Bat-Borne Viruses in Northern Europe: Current Knowledge, Regional Patterns, and Key Knowledge Gaps

Bats harbour a diverse range of viruses, including members of several viral families containing important human and animal pathogens, and have therefore become an important focus of research on emerging and re-emerging infectious diseases. While bat-associated viruses have been extensively investigated in several parts of the world, knowledge from temperate Northern Europe remains fragmented and geographically uneven. In this review, we summarize current knowledge of bat-associated viruses in Germany, Poland, Estonia, Latvia, Lithuania, Denmark, Norway, Finland and Sweden. We first consider the bat fauna and ecological connectivity of the region and provide an overview of reported viral diversity, followed by a review of major virus groups, including lyssaviruses, coronaviruses, astroviruses and nairoviruses, as well as other viruses identified through targeted and metagenomic surveillance. We further discuss the opportunities and limitations of metagenomic virus discovery, particularly the distinction between detection of viral sequences and evidence of true host association, and highlight major gaps in geographical coverage, longitudinal surveillance and biological characterization of newly identified viruses. Coordinated surveillance integrating virological, genomic and ecological data will be important for understanding the diversity, evolution and transmission of bat-associated viruses in Northern Europe and for evaluating their potential relevance to human and animal health.