best target for a diagnostic molecular assay for the eight viral species investigated. CONCLUSIONS/SIGNIFICANCE Our bioinformatics workflow allowed rapid selection of highly conserved and specific genomic fragments among the investigated viruses, while considering up to several hundred complete genomic sequences. The pertinence of this workflow will increase in parallel to the number of sequences made publicly available. We hypothesize that our workflow might be utilized to select diagnostic molecular markers for higher organisms with more complex genomes, provided the sequences are made available.
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Affiliation(s)
- Pierre H. H. Schneeberger
- Agroscope, Department of Methods Development and Analytics, Wädenswil, Switzerland
- Department of Virology, Spiez Laboratory, Federal Office for Civil Protection, Spiez, Switzerland
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
| | - Joël F. Pothier
- Zurich University of Applied Sciences (ZHAW), Institute of Natural Resource Sciences, Environmental Genomics and Systems Biology Research Group, Wädenswil, Switzerland
| | - Andreas Bühlmann
- Department of Foods of Plant Origin, Agroscope, Institute for Food Sciences IFS, Wädenswil, Switzerland
| | - Brion Duffy
- Zurich University of Applied Sciences (ZHAW), Institute of Natural Resource Sciences, Environmental Genomics and Systems Biology Research Group, Wädenswil, Switzerland
| | - Christian Beuret
- Department of Virology, Spiez Laboratory, Federal Office for Civil Protection, Spiez, Switzerland
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jürg E. Frey
- Agroscope, Department of Methods Development and Analytics, Wädenswil, Switzerland
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14
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Karki S, Hamer GL, Anderson TK, Goldberg TL, Kitron UD, Krebs BL, Walker ED, Ruiz MO. Effect of Trapping Methods, Weather, and Landscape on Estimates of the Culex Vector Mosquito Abundance. ENVIRONMENTAL HEALTH INSIGHTS 2016; 10:93-103. [PMID: 27375359 PMCID: PMC4918690 DOI: 10.4137/ehi.s33384] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 05/16/2016] [Accepted: 05/20/2016] [Indexed: 05/27/2023]
Abstract
The local abundance of Culex mosquitoes is a central factor adding to the risk of West Nile virus transmission, and vector abundance data influence public health decisions. This study evaluated differences in abundance estimates from mosquitoes trapped using two common methods: CO2-baited CDC light traps and infusion-baited gravid traps in suburban, Chicago, Illinois. On a weekly basis, the two methods were modestly correlated (r = 0.219) across 71 weeks over 4 years. Lagged weather conditions of up to four weeks were associated with the number of mosquitoes collected in light and gravid traps. Collections in light traps were higher with higher temperature in the same week, higher precipitation one, two, and four weeks before the week of trapping, and lower maximum average wind speed. Collections in gravid traps were higher with higher temperature in the same week and one week earlier, lower temperature four weeks earlier, and with higher precipitation two and four weeks earlier. Culex abundance estimates from light traps were significantly higher in semi-natural areas compared to residential areas, but abundance estimates from gravid traps did not vary by the landscape type. These results highlight the importance of the surveillance methods used in the assessment of local Culex abundance estimates. Measures of risk of exposure to West Nile virus should assess carefully how mosquito abundance has been estimated and integrated into assessments of transmission risk.
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Affiliation(s)
- Surendra Karki
- Department of Pathobiology, University of Illinois, Urbana-Champaign, IL, USA
| | - Gabriel L. Hamer
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Tavis K. Anderson
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA
| | - Tony L. Goldberg
- Department of Pathobiological Sciences, University of Wisconsin, Madison, WI, USA
| | - Uriel D. Kitron
- Department of Environmental Studies, Emory University, Atlanta, GA, USA
| | - Bethany L. Krebs
- Wellness and Animal Behavior Department, San Francisco Zoo, San Francisco, CA, USA
| | - Edward D. Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, Lansing, MI, USA
| | - Marilyn O. Ruiz
- Department of Pathobiology, University of Illinois, Urbana-Champaign, IL, USA
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15
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Marini G, Poletti P, Giacobini M, Pugliese A, Merler S, Rosà R. The Role of Climatic and Density Dependent Factors in Shaping Mosquito Population Dynamics: The Case of Culex pipiens in Northwestern Italy. PLoS One 2016; 11:e0154018. [PMID: 27105065 PMCID: PMC4841511 DOI: 10.1371/journal.pone.0154018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 04/07/2016] [Indexed: 11/19/2022] Open
Abstract
Culex pipiens mosquito is a species widely spread across Europe and represents a competent vector for many arboviruses such as West Nile virus (WNV), which has been recently circulating in many European countries, causing hundreds of human cases. In order to identify the main determinants of the high heterogeneity in Cx. pipiens abundance observed in Piedmont region (Northwestern Italy) among different seasons, we developed a density-dependent stochastic model that takes explicitly into account the role played by temperature, which affects both developmental and mortality rates of different life stages. The model was calibrated with a Markov chain Monte Carlo approach exploring the likelihood of recorded capture data gathered in the study area from 2000 to 2011; in this way, we disentangled the role played by different seasonal eco-climatic factors in shaping the vector abundance. Illustrative simulations have been performed to forecast likely changes if temperature or density–dependent inputs would change. Our analysis suggests that inter-seasonal differences in the mosquito dynamics are largely driven by different temporal patterns of temperature and seasonal-specific larval carrying capacities. Specifically, high temperatures during early spring hasten the onset of the breeding season and increase population abundance in that period, while, high temperatures during the summer can decrease population size by increasing adult mortality. Higher densities of adult mosquitoes are associated with higher larval carrying capacities, which are positively correlated with spring precipitations. Finally, an increase in larval carrying capacity is expected to proportionally increase adult mosquito abundance.
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Affiliation(s)
- Giovanni Marini
- Department of Mathematics, University of Trento, Trento, Italy
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige (TN), Italy
- * E-mail:
| | - Piero Poletti
- Bruno Kessler Foundation, Trento, Italy
- Dondena Centre for Research on Social Dynamics and Public Policy, Department of Policy Analysis and Public Management, Universitá Commerciale L. Bocconi, Milan, Italy
| | - Mario Giacobini
- Department of Veterinary Sciences, University of Torino, Torino, Italy
| | - Andrea Pugliese
- Department of Mathematics, University of Trento, Trento, Italy
| | | | - Roberto Rosà
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige (TN), Italy
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16
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Schönenberger AC, Wagner S, Tuten HC, Schaffner F, Torgerson P, Furrer S, Mathis A, Silaghi C. Host preferences in host-seeking and blood-fed mosquitoes in Switzerland. MEDICAL AND VETERINARY ENTOMOLOGY 2016; 30:39-52. [PMID: 26685926 DOI: 10.1111/mve.12155] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Revised: 07/22/2015] [Accepted: 08/31/2015] [Indexed: 06/05/2023]
Abstract
The avian zoonotic agent for West Nile virus (WNV) can cause neuroinvasive disease in horses and humans and is expanding its range in Europe. Analyses of the risk for transmission to these hosts in non-endemic areas are necessary. Host preferences of mosquitoes (Diptera: Culicidae), the main vectors of WNV, were determined in Switzerland using animal-baited trap (horse, chickens) experiments at a natural and a periurban site. This was undertaken on four occasions during May-September 2014. In addition, the hosts of 505 blood-fed mosquitoes collected in a zoo and in the field were determined. Mosquito data obtained in the animal bait experiments were corrected for host weight and body surface area and by Kleiber's scaling factor. Collections of 11-14 different mosquito species were achieved with these approaches. Statistically significant host preferences were identified in three species in both approaches. The other species showed opportunistic feeding behaviours to varying extents. Specifically, the invasive species Hulecoeteomyia japonica (= Aedes japonicus) was identified for the first time as feeding on avians in nature. Abundance data, spatiotemporal activity and laboratory vector competence for WNV suggested that, in addition to the main WNV vector Culex pipiens, H. japonica and Aedimorphus vexans (= Aedes vexans) are the most likely candidate bridge vectors for WNV transmission in Switzerland.
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Affiliation(s)
- A C Schönenberger
- Vector Entomology Unit, National Centre for Vector Entomology, Institute of Parasitology, Faculty of Veterinary Science (Vetsuisse), University of Zurich, Zurich, Switzerland
| | - S Wagner
- Vector Entomology Unit, National Centre for Vector Entomology, Institute of Parasitology, Faculty of Veterinary Science (Vetsuisse), University of Zurich, Zurich, Switzerland
| | - H C Tuten
- Vector Entomology Unit, National Centre for Vector Entomology, Institute of Parasitology, Faculty of Veterinary Science (Vetsuisse), University of Zurich, Zurich, Switzerland
| | - F Schaffner
- Vector Entomology Unit, National Centre for Vector Entomology, Institute of Parasitology, Faculty of Veterinary Science (Vetsuisse), University of Zurich, Zurich, Switzerland
| | - P Torgerson
- Section of Epidemiology, Vetsuisse, University of Zurich, Zurich, Switzerland
| | - S Furrer
- Zürich Zoologischer Garten (Zoo Zürich), Zurich, Switzerland
| | - A Mathis
- Vector Entomology Unit, National Centre for Vector Entomology, Institute of Parasitology, Faculty of Veterinary Science (Vetsuisse), University of Zurich, Zurich, Switzerland
| | - C Silaghi
- Vector Entomology Unit, National Centre for Vector Entomology, Institute of Parasitology, Faculty of Veterinary Science (Vetsuisse), University of Zurich, Zurich, Switzerland
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17
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Fortuna C, Remoli ME, Di Luca M, Severini F, Toma L, Benedetti E, Bucci P, Montarsi F, Minelli G, Boccolini D, Romi R, Ciufolini MG. Experimental studies on comparison of the vector competence of four Italian Culex pipiens populations for West Nile virus. Parasit Vectors 2015; 8:463. [PMID: 26383834 PMCID: PMC4574231 DOI: 10.1186/s13071-015-1067-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/01/2015] [Indexed: 12/25/2022] Open
Abstract
Background West Nile virus (WNV) is a vector-borne disease responsible for causing epidemics in many areas of the world. The virus is maintained in nature by an enzootic bird-mosquito-bird cycle and occasionally transmitted to other hosts, such as equines and humans. Culex species, in particular the ubiquitous species Culex pipiens is thought to play a major vector role both in enzootic and epizootic maintenance and transmission of WNV. Introduced in Europe in recent years, since 2008 WNV has been stably circulating mainly in the Northeastern regions of Italy, although sporadic equine and/or human cases, as well as WNV infected Cx. pipiens pools, have been recorded in other Italian areas. The scope of our study was to evaluate the potential competence of some Italian populations of Cx. pipiens to transmit WNV and to assess their ability for vertical transmission of the virus. For this purpose four Italian populations, from different areas, were experimentally infected. Methods After the infectious blood meal, fed females were monitored for 32 days to determine the length of viral extrinsic incubation period. WNV titre of infected mosquitoes was evaluated both by quantitative Real Time PCR and viral titration by Plaque Forming Units/ml (PFU/mL) in VERO cells. Potential Infection, Dissemination, Transmission rates (IR, DR, TR) were assessed by detection of the virus in body, legs plus wings and saliva of the fed females, respectively. Results All tested populations were susceptible to the WNV infection. The viral presence in legs and wings demonstrated the ability of WNV to disseminate in the mosquitoes. Viral RNA was detected in the saliva of tested populations. No significant differences in TR values were observed among the four studied populations. The offspring of the Cx. pipiens infected females were WNV negative. Conclusions Our study addressed an important issue in the knowledge on the complex WNV-vector relationships in Italy, indicating that all Italian Cx. pipiens populations tested exhibited vector competence for WNV. Further studies should be performed in order to better clarify the role of other factors (vector density, climatic conditions, reservoir presence etc.) in order to predict where and when WNV outbreaks could occur.
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Affiliation(s)
- Claudia Fortuna
- Unit of Viral diseases and attenuated vaccine, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Maria Elena Remoli
- Unit of Viral diseases and attenuated vaccine, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Marco Di Luca
- Unit of Vector-borne Diseases and International Health, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Francesco Severini
- Unit of Vector-borne Diseases and International Health, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Luciano Toma
- Unit of Vector-borne Diseases and International Health, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Eleonora Benedetti
- Unit of Viral diseases and attenuated vaccine, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Paola Bucci
- Unit of Viral diseases and attenuated vaccine, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Fabrizio Montarsi
- Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, PD, Italy.
| | - Giada Minelli
- National Centre for Epidemiology, Surveillance and Health Promotion, Unit of Statistics Istituto Superiore di Sanità, Rome, Italy.
| | - Daniela Boccolini
- Unit of Vector-borne Diseases and International Health, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Roberto Romi
- Unit of Vector-borne Diseases and International Health, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Maria Grazia Ciufolini
- Unit of Viral diseases and attenuated vaccine, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
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18
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Marcantonio M, Rizzoli A, Metz M, Rosà R, Marini G, Chadwick E, Neteler M. Identifying the environmental conditions favouring West Nile Virus outbreaks in Europe. PLoS One 2015; 10:e0121158. [PMID: 25803814 PMCID: PMC4372576 DOI: 10.1371/journal.pone.0121158] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 01/28/2015] [Indexed: 11/29/2022] Open
Abstract
West Nile Virus (WNV) is a globally important mosquito borne virus, with significant implications for human and animal health. The emergence and spread of new lineages, and increased pathogenicity, is the cause of escalating public health concern. Pinpointing the environmental conditions that favour WNV circulation and transmission to humans is challenging, due both to the complexity of its biological cycle, and the under-diagnosis and reporting of epidemiological data. Here, we used remote sensing and GIS to enable collation of multiple types of environmental data over a continental spatial scale, in order to model annual West Nile Fever (WNF) incidence across Europe and neighbouring countries. Multi-model selection and inference were used to gain a consensus from multiple linear mixed models. Climate and landscape were key predictors of WNF outbreaks (specifically, high precipitation in late winter/early spring, high summer temperatures, summer drought, occurrence of irrigated croplands and highly fragmented forests). Identification of the environmental conditions associated with WNF outbreaks is key to enabling public health bodies to properly focus surveillance and mitigation of West Nile virus impact, but more work needs to be done to enable accurate predictions of WNF risk.
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Affiliation(s)
- Matteo Marcantonio
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
- * E-mail:
| | - Annapaola Rizzoli
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Markus Metz
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Roberto Rosà
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Giovanni Marini
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Elizabeth Chadwick
- School of Bioscience, Cardiff University, Cardiff, Wales, United Kingdom
| | - Markus Neteler
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
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19
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Montarsi F, Mazzon L, Cazzin S, Ciocchetta S, Capelli G. Seasonal and Daily Activity Patterns of Mosquito (Diptera: Culicidae) Vectors of Pathogens in Northeastern Italy. JOURNAL OF MEDICAL ENTOMOLOGY 2015; 52:56-62. [PMID: 26336280 DOI: 10.1093/jme/tju002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The seasonal and daily activity of mosquito vectors of pathogens affecting animals and humans were studied in northeastern Italy at a site within the Po River Delta Park. A CDC-CO2 trap and a gravid trap were operated at 2-h intervals for 24 h every 15 d from May to October 2010. Overall, 5,788 mosquitoes comprising six species were collected, namely Culex pipiens L. (75.1% of total), Aedes caspius (Pallas) (15.2%), Aedes vexans (Meigen) (6.9%), Anopheles maculipennis s.l. Meigen (2.6%), Culiseta annulata (Schrank) (0.2%), and Culex modestus Ficalbi (<0.1%). The relative abundance of these species increased from May until the beginning of July and then decreased, disappearing at the beginning of October. The diel host-seeking patterns and oviposition site-seeking patterns were species specific and were differentially affected by the ecological variables recorded at the day and hour of mosquito collection or two weeks before collection. Knowledge of the seasonal and daily host-seeking patterns of mosquitoes highlights the time periods of the day and the seasons of potential exposure for animals and humans to mosquito-borne pathogens, therefore delineating the best time for the application of preventive measures. Furthermore, knowledge of the oviposition site-seeking activity of the mosquitoes optimizes the capture of gravid females, thereby enhancing the likelihood of detecting pathogens.
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Affiliation(s)
- Fabrizio Montarsi
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università, 10, 35020 Legnaro (Padua), Italy. Corresponding author, e-mail:
| | - Luca Mazzon
- Dipartimento di Agronomia Ambientale e Produzioni Vegetali - Entomologia, University of Padua, Viale dell'Università, 16, 35020 Legnaro (Padua), Italy
| | - Stefania Cazzin
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università, 10, 35020 Legnaro (Padua), Italy
| | - Silvia Ciocchetta
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università, 10, 35020 Legnaro (Padua), Italy
| | - Gioia Capelli
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università, 10, 35020 Legnaro (Padua), Italy
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20
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Rosà R, Marini G, Bolzoni L, Neteler M, Metz M, Delucchi L, Chadwick EA, Balbo L, Mosca A, Giacobini M, Bertolotti L, Rizzoli A. Early warning of West Nile virus mosquito vector: climate and land use models successfully explain phenology and abundance of Culex pipiens mosquitoes in north-western Italy. Parasit Vectors 2014; 7:269. [PMID: 24924622 PMCID: PMC4061321 DOI: 10.1186/1756-3305-7-269] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 06/03/2014] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND West Nile Virus (WNV) is an emerging global health threat. Transmission risk is strongly related to the abundance of mosquito vectors, typically Culex pipiens in Europe. Early-warning predictors of mosquito population dynamics would therefore help guide entomological surveillance and thereby facilitate early warnings of transmission risk. METHODS We analysed an 11-year time series (2001 to 2011) of Cx. pipiens mosquito captures from the Piedmont region of north-western Italy to determine the principal drivers of mosquito population dynamics. Linear mixed models were implemented to examine the relationship between Cx. pipiens population dynamics and environmental predictors including temperature, precipitation, Normalized Difference Water Index (NDWI) and the proximity of mosquito traps to urban areas and rice fields. RESULTS Warm temperatures early in the year were associated with an earlier start to the mosquito season and increased season length, and later in the year, with decreased abundance. Early precipitation delayed the start and shortened the length of the mosquito season, but increased total abundance. Conversely, precipitation later in the year was associated with a longer season. Finally, higher NDWI early in the year was associated with an earlier start to the season and increased season length, but was not associated with abundance. Proximity to rice fields predicted higher total abundance when included in some models, but was not a significant predictor of phenology. Proximity to urban areas was not a significant predictor in any of our models. Predicted variations in start of the season and season length ranged from one to three weeks, across the measured range of variables. Predicted mosquito abundance was highly variable, with numbers in excess of 1000 per trap per year when late season temperatures were low (average 21°C) to only 150 when late season temperatures were high (average 30°C). CONCLUSIONS Climate data collected early in the year, in conjunction with local land use, can be used to provide early warning of both the timing and magnitude of mosquito outbreaks. This potentially allows targeted mosquito control measures to be implemented, with implications for prevention and control of West Nile Virus and other mosquito borne diseases.
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Affiliation(s)
- Roberto Rosà
- Dipartimento di Biodiversità ed Ecologia Molecolare, Centro Ricerca e Innovazione, Fondazione Edmund Mach, San Michele all'Adige, TN, Italia.
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Retrospective space-time analysis methods to support West Nile virus surveillance activities. Epidemiol Infect 2014; 143:202-13. [PMID: 24641869 DOI: 10.1017/s0950268814000442] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The steep increase in human West Nile virus (WNV) infections in 2011-2012 in north-eastern Italy prompted a refinement of the surveillance plan. Data from the 2010-2012 surveillance activities on mosquitoes, equines, and humans were analysed through Bernoulli space-time scan statistics, to detect the presence of recurrent WNV infection hotspots. Linear models were fit to detect the possible relationships between WNV occurrence in humans and its activity in mosquitoes. Clusters were detected for all of the hosts, defining a limited area on which to focus surveillance and promptly identify WNV reactivation. Positive relationships were identified between WNV in humans and in mosquitoes; although it was not possible to define precise spatial and temporal scales at which entomological surveillance could predict the increasing risk of human infections. This stresses the necessity to improve entomological surveillance by increasing both the density of trapping sites and the frequency of captures.
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