For a few years, a series of traditionally tropical mosquito-borne diseases, such as chikungunya fever and dengue, have posed challenges to national public health authorities in the European region. Other diseases have re-emerged, e.g. malaria in Greece, or spread to other countries, e.g. West Nile fever. These diseases are reportable within the European Union (EU), and the European Centre for Disease Prevention and Control collects information in various ways to provide EU member states with topical assessments of disease threats, risks and trends for prompt and appropriate public health action. Using disease-specific expert networks, the European Surveillance System (TESSy) collects standardized comparable information on all statutory communicable diseases in a database. In addition, the event-based surveillance aims to detect potential public health threats early, and to allow timely response and support to blood deferral decisions for pathogens that can be transmitted through blood donation. Laboratory capacity for early detection is implemented through external quality assessments. Other activities include the development of guidelines for the surveillance of mosquito vectors, and the production of regularly updated maps on the currently known occurrence of mosquito vector species.