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International audience; Background: Serological screening tests for Lyme borreliosis have poor specificity, with potential for misdiagnosis and unnecessary antimicrobial treatment.Objectives: To evaluate the impact of Lyme borreliosis seroprevalence and serologic test characteristics on the probability of obtaining a false-positive result and impact on antimicrobial use.Study design: Cross-sectional serological survey and modelling.Methods: Sera from 303 horses in southern Belgium were analysed by enzyme-linked immunosorbent assay (ELISA). Apparent seroprevalence was derived from serological data and a Bayesian estimate of true seroprevalence was computed. These were a starting point to model the impact of test and population characteristics on the probability of obtaining false-positive results and consequently unnecessary treatments and complications.Results: Apparent and true seroprevalence were 22% (95% CI 18%-27%) and 11% (credible interval with 95% probability 0.6%-21%) respectively. We estimate that two-thirds of positive samples are false positive in southern Belgium, with one in five of tested horses potentially misdiagnosed as infected. Around 5% of antimicrobial use in equine veterinary practice in Belgium may be attributable to treatment of a false-positive result.Main limitations: There was uncertainty regarding the ELISA's sensitivity and specificity.Conclusions: This study highlights the importance of appreciating the poor diagnostic value of ELISA screening for Lyme borreliosis as demonstrated by this case study of seroprevalence in southern Belgium where we demonstrate that a nontrivial number of horses is estimated to receive unwarranted treatment due to poor appreciation of screening test characteristics by practitioners, contributing substantially to unnecessary use of antimicrobials.

International audience; The present study is a component of a major European research project, ICONZ (Integrated Control of Neglected Zoonoses). The objective of this component was to implement, and then evaluate an Integrated Control Intervention (ICI) against three dog transmitted zoonoses, namely rabies, visceral leishmaniasis, and cystic echinococcosis. This was undertaken in Sidi Kacem Province (northwestern Morocco) where 22 control and 22 treated douars (villages) were randomly allocated to two control and one evaluation interventions over a period of 13 months. Across the 44 douars, an overall total of 6922 dogs were registered, 4519 were vaccinated against rabies, and 2885 persons attended the complementary health education campaigns; whereas, within the 22 treated douars, 466 dogs received anti-sandfly collars (deltamethrin-impregnated) and 2487 were dewormed (praziquantel). Evaluation of the ICI, revealed that (i) a canine rabies vaccination coverage of 65.0% was achieved, (ii) the use of deltamethrin-impregnated collars for dogs provided highly significant protection (p = 0.01) against leishmaniasis infection of more than 44%, and up to 100% for dogs that had kept the collar until the end of the intervention, (iii) despite a non-significant difference (p>0.05), dog-deworming with praziquantel yielded a reduction in the rate of Echinococcus granulosus infection, and (iv) health education was successful in improving respondents’ knowledge; However, the target communities remained unconvinced of the necessity of changing some of their risky behaviours. Lastly, the estimated total cost of the global intervention, including its research components, was US$ 143,050, of which 67% was for disease control work with clear evidence of significant economies of scale due to targeting three diseases together. It appears from this study that the integrated control approach against the three zoonoses was effective on both economic and logistical levels.

Background Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are vectors of bluetongue virus (BTV), African horse sickness virus and Schmallenberg virus (SBV). Outbreaks of both BTV and SBV have affected large parts of Europe. The spread of these diseases depends largely on vector distribution and abundance. The aim of this analysis was to identify and quantify major spatial patterns and temporal trends in the distribution and seasonal variation of observed Culicoides abundance in nine countries in Europe. Methods We gathered existing Culicoides data from Spain, France, Germany, Switzerland, Austria, Denmark, Sweden, Norway and Poland. In total, 31,429 Culicoides trap collections were available from 904 ruminant farms across these countries between 2007 and 2013. Results The Obsoletus ensemble was distributed widely in Europe and accounted for 83% of all 8,842,998 Culicoides specimens in the dataset, with the highest mean monthly abundance recorded in France, Germany and southern Norway. The Pulicaris ensemble accounted for only 12% of the specimens and had a relatively southerly and easterly spatial distribution compared to the Obsoletus ensemble. Culicoides imicola Kieffer was only found in Spain and the southernmost part of France. There was a clear spatial trend in the accumulated annual abundance from southern to northern Europe, with the Obsoletus ensemble steadily increasing from 4000 per year in southern Europe to 500,000 in Scandinavia. The Pulicaris ensemble showed a very different pattern, with an increase in the accumulated annual abundance from 1600 in Spain, peaking at 41,000 in northern Germany and then decreasing again toward northern latitudes. For the two species ensembles and C. imicola, the season began between January and April, with later start dates and increasingly shorter vector seasons at more northerly latitudes. Conclusion We present the first maps of seasonal Culicoides abundance in large parts of Europe covering a gradient from southern Spain to northern Scandinavia. The identified temporal trends and spatial patterns are useful for planning the allocation of resources for international prevention and surveillance programmes in the European Union. Electronic supplementary material The online version of this article (10.1186/s13071-018-2706-y) contains supplementary material, which is available to authorized users.

International audience; Ticks are economically and medically important ectoparasites due to the injuries inflicted through their bite, and their ability to transmit pathogens to humans, livestock, and wildlife. Whereas hard ticks have been intensively studied, little is known about soft ticks, even though they can also transmit pathogens, including African Swine Fever Virus (ASFV) affecting domestic and wild suids or Borrelia bacteria causing tick-borne relapsing fever (TBRF) in humans. We thus developed a regional model to identify suitable spatial areas for a community of nine Ornithodoros tick species (O. erraticus, O. sonrai, O. alactagalis, O. nereensis, O. tholozani, O. papillipes, O. tartakovskyi, O. asperus, O. verrucosus), which may be of medical and veterinary importance in the Western Palearctic region. Multi-Criteria Decision Analysis was used due to the relative scarcity of high-quality occurrence data. After an in-depth literature review on the ecological requirements of the selected tick community, five climate related factors appeared critical for feeding activity and tick development: (i) a spring temperature exceeding 10 degrees C to induce the end of winter soft tick quiescent period, (ii) a three-months summer temperature above 20 degrees C to allow tick physiological activities, (iii) annual precipitation ranging from 60 mm to 750 mm and, in very arid areas, (iv) dry seasons interrupted by small rain showers to maintain minimum moisture inside their habitat along the year or (v) residual water provided by perennial rivers near habitats. We deliberately chose not to include biological factors such as host availability or vegetation patterns. A sensitivity analysis was done by performing multiple runs of the model altering the environmental variables, their suitability function, and their attributed weights. To validate the models, we used 355 occurrence data points, complemented by random points within sampled ecoregions. All models indicated suitable areas in the Mediterranean Basin and semi desert areas in South-West and Central Asia. Most variability between models was observed along northern and southern edges of highly suitable areas. The predictions featured a relatively good accuracy with an average Area Under Curve (AUC) of 0.779. These first models provide a useful tool for estimating the global distribution of Ornithodoros ticks and targeting their surveillance in the Western Palearctic region.

International audience; Emerging infectious diseases are of increasing concern worldwide and in particular in Europe. In a review, Jones et al. have shown that between 1940 and 2004, the majority of emerging infectious diseases occurred in areas with both a high mobility and high density of population, notably in Western Europe. Furthermore, nearly a third (29%) of the recorded events related to emerging infectious diseases were due to vector-borne diseases during the decade 1990-2000[1]. This issue of Eurosurveillance presents a series of review articles with a particular focus on arthropod-borne diseases transmitted by mosquitoes and phlebotomine sandflies. Each of the papers addresses a series of issues of common interest such as the relevance of the disease in the given context, its transmission and epidemiology, including the current geographical distribution, and clinical symptoms, diagnostic methods, treatment strategies and prevention methods. Furthermore, the papers describe factors triggering changes in distribution of the vectors and disease and risk prediction models. A review on West Nile virus by Reiter includes a fresh and innovative viewpoint on the epidemiology and transmission of the disease [2], and the same author contributed further with a twin-review on two diseases which have much in common: yellow fever and dengue [3]. Most importantly, both have a history of occurrence in Europe and vectors and pathogens are spreading through increased movement of persons and transport of goods. Chevalier et al. present a review on Rift Valley fever a mosquito-borne disease at Europe’s fringes. The epidemiology of Rift Valley fever is fascinating because of its complex cycle where the virus may remain dormant for many years and outbreaks involve both vector related and direct transmission. The disease may become a risk in the future in countries bordering the Mediterranean Sea, mainly through increased livestock trade. Two authors have contributed reviews on viruses transmitted by phlebotomine sandflies. Ready has written about Leishmania, a parasite of particular relevance to Europe because it is currently established around the Mediterranean Sea, but known to be spreading north [4]. Depaquit et al. have contributed a review on a number of less well known Phlebo-, Vesiculo- and Orbiviruses such as Sandfly fever Sicilian and Naples virus, Toscana virus Chandipura virus and others that are transmitted by sandflies in Europe and more specifically around the Mediterranean Sea [5]. The paper summarizes the current knowledge on these viruses which have a potential to spread throughout the distribution zone of their phlebotomine vectors in Europe. Both reviews provide a series of maps displaying country based information on the distribution of the disease. In addition to these papers, the issue features a perspective paper by Maltezou et al. presenting the present situation of Crimean-Congo hemorrhagic fever, a tick-borne disease, in Europe and emphasizing relevant aspects for preparedness concerning the potential spread of this disease in Europe in the future [6]. As will become clear from reading these reviews, often crucial knowledge is still missing which is needed to anticipate, prevent or prepare for the establishment and spread of vector-borne diseases. One of these is reliable information on the continent wide distribution of potential disease vectors. National presence-absence maps, as shown by Ready [4] and Depaquit [5] are a first step in this direction and need further refinement. In 2007-08, the European Centre for Disease Prevention and Control funded the V-borne project with the aim to identify and document vector-borne diseases relevant for public health in Europe, provide an overview of the existing relevant resources, carry out a qualitative multi-disciplinary risk assessment within the limits of the available information and data, and identify priorities for future prevention and control of vector borne diseases in Europe. Building on the expertise from this network, ECDC created a European network for arthropod vector surveillance for human public health, the VBORNET in 2009 [7]. The network will establish pan-European state of the art maps of validated vector distributions that can be used as basis for risk assessment studies thus contributing to preparedness for the emerge or re-emerge of vector-borne disease in Europe.