Athropod vectors and their growing importance in Europe

After the eradication of malaria in the middle of the past century, Europe felt relatively safe from vector-borne diseases due to the availability of effective insecticides and progress in medical diagnostics and treatment. In fact, except for Lyme disease, no vector-borne disease of cross-national distribution and far-reaching epidemiological relevance has been registered in Europe for decades. Nevertheless, not only have microorganisms with pathogenic potential increasingly been found to circulate among haematophagous arthropod populations but indigenous arthropods have also been demonstrated to possess vector competence for one pathogen or the other. Also, single cases and even localized outbreaks of mosquito-borne and further tick-borne diseases have occurred. But only in the last 10-20 years or so, probably as a consequence of ecological and climatic changes as well as of continuing globalization, some alarming vector- and vector-borne disease-related developments have taken place in Europe: the establishment and spread of invasive arthropod-vectors of disease, the importation of vector-associated pathogens, and outbreaks of emerging vector-borne diseases. The most striking examples of these incidents are the bluetongue disease epidemic in central Europe which started in 2006, and the chikungunya fever outbreak in Italy in 2007. In the first case, indigenous biting midges that had previously not been known to be vector-competent served as bluetongue virus vectors, while in the second case a human traveller carrying chikungunya virus infected vector-competent Aedes albopictus mosquitoes that had established in Italy some years before and had been spreading since then. In this contribution, major trends of the recent past concerning arthropod-vectors and the disease agents they transmit in Europe are reviewed. Because of their growing scientific importance and increasing public attention, the focus will be on mosquito, tick, sandfly and biting midge vectors.