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Human and animal vector-borne diseases, particularly mosquito-borne diseases, are emerging or re-emerging worldwide. Six Aedes invasive mosquito (AIM) species were introduced to Europe since the 1970s: Aedes aegypti, Ae. albopictus, Ae. japonicus, Ae. koreicus, Ae. atropalpus and Ae. triseriatus. Here, we report the results of AIMSurv2020, the first pan-European surveillance effort for AIMs. Implemented by 42 volunteer teams from 24 countries. And presented in the form of a dataset named “AIMSurv Aedes Invasive Mosquito species harmonized surveillance in Europe. AIM-COST Action. Project ID: CA17108”. AIMSurv2020 harmonizes field surveillance methodologies for sampling different AIMs life stages, frequency and minimum length of sampling period, and data reporting. Data include minimum requirements for sample types and recommended requirements for those teams with more resources. Data are published as a Darwin Core archive in the Global Biodiversity Information Facility- Spain, comprising a core file with 19,130 records (EventID) and an occurrences file with 19,743 records (OccurrenceID). AIM species recorded in AIMSurv2020 were Ae. albopictus, Ae. japonicus and Ae. koreicus, as well as native mosquito species. This study was funded by the Autonomous Province of Trento (Italy) under the project ‘Coordinated surveillance actions on invasive alien species and emerging vector borne diseases’; the City Health Office of the City of Zagreb, within the ‘Program for monitoring invasive mosquito species in the area of the City of Zagreb in 2020’; the Consejería de Economía e Infraestructura of the Junta de Extremadura and the European Regional Development Fund, a Way to Make Europe, through the research project IB16135; Dirección de Salud Pública (Gobierno Vasco), Project EU-LIFE 18 IPC/ES/000001 (Urban Klima 2050) y Programa Estatal de Vigilancia de mosquitos en puertos y Aeropuertos, del Ministerio de Sanidad (Gobierno de España); EMME-CARE project, which has been funded from the European Union’s Horizon 2020 Research and Innovation Programme (grant agreement ID 856612); Institute of Zoology under the project EVOLANTER (project no. 20.80009.7007.02). RL is funded by the Federal Ministry of Education and Research of Germany (BMBF) under the project NEED (grant no. 01Kl2022); LIFE CONOPS project (LIFE12 ENV/GR/000466), funded by the European Commission in the framework of the program LIFE + Environment Policy and Governance; Municipalities of Slovenia: City Municipality of Nova Gorica, City Municipality of Koper, Municipality of Izola, Municipality of Piran and Municipality of Ankaran; National Research, Development and Innovation Office (NKFIH grant numbers KH-130379, PD-135143, FK-138563 and K-135841). The research activity of KK was supported by the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences and by the ÚNKP-20-5-PTE-597 New National Excellence Program of the Ministry for Innovation and Technology; Portuguese National Program for Vector Surveillance (REVIVE) and we are particularly grateful to the regional workgroup of Algarve for the monitoring activities; PR (19_ECO_0070) project ‘Aves y Enfermedades Infecciosas Emergentes: Impacto de las Especies Exóticas y Migratorias en la transmisión de Malaria aviar y el virus del Nilo Occidental – AvEIEs’ from ‘Ayudas Fundación BBVA a Equipos de Investigación Científica 2019’; project grant number 57 PCCDI/2018, grant agency ‘The Executive Unit for Financing Higher Education, Research, Development and Innovation’ (UEFISCDI) Romania, ‘Collegium Talentum Programme’ of Hungary, Eötvös Loránd University’s ‘Homeland higher education study grant’; Slovak Research Agency VEGA nr. 2/0140/21; Vector Control Needs Assessment in Cyprus, contracted by the World Health Organization (reference 2020/1040069-0); Veneto and Friuli Venezia Giulia Regions (Regional Prevention Plans ‘Entomological Surveillance of vector-borne diseases’ in the Veneto and Friuli Venezia Giulia Regions); the Institute of Public Health, Albania under the program of mosquitoes control in urban and coastal areas.

Additional file 3: Figures S1–S19. Individual layers (ecological risk factors) that were used for constructing the hazard maps.

Additional file 4: Figures S20–S25. Schematic representation of the steps taken to construct the hazard maps for the establishment of each of the six arboviruses.

Additional file 1: Figure S1. Presence records and species distribution map obtained with Aedes albopictus Maxent model. Figure S2. Relationship between nineteen European bioclimatic variables (http://www.worldclim.com) for occurrence records buffers of 200 km of radius with histogram and Kernel density (diagonal), Pearson’s correlation coefficient (r) and its significance (above the diagonal) and scatterplot and linear regression (below the diagonal). *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001. Figure S3. Cluster with nineteen European bioclimatic variables (http://www.worldclim.com) for occurrence records buffers of 200 km of radius. Figure S4. Map with eleven presence records of Aedes albopictus in the Netherlands. The sites are Almere, Assen, Emmeloord, Etten-Leur, Hardenberg, Lelystad, Moerdijk, Montfoort, Oosterhout, Oss, Weert. Map by authors. Figure S5. Maps showing maximum, median, minimum and standard deviation of habitat suitability obtained with Aedes albopictus Maxent model. Figure S6. The relative contribution of five environment variables (BIO11, BIO8, BIO7, BIO2, BIO12) to the model according to the regularized training gain of jackknife test in the Aedes albopictus Maxent model. Blue bars show the influence of each variable alone and green bars show the performance of the model when the variable is removed from the model. Figure S7. Response curves showing the relationships between the probability of presence of Aedes albopictus and five environment variables (BIO11, BIO8, BIO7, BIO2, BIO12). Figure S8. A scatter plot and the corresponding regression line and regression equation for the relationship between the dependent variable air temperature TG (°C × 0.1) and the independent variable LST (°C × 0.01). Abbreviations: r, Pearson’s correlation coefficient; R-square linear, coefficient of determination; P, P-value.

Additional file 2: Text S1. Description of the methods used for modelling mosquito abundance, including information on mosquito data collection, the environmental data used and the statistical methods applied.

The availability of data on distribution and density of mosquito vectors of disease is needed to understand the risk of mosquito-borne diseases. In case of an outbreak of a newly introduced mosquito-borne pathogen of medical or veterinary importance, such information is required in order to decide on a contingency and eventual control plan. In the recent decade, several exotic mosquito species have become established in European countries and they have rapidly expanded their distribution. The rationale for the present study was the increasingly frequent reporting of invasive mosquito species (IMS) in the Netherlands, some of which are known vectors of infectious diseases, as well as the lack of detailed knowledge on the spatio-temporal distribution of the indigenous mosquito fauna. The aim was therefore to develop methodologies for acquiring accurate information on the actual and potential distribution of indigenous and exotic mosquito species in the Netherlands, and to evaluate the surveillance and control methodologies applied after IMS findings. To establish a baseline for the spatio-temporal distribution of the indigenous mosquito fauna present in the Netherlands, a survey was conducted at the start of the study. Cross-sectional mosquito field surveys were carried out over a period of four years (2010-2013). These surveys provided occurrence maps for 26 indigenous species. One invasive mosquito species, Aedes japonicus, was discovered using this strategy. Furthermore, data on seasonality of the species, biodiversity and habitat preferences were also provided. Using the collected data on occurrence and abundance, a special study using random forest models was done to investigate the potential spatial distribution and population density of Anopheles plumbeus, a native nuisance mosquito species. I found a high environmental suitability and abundance of this species in the south-eastern provinces, mostly associated with abandoned pig farm buildings, and reports of biting nuisance. The identification of pathways for introduction of IMS was investigated in a next step taking into account the current knowledge and expert opinion. This was done in order to decide on the surveillance strategies needed to reduce the risk of future IMS introductions and/or potential outbreaks of mosquito-borne diseases. Four main routes for IMS introduction and dispersal were identified: the trade in used tires, the import of Lucky bamboo plants from Asia, the passive transport of IMS in vehicles (traffic by road, airplanes, and sea), and the natural dispersal of IMS. The results of the risk-based surveillance of IMS revealed yearly introductions of Ae. albopictus since 2010 at used tire companies and Lucky bamboo greenhouses, sporadic findings of Ae. japonicus associated with used tire trade, the first aircraft associated import of Ae. aegypti in Europe, and the first associated Ae. japonicus import with Lucky bamboo plants from elsewhere in the world. The control of these IMS, implemented after detection, has proven effective to avoid proliferation at these locations and their surroundings. Due to the yearly findings of Ae. albopictus, the potential risk of establishment of this invasive species was further investigated using habitat suitability models. Results show that the current average climatic conditions limit the overwintering of eggs of Ae. albopictus and their survival as adults in many inland areas of the country. However, due to the expected increase of the temperatures in the next decades as a result of climate change, these parts of the Netherlands will offer climatic conditions suitable for sustain populations of this species. The results presented in this thesis show that nationwide surveillance of mosquitoes is pivotal to gain detailed information on the spatio-temporal distribution and abundance of mosquito species, which is useful to study the habitat suitability of vector species. Furthermore, this thesis highlights the main pathways for introduction and dispersal of IMS, designed a risk-based surveillance of IMS, and evaluated the surveillance and control measures applied in the Netherlands against IMS introductions. The work presented provides essential insights for identifying locations at risk of vector-borne disease transmission, and for designing targeted control of newly introduced IMS in the Netherlands, which is expected in the future.

Landscape genetics is an approach for understanding how geographical and environ-mental features structure genetic variation. Whether landscape patterns, in particular those created by human land uses, influence gene flow and its intensity to understand the spread of vector-borne diseases. Culicoides dispersal capacities are described as 'dis-persive stratified' which results from the combination of processes occurring at a short distance combined with jumps over long distances. Although winds and local air move-ments have an undeniable role in the dispersal of Culicoides, anthropogenic factors also play a predominant role, particularly at the local level (host distribution, landscape patterns). Our overall objective is to characterize the dispersal abilities of two main vector species in Europe, C. obsoletus and C. chiopterus, showing different host-vector behaviors. However, Culicoides obsoletus is reported in sympatry with one morpholog-ically indistinguishable species, C. scoticus, and other morphologically related species, C. chiopterus, C. dewulfi and C. montanus. Moreover, recently, several authors have report-ed the existence of cryptic diversity within the species commonly called C. obsoletus. Se-quencing a portion of the Cox1 mitochondrial gene of 3,200 C. obsoletus/C. scoticus individ-uals from 17 European countries revealed two clades within C. scoticus and confirmed the presence of at least three undescribed phylogenetic clades (C. obsoletus clade O2, C. obso-letus clade Dark and one not yet named) close to C. obsoletus. These results are reinforced by rDNA16S mitochondrial gene sequences and a gene coding for ribosomal rDNA18S, over the entire haplotypic diversity resulting from Cox1 barcoding. Then, we investigated how dispersion shapes the spatial arrangement of C. obsoletus genetic diversity in Europe using 13 microsatellite markers by observing patterns of allelic frequency distributions. This work is the first step to a more comprehensive study on the landscape genetics of two main vector species in the Palearctic region, C. obsoletus and C. chiopterus.

Background: Models for the spatial distribution of vector species are important tools in the assessment of the risk of establishment and subsequent spread of vector-borne diseases. The aims of this study are to define the environmental conditions suitable for several mosquito species through species distribution modelling techniques, and to compare the results produced with the different techniques.Methods: Three different modelling techniques, i.e., non-linear discriminant analysis, random forest and generalised linear model, were used to investigate the environmental suitability in the Netherlands for three indigenous mosquito species (Culiseta annulata, Anopheles claviger and Ochlerotatus punctor). Results obtained with the three statistical models were compared with regard to: (i) environmental suitability maps, (ii) environmental variables associated with occurrence, (iii) model evaluation.Results: The models indicated that precipitation, temperature and population density were associated with the occurrence of Cs. annulata and An. claviger, whereas land surface temperature and vegetation indices were associated with the presence of Oc. punctor. The maps produced with the three different modelling techniques showed consistent spatial patterns for each species, but differences in the ranges of the predictions. Non-linear discriminant analysis had lower predictions than other methods. The model with the best classification skills for all the species was the random forest model, with specificity values ranging from 0.89 to 0.91, and sensitivity values ranging from 0.64 to 0.95.Conclusions: We mapped the environmental suitability for three mosquito species with three different modelling techniques. For each species, the maps showed consistent spatial patterns, but the level of predicted environmental suitability differed; NLDA gave lower predicted probabilities of presence than the other two methods. The variables selected as important in the models were in agreement with the existing knowledge about these species. All model predictions had a satisfactory to excellent accuracy; best accuracy was obtained with random forest. The insights obtained can be used to gain more knowledge on vector and non-vector mosquito species. The output of this type of distribution modelling methods can, for example, be used as input for epidemiological models of vector-borne diseases.

International audience; In the past decade, two pathogens transmitted by Culicoides biting midges (Diptera: Ceratopogonidae), bluetongue virus and Schmallenberg virus, have caused serious economic losses to the European livestock industry, most notably affecting sheep and cattle. These outbreaks of arboviral disease have highlighted large knowledge gaps on the biology and ecology of indigenous Culicoides species. With these research gaps in mind, and as a means of assessing what potential disease outbreaks to expect in the future, an international workshop was held in May 2013 at Wageningen University, The Netherlands. It brought together research groups from Belgium, France, Germany, Spain, Switzerland, United Kingdom and The Netherlands, with diverse backgrounds in vector ecology, epidemiology, entomology, virology, animal health, modelling, and genetics. Here, we report on the key findings of this workshop.