Distribution borders of Puumala orthohantavirus in its rodent reservoir in Germany

Puumala orthohantavirus (PUUV) causes the majority of human hantavirus disease cases in Germany. The frequency of human cases is mainly driven by the abundance and prevalence of PUUV in the natural reservoir, the bank vole (Clethrionomys glareolus). The objective of our study within the research consortium “RoBoPub” (Rodent-Borne-Pathogens-and-Public-Health) is to further characterize the PUUV range in Germany. For that purpose, bank voles were collected along large scale transects in North Rhine-Westphalia/Lower Saxony and within Thuringia and Bavaria. Between 2018-21 2873 bank voles were collected and screened for PUUV-specific RNA and antibodies. In spring, the average PUUV prevalence reached 14% to 16% in non-outbreak years and 17% to 92% in outbreak years (2019 and 2021). The investigation in Lower Saxony confirmed the range border reaching from district Bentheim to district Osnabrück in the northwest of Germany. In Thuringia PUUV occurrence in bank voles was sporadic and geographically restricted to certain forest areas in the northwest and southwest. Preliminary data from Bavaria suggest the absence of PUUV within the central region despite widespread presence of the pathogen in Bavaria’s north and east. Future investigations are needed to identify the reasons for the current PUUV distribution in Thuringia and Bavaria. The identification of PUUV endemic regions based on reservoir screening will help to establish geographically specified risk assessments for the public.