Identification and mapping of potential and highly likely vectors for selected vector-borne diseases in the EU and neighbouring countries.

This report addresses Term of Reference 1.2 by providing a comprehensive knowledge-mapping of arthropod vector species competent to transmit selected vector-borne diseases (VBDs) including VBDs listed under Regulation (EU) 2016/429 and Regulation (EU) 2020/687, as well as additional non-listed pathogens with potential epidemiological relevance. The objective was to update and consolidate evidence on biological vector competence, mechanical transmission and vector geographic distribution for 25 selected VBDs in support of subsequent EU-level risk-assessment activities. Biological vector competence was assessed through two systematic literature reviews (SLRs), one focusing on pathogen detection in field-collected arthropods and the other on laboratory infection and transmission studies, while mechanical transmission was evaluated through a narrative literature review using predefined hierarchical criteria to classify vector likelihood. Geographic distribution data were updated via a third dedicated living SLR feeding into the VectorNet mapping workflow. Evidence from all reviews was synthesised, and expert judgement was applied where necessary to address data gaps. Literature reviews were conducted at global level, whereas geographic distribution maps were provided for vector species occurring in the EU and neighbouring countries, where available. The SLRs identified arthropod species with a highly likely biological vector competence for eight pathogens, supported by convergent field and laboratory evidence, and potential biological vectors for a further 16 pathogens based on evidence from either field or laboratory studies; for all these pathogens, at least one relevant vector species occurs in the EU or neighbouring regions and EU-level distribution maps are available. For a limited number of pathogens (5), no eligible biological vectors occurring in the EU were identified and expert judgement was therefore applied to identify plausible vectors. For mechanical transmission, the narrative review identified three pathogens associated with highly likely and four pathogens with potential mechanical vectors occurring in the EU or neighbouring countries, while expert judgement was required for two pathogens. Although EU-level distribution maps are not available for mechanically transmitted vectors, their widespread occurrence means geographic distribution is not considered a limiting factor for risk assessment. Evidence gaps remain for several pathogen-vector associations and will be further considered in subsequent assessments.