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This meta-analysis of reports examining ticks throughout the Western Palearctic region indicates a distinct geographic pattern for Borrelia burgdorferi sensu lato prevalence in questing nymphal Ixodes ricinus ticks. The greatest prevalence was reported between the 5°E and 25°E longitudes based on an analysis of 123 collection points with 37,940 nymphal tick specimens (87.43% of total nymphs; 56.35% of total ticks in the set of reports over the target area). Climatic traits, such as temperature and vegetation stress, and their seasonality correlated with Borrelia prevalence in questing ticks. The greatest prevalence was associated with mild winter, high summer, and low seasonal amplitude of temperatures within the range of the tick vector, higher vegetation indices in the May-June period, and well-connected vegetation patches below a threshold at which rates suddenly drop. Classification of the target territory using a qualitative risk index derived from the abiotic variables produced an indicator of the probability of finding infected ticks in the Western Palearctic region. No specific temporal trends were detected in the reported prevalence. The ranges of the different B. burgdorferi sensu lato genospecies showed a pattern of high biodiversity between 4°W and 20°E, partially overlapping the area of highest prevalence in ticks. Borrelia afzelii and Borrelia garinii are the dominant species in central Europe (east of ϳ25°E), but B. garinii may appear alone at southern latitudes and Borrelia lusitaniae is the main indicator species for meridional territories.

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The aim of this kinetic work is a critical and detailed analysis of the acetylene pyrolysis in a wide range of conditions, especially from 900 to 2500 K, in order to further validate and refine the kinetic mechanism of C2−C4 acetylenic species. In particular, the successive reactions of the intermediate products, such as C4 species and polyynes, were especially\ud investigated to better understand the primary C2H2 kinetics. The subsystem of acetylene pyrolysis reactions clearly constitutes an important portion in the overall kinetic scheme and also a crucial topic in the further extension of the model toward the formation of polycyclic aromatic hydrocarbons (PAHs) and soot particles. The analysis of acetylene experiments, often with the formation of large amount of soot, requires the coupling of the gas phase kinetic scheme with a soot kinetic model. The gas-phase kinetics involves the formation of the first polycyclic aromatic hydrocarbons up to the first components of the soot kinetic mechanism (C20H16 and C20H10). The soot kinetic model is based on a discrete sectional method with an extensive use of lumping rules. Analogy and similarity rules with gas phase kinetics are used to extend the soot mechanism up to the formation of species with more than 107 carbon atoms. The lumped approach, extensively applied in the kinetic modeling of large hydrocarbon species, becomes a necessity in treating chemical reacting systems of these dimensions. The analysis of the experimental data of acetylene pyrolysis obtained in a wide range of conditions permits us not only to highlight the competition between the molecular and the free radical pathways but also to analyze the successive condensation reactions for the formation of PAHs and the growing of soot particles

We applied a process-driven model to evaluate the impact of climate scenarios for the years 2020, 2050, and 2080 on the life cycle of Hyalomma marginatum ticks in the western Palearctic. The net growth rate of the tick populations increased in every scenario tested compared to the current climate baseline. These results support the expectations of increased tick survival and increased population turnover in future climate scenarios. We included a basic evaluation of host movement based on rules connected to altitude, slope, size of the near patches, and inter-patch distances in the real landscape over the target area. Data on landscape were obtained from medium-resolution MODIS satellite imagery, which allowed us to test the potential spread of the populations. Such a model of host dispersal linked to the process-driven life cycle model demonstrated that eastern (Turkey, Russia, and Balkans) populations of H. marginatum currently are well separated and have little mixing with western (Italy, Spain, and northern Africa) populations. The northern limit is marked by the cold areas in the Balkans, Alps, and Pyrenees. Under the warmer conditions predicted by the climate scenarios, the exchange of ticks throughout new areas, previously free of the vector, is expected to increase, mainly in the Balkans and southern Russia, over the limit of the mountain ranges. Therefore, the northern limit of the tick range would increase. Additional studies are necessary to understand the implications of host changes in range and abundance for H. marginatum and Crimean-Congo hemorrhagic fever virus.