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The continuous expansion of Aedes albopictus in Europe and the increases in autochthonous arboviruses transmissions in the region urge a better understanding of the virus transmission dynamic. Recent work described enhanced chikungunya virus (CHIKV) dissemination in Aedes aegypti mosquitoes exposed to a virus-free blood meal three days after their infection with CHIKV. Our study investigated the impact of a second blood meal on the vector competence of Ae. albopictus from southern Switzerland infected with CHIKV. Seven-day-old Ae. albopictus females were exposed to CHIKV-spiked blood and incubated at constant (27 °C) and fluctuating (14–28 °C) temperatures. Four days post-infection (dpi), some of these females were re-fed with a non-infectious blood meal. Virus infectivity, dissemination, transmission rate, and efficiency were investigated at seven and ten dpi. No enhanced dissemination rate was observed among females fed a second time; however, re-fed females have shown higher transmission efficiency than those fed only once after seven days post-infection and incubated under a fluctuating temperature regime. Vector competence for CHIKV was confirmed in Ae. albopictus from southern Switzerland. We did not observe an increase in dissemination rates among mosquitoes fed a second time (second blood meal), regardless of the temperature regime.

The continuous expansion of invasive Asian tiger mosquito, Aedes albopictus, combined to its ability to transmit arboviruses (e.g. dengue, chikungunya) is raising major public health concern in Europe. In Switzerland, the mosquito is firmly established in most urban areas of the Canton of Ticino, south of the Alps, and there is a real risk that it will colonize also urban areas north of the Alps in the next years. The spatial distribution and colonization of new areas by Ae. albopictus depends on several environmental parameters, such as winter and summer temperatures, and precipitation patterns. A key factor for Ae. albopictus to establish at higher latitudes is the capability to develop cold-tolerant overwintering diapausing eggs under specific environmental conditions. Weather-driven abundance models are used to map the areas of potential distribution and to predict temporal dynamics of Ae. albopictus and the transmission potential of arboviruses. This contribution presents the designed system that integrates low-cost and on-line IoT sensors to monitor temperature, humidity and light with istSOS an OGC Sensor Observation Service server implementation with a user friendly interface and rich feature collection to easily manage this sensor network and distribute data in a standard way (www.istsos.org).

In Switzerland,A regularized logistic regression was used to link the long-term dataset ofThe model performed well, with an AUC of 0.86. Ten socio-environmental predictors were selected as informative, including the road-based distance in minutes of travel by car from the nearest cell established in the previous year. The risk maps showed high suitability forThe areas identified as suitable for

Background The exotic invasive tiger mosquito, Aedes albopictus, appeared in southern Switzerland in 2003. The spread of the mosquito has been surveyed constantly since then, and an integrated vector management (IVM) has been implemented to control its numbers. The control measures focus on the aquatic phase of the mosquito with removal of breeding sites and applications of larvicides in public areas whereas private areas are reached through extensive public information campaigns. Here, we evaluated the efficacy of the IVM. Methods Since all the municipalities with Ae. albopictus in southern Switzerland are currently implementing the IVM, Italian municipalities just across the Swiss-Italian border, where Ae. albopictus is present but no coordinated intervention programme is in place, served as control. Ovitraps and adult female traps were used to measure mosquito abundance in 2019. Generalised mixed-effects models were used to model the numbers of Ae. albopictus eggs and adult females collected. These numbers of Ae. albopictus eggs were compared to the numbers of eggs collected in 2012 and 2013 in a previous assessment of the IVM, using a hurdle model. Results Mean numbers of Ae. albopictus eggs and adult females in 2019 were consistently higher in the municipalities not following an IVM programme. In these municipalities, there were about four times (3.8) more eggs than in the municipalities implementing an IVM programme. Also, the numbers of eggs and adult females increased steadily from the beginning of the Ae. albopictus reproductive season, reaching a peak in August. In contrast, the increase in numbers of Ae. albopictus was much more contained in the municipalities implementing an IVM programme, without reaching an evident peak. Comparison with data from 2012 and 2013 indicates that the gap between intervention and non-intervention areas may have almost doubled in the past 6 years. Conclusions The results of the survey strongly support the efficacy of the IVM programme implemented in southern Switzerland compared to municipalities without defined control measures. With the constant implementation of an IVM, it appears possible to contain the numbers of Ae. albopictus at a manageable level, reducing the nuisance for the human population and the risk of arbovirus epidemics. Graphical Abstract

Epidemics of mosquito-borne diseases such as chikungunya and dengue fever are becoming more frequent around the world. In Switzerland, autochthonous cases have not been reported so far, although the presence of the vector Aedes albopictus in urban areas of southern Switzerland increases the risk of indigenous transmissions subsequent to imported cases. In 2018, the potential risk of an outbreak of arboviral diseases was assessed in five municipalities of southern Switzerland. The population abundance of Ae. albopictus was evaluated during the mosquito active season by the mean number of Ae. albopictus bites per day per person (estimated using the human landing collection method) and the risk of outbreak in the case of the introduction of chikungunya, dengue or Zika viruses was estimated. In the five localities investigated, no epidemic risk appeared to be present for any of the arboviruses taken into consideration in the initial months (i.e. mid-May to end of July) of Ae. albopictus activity. In the case of the introduction of chikungunya (mutated or not), dengue (serotype 1) or Zika (African lineage) viruses during mid-end August, an epidemic could have occurred in all the municipalities investigated. In mid-end September, the introduction of same arboviruses could have led to an epidemic in three of the five municipalities investigated.

We report here the full-length genome sequence of a rhabdovirus strain detected in a pool of 21 Culex pipiens and Culex torrentium mosquitos collected in southern Switzerland. The genome has a length of 11,914 nucleotides and encodes five major putative open reading frames.

We report here the full-length genome sequence of a rhabdovirus strain detected in a pool of 21 Culex pipiens and Culex torrentium mosquitos collected in southern Switzerland. The genome has a length of 11,914 nucleotides and encodes five major putative open reading frames.

Background The Preparedness Plan for Surveillance and Interventions on Emerging Vector-Borne Diseases (VBDs) in Southern Switzerland outlines the strategy for preventing and managing potential outbreaks, as well as the surveillance and control activities with a specific focus on Aedes-borne diseases transmitted by Aedes albopictus mosquitoes. The objective of the plan is to provide Public Health Authorities with a framework of preventive and control measures according to the situation and level of epidemic risks. Material and methods The plan is divided into various phases representing the different steps for all potential situations, ranging from no vectors and no transmission risk to epidemic levels with multiple autochthonous/local cases of hospitalization (and deaths) until the end of the epidemic. An algorithm presents how decisions are taken to move from one phase of the plan to another, with detailed activities for different partners and strategies for each specific phase. Results The different phases of the plan include activities on disease surveillance and clinical case management, on vector surveillance and control, communication and coordination of activities. The plan is divided into five phases of activities and decision levels. From phase 0 (no cases) to phase 1 (low number of local cases, less than 5), phase 2 (small outbreak with more than 5 local cases), phase 3 (epidemic) and phase 4 (return to no more cases). Conclusion The plan has been approved by the cantonal authorities and will be submitted to federal authorities. The required implementation tests will begin shortly.

Aedes albopictus, also known as the “Asian Tiger Mosquito”, is an invasive mosquito species to Europe causing high concern in public health due to its severe nuisance and its vectorial capacity for pathogens such as dengue, chikungunya, yellow fever and Zika. Consequently, the responsible authorities implement management activities to reduce its population density, possibly to below noxious and epidemiological thresholds. In urban areas, these aims are difficult to achieve because of the species’ ability to develop in a wide range of artificial breeding sites, mainly private properties. This document (Management Plan) has been structured to serve as a comprehensive practical and technical guide for stakeholders in organizing the vector control activities in the best possible way. The current plan includes coordinated actions such as standardized control measures and quality control activities, monitoring protocols, activities for stakeholders and local communities, and an emergency vector control plan to reduce the risk of an epidemic.

Background Aedes aegypti and Ae. albopictus are two highly invasive mosquito species, both vectors of several viruses, including dengue, chikungunya and Zika. While Ae. aegypti is the primary vector in the tropics and sub-tropics, Ae. albopictus is increasingly under the public health watch as it has been implicated in arbovirus-transmission in more temperate regions, including continental Europe. Vector control using insecticides is the pillar of most control programmes; hence development of insecticide resistance is of great concern. As part of a Brazilian-Swiss Joint Research Programme we set out to assess whether there are any signs of existing or incipient insecticide resistance primarily against the larvicide Bacillus thuringiensis svar. israelensis (Bti), but also against currently applied and potentially alternative insecticides in our areas, Recife (Brazil) and the Swiss-Italian border region. Methods Following World Health Organization guidelines, dose-response curves for a range of insecticides were established for both colonized and field caught Ae. aegypti and Ae. albopictus. The larvicides included Bti, two of its toxins, Cry11Aa and Cry4Ba, Lysinibacillus sphaericus, Vectomax CG®, a formulated combination of Bti and L. sphaericus, and diflubenzuron. In addition to the larvicides, the Swiss-Italian Ae. albopictus populations were also tested against five adulticides (bendiocarb, dichlorodiphenyltrichloroethane, malathion, permethrin and λ-cyhalothrin). Results Showing a similar dose-response, all mosquito populations were fully susceptible to the larvicides tested and, in particular, to Bti which is currently used both in Brazil and Switzerland. In addition, there were no signs of incipient resistance against Bti as larvae were equally susceptible to the individual toxins, Cry11Aa and Cry4Ba. The field-caught Swiss-Italian populations were susceptible to the adulticides tested but DDT mortality rates showed signs of reduced susceptibility. Conclusions The insecticides currently used for mosquito control in Switzerland and Brazil are still effective against the target populations. The present study provides an important reference as relatively few insecticide susceptibility surveys have been carried out with Ae. albopictus. Electronic supplementary material The online version of this article doi:(10.1186/s13071-017-2364-5) contains supplementary material, which is available to authorized users.

Invasive species can encounter environments different from their source populations, which may trigger rapid adaptive changes after introduction (niche shift hypothesis). To test this hypothesis, we investigated whether postintroduction evolution is correlated with contrasting environmental conditions between the European invasive and source ranges in the Asian tiger mosquito Aedes albopictus. The comparison of environmental niches occupied in European and source population ranges revealed more than 96% overlap between invasive and source niches, supporting niche conservatism. However, we found evidence for postintroduction genetic evolution by reanalyzing a published ddRADseq genomic dataset from 90 European invasive populations using genotype–environment association (GEA) methods and generalized dissimilarity modeling (GDM). Three loci, among which a putative heat‐shock protein, exhibited significant allelic turnover along the gradient of winter precipitation that could be associated with ongoing range expansion. Wing morphometric traits weakly correlated with environmental gradients within Europe, but wing size differed between invasive and source populations located in different climatic areas. Niche similarities between source and invasive ranges might have facilitated the establishment of populations. Nonetheless, we found evidence for environmental‐induced adaptive changes after introduction. The ability to rapidly evolve observed in invasive populations (genetic shift) together with a large proportion of unfilled potential suitable areas (80%) pave the way to further spread of Ae. albopictus in Europe., Invasive species can encounter environments different from their source populations, which may trigger rapid adaptive changes after introduction. Combining niche distribution modeling, genotype–environment associations and generalized dissimilarity modeling, we found evidence for environmental‐induced adaptive changes in the Asian tiger mosquito Aedes albopictus after its introduction in Europe. The ability to rapidly evolve observed in invasive populations together with a large proportion of unfilled potential suitable areas pave the way to further spread of Ae. albopictus in Europe.

A metagenomic study was performed on 498 female and 40 male Aedes albopictus mosquitos collected in August and September 2019 in Ticino, a region in southern Switzerland, to address the question regarding the risk of the local transmission of zoonotic viruses. A total of 13 viruses from seven different virus families and several unclassified viral taxa were identified. Reads of insect-specific flaviviruses were present in all pools, and a complete genome of aedes flavivirus was assembled and phylogenetically analysed. The most abundant virus was Wenzhou sobemo-like virus, assembled from 1.3 &times, 105 to 3.6 &times, 106 reads in each pool. In a pool of male mosquitos, a complete genome of aedes Iflavi-like virus was detected and phylogenetically analysed. Most importantly, genomes of human pathogenic viruses were not found. This is the first study to determine the virome of Ae. albopictus from Switzerland and forms a baseline for future longitudinal investigations concerning the potential role of Ae. albopictus as a vector of clinically relevant viruses.

According to predictions bases on a climate-driven large-scale model the areas surrounding Lake Léman and, to some extent, the Swiss Plateau are suitable for the spread of Ae. albopictus North of the Alps, while other areas in Switzerland (e.g., the city of Zürich) seem currently too cold in winter for the survival of eggs. However, this model does not take into account particular micro-climate conditions in urban areas where the specie thrives. Climate conditions in urban micro-habitats (in particular catch basins) increase the probability of the survival of diapausing eggs in the winter season favoring the colonization of new cities that were thought to be too cold for the survival of the eggs. Therefore, there is an urgent need for appropriate monitoring tools and risk-based surveillance of Ae. albopictus populations. In 2018 a multidisciplinary group of researchers from the University of Applied Sciences and Arts of Southern Switzerland (SUPSI) has joined launching the project ALBIS (Albopictus Integrated System). The designed system focuses on the monitoring of urban catch basins, primarily on micro-climate environmental sensing, data transmission, data acquisition and data dissemination. The gathered data are the input for an empirical machine learning model for the prediction of spatial and temporal distribution of the Ae. albopictus. The first real time monitoring tests are in progress in the pilot area in the city of Lugano in the Canton Ticino. Fully functional prototypes have been engineered by the Institute of Earth Science in collaboration with a local electronics manufacturer (TECinvent) combined with the Open Source istSOS OGC Sensor Observation Service software for data acquisition and dissemination, and in the first tests cases have demonstrated good quality in terms of energy efficiency, data quality and data transmission reliability. The first results demonstrated that temperature in catch basins can be different from outside temperature that is detected by traditional terrain measures: in February 2018 during a period of cold air temperature in Canton Ticino of down to -8°C, the prototype sensor monitoring the catch basins' wall surface shows temperatures up to 6°C higher. Considering that one of the Ae. albopictus establishment thresholds is to have a mean January temperature of >0°C to allow egg overwintering, taking into account this micro-climate environments could lead to more realistic predictions.

Background In Switzerland, the invasive Asian tiger mosquito, Aedes albopictus, is firmly established in the Canton of Ticino, south of the Alps. According to a large-scale distribution model developed in 2013, suitable climatic conditions for the establishment of Ae. albopictus north of the Alps are found in Basel and Geneva while Zurich appears to be characterized by winters currently being too cold for survival of diapausing eggs. However, the spatial resolution of large-scale distribution models might not be sufficient to detect particular climatic conditions existing in urban settings, such as the presence of microclimatic temperatures, which may positively influence the probability of diapausing eggs to overwinter. In order to investigate this, microclimatic monitoring of potential diapausing sites (i.e. catch basins) and external controls was performed in January 2017 in Ticino and within the cities of Basel, Geneva and Zurich. Results Mean January temperatures in catch basins of Basel, Geneva and Zurich were always higher than the -1 °C temperature threshold previously set for survival probability of diapausing eggs, while mean January temperatures were below -1 °C in several catch basins south of the Alps, where Ae. albopictus eggs currently overwinter. The catch basin absolute January daily minimum temperatures both south and north of the Alps were in general higher than the external control temperatures. Absolute January daily minimum temperatures in catch basins in Basel, Geneva and Zurich were always above -10 °C, indicating that diapausing Ae. albopictus eggs could potentially survive winter nights in urban areas north of the Alps. Conclusions The findings confirmed previous conclusions that urban catch basins can provide favourable conditions for overwintering of diapausing eggs compared to more cold-exposed sites. The results confirmed the presence of suitable winter conditions for the establishment of Ae. albopictus in the cities of Basel and Geneva. In addition, the microclimate-scale analysis added new information compared to the previous large-scale prevision model by showing that also the city of Zurich could provide winter conditions suitable for the establishment of Ae. albopictus. This illustrates the importance of the resolution of climate data in using models to predict Ae. albopictus distribution., Parasites & Vectors, 11 (1), ISSN:1756-3305

Background The Asian tiger mosquito, Aedes albopictus, is a highly invasive mosquito species of public health importance. In the wake of its arrival in neighbouring Italy the authorities of the canton of Ticino in southern Switzerland initiated a surveillance programme in 2000 that is still on-going. Here we explored the unique data set, compiled from 2003 to 2014, to analyse the local dynamic of introduction and establishment of Ae. albopictus, its relative density in relation to precipitation and temperature, and its potential distribution at the passage from southern to northern Europe. Methods The presence of Ae. albopictus was recorded by ovitraps placed across Ticino. In addition to presence-absence, the relationship between relative egg densities and year, month, temperature and precipitation was analysed by a generalised linear mixed model. Results Since its first detection in 2003 at Ticino’s border with Italy Ae. albopictus has continuously spread north across the lower valleys, mainly along the trans-European motorway, E35. Detailed local analysis showed that industrial areas were colonised by the mosquito before residential areas and that, afterwards, the mosquito was more present in residential than in industrial areas. Ae. albopictus appeared sporadically and then became more present in the same places the following years, suggesting gradual establishment of locally reproducing populations that manage to overwinter. This trend continues as witnessed by both a growing area being infested and increasing egg counts in the ovitraps. There was a clear South-North gradient with more traps being repeatedly positive in the South and fewer eggs laid during periods of intensive precipitation. In the North, the mosquito appeared repeatedly through the years, but never managed to establish, probably because of unfavourable weather conditions and low road traffic. Conclusions Given the present results we assume that additional areas may still become infested. While the current study provides good estimates of relative egg densities and shows the local and regional dynamics of Ae. albopictus invasion, additional parameters ought to be measured to make an objective risk assessment for epidemic disease transmission. The likelihood of Ae. albopictus to further spread and increase in densities calls for continued surveillance. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1577-3) contains supplementary material, which is available to authorized users.

Chikungunya (CHIK) is an emerging or reemerging arboviral infectious disease transmitted to humans by the Asian tiger mosquito, Aedes albopictus (Skuse), and the yellow fever mosquito, Ae. aegypti (L.), particularly in Africa, India, Southeast Asia, and other parts of Europe where numerous outbreaks and epidemics were documented during recent decades. This viral disease is a potential threat to human health worldwide; thus, a quantitative one-step, real-time RT-PCR protocol was developed and assessed as a suitable assay for minimum detection of chikungunya virus (CHIKV) E1 (genus Alphavirus, family Togaviridae) in human serum (7.51 fg/μl) by using the QuantiTect® Probe RT-PCR kit with appropriate synthetic primer (CHIK E1 F and CHIK E1 R) and dual-labeled CHIK E1 probe. Unfortunately, we did not detect any CHIKV from 9 species, namely Ae. albopictus, Aedes (=Ochlerotatus) cantans (Meigen), Ae. cinereus Meigen, Ae. geminus Peus, Ae. vexans (Meigen), Anopheles claviger Meigen, An. maculipennis Meigen s.l., ...

Background In 2012 and 2013, an entomological survey of Aedes albopictus, the Asian tiger mosquito, was carried out in the border region of southern Switzerland and northern Italy, using ovitraps. In July 2013, besides A. albopictus already known to the region several unusual eggs were recovered. Findings A total of 548 seemingly different eggs were found within three communities: Chiasso (Switzerland), and Como and Brunate (Italy). Proteomic diagnostics based on matrix-assisted laser desorption/ionization mass-spectrometry (MALDI-TOF MS) and morphological identification of one reared adult revealed the presence of at least 18 A. (Finlaya) koreicus (Edwards, 1917) specimens. A. koreicus is a species native to Southeast Asia and is competent to transmit Japanese encephalitis and potentially other arboviruses, as well as the dog heartworm Dirofilaria immitis. While new to Switzerland, this invasive species has previously been reported from Belgium, north-eastern Italy and European Russia. Conclusions This is the first report of the introduction of this exotic mosquito species into Switzerland and Lombardy, Italy, suggesting the range of A. koreicus is expanding in Central Europe. As A. koreicus is competent to vector pathogens its establishment imposes a risk to public and veterinary health. From a technical point of view, the presence of A. koreicus alongside A. albopictus requires careful analysis and reliable diagnostics. As a diagnostic tool the use of the recently developed MALDI-TOF MS approach has proofed to be a very useful approach, particularly since hatching rates of A. koreicus seem to be low, making identification by classic morphology difficult, if not impossible.

A wide range of arthropod-borne viruses threaten both human and animal health either through their presence in Europe or through risk of introduction. Prominent among these is West Nile virus (WNV), primarily an avian virus, which has caused multiple outbreaks associated with human and equine mortality. Endemic outbreaks of West Nile fever have been reported in Italy, Greece, France, Romania, Hungary, Russia and Spain, with further spread expected. Most outbreaks in Western Europe have been due to infection with WNV Lineage 1. In Eastern Europe WNV Lineage 2 has been responsible for human and bird mortality, particularly in Greece, which has experienced extensive outbreaks over three consecutive years. Italy has experienced co-circulation with both virus lineages. The ability to manage this threat in a cost-effective way is dependent on early detection. Targeted surveillance for pathogens within mosquito populations offers the ability to detect viruses prior to their emergence in livestock, equine species or human populations. In addition, it can establish a baseline of mosquito-borne virus activity and allow monitoring of change to this over time. Early detection offers the opportunity to raise disease awareness, initiate vector control and preventative vaccination, now available for horses, and encourage personal protection against mosquito bites. This would have major benefits through financial savings and reduction in equid morbidity/mortality. However, effective surveillance that predicts virus outbreaks is challenged by a range of factors including limited resources, variation in mosquito capture rates (too few or too many), difficulties in mosquito identification, often reliant on specialist entomologists, and the sensitive, rapid detection of viruses in mosquito pools. Surveillance for WNV and other arboviruses within mosquito populations varies between European countries in the extent and focus of the surveillance. This study reviews the current status of WNV in mosquito populations across Europe and how this is informing our understanding of virus epidemiology. Key findings such as detection of virus, presence of vector species and invasive mosquito species are summarized, and some of the difficulties encountered when applying a cost-effective surveillance programme are highlighted., Data from Italy were provided by the National and Regional Surveillance Programs supported by the Ministry of Health and the Regional authorities of Veneto, Fruili Venezia Giulia, Emilia and Lombardia. IPZ highly acknowledges the financial contribution of the Swiss Federal Veterinary Office (grant 1.12.17 and National Centre for Vector Ecology). Acknowledgements to the Federal Office for the Environment for financing the mosquito collection activity and the Federal Office for Civil Protection for financing the molecular analysis. Surveillance in Greece was funded by contributions from the Hellenic Centre for Disease Control and Prevention and the Development Agency of Thessaloniki S.A. Spanish surveillance for West Nile virus and mosquitoes has been funded by Projects from the European Union (EDEN, Eurowestnile and EDENext), Spanish Ministry of Health (EVITAR), Spanish Ministry of Economy and Competitivity (CGL2009-11445 and CGL2012-30759) and Junta de Andalucía (P07-RNM-02511 and P11-RNM-7038). Nicholas Johnson is funded by Defra grant SE4112 (Development of reseach tools to support arthropod-borne virus investigation). Anthony J. Wilson is funded by the Biotechnology and Biological Sciences Research Council (grant number BBS/B/00603).