Invasive Alien Species of European Union Concern: A Systematic Review of High-Priority Pathogens in 22 Species in a...

Invasive alien species (IAS) not only threaten biodiversity and ecosystems but also play a significant role in the spread of infectious diseases; however, the epidemiological role of many IAS remains poorly understood. This study presents the first systematic review of major pathogens reported in 22 IAS of concern to the European Community. Given the breadth of available data, we relied on a literature search including studies reporting natural infections in target IAS, excluding experimental infections and non-target species. A total of 541 publications between 1963 and 2023 were analyzed, identifying 472 pathogens, of which 64 were classified as high-priority based on key global and European frameworks. IAS with broader distribution and higher research effort were associated with greater pathogen richness, suggesting potential epidemiological relevance but also highlighting detection bias. A composite Host-Pathogen Influence Index (HPI-IAS) revealed spatial heterogeneity in epidemiological pressure across Europe, with Poland, Germany, Italy, and France identified as areas of elevated epidemiological concern. These findings underscore the urgent need for coordinated, cross-border monitoring strategies at the European level and contribute to a broader understanding of IAS-related infectious disease ecology within a One Health framework.