Genotypic differentiation and evolutionary dynamics of puumala orthohantavirus (PUUV)

Puumala orthohantavirus (PUUV) is a causative agent of haemorrhagic fever with renal syndrome, mainly transmitted through rodent excretions. Classification of PUUV has traditionally been based on the geographic locations of their discovery, but this system faces challenges due to inconsistencies between the names of lineages and their actual distribution. In this study, we propose a quantitative criterion of “10% nucleotide difference” to distinguish PUUV genotypes, resulting in a subdivision of PUUV into twenty-one distinct genotypes. The application of this criterion suggested a further division of the CE, RUS, FIN and N-SCA lineages and was consistent with the current taxonomic position of the S-SCA, LAT, DAN and ALAD lineages. In addition, analysis of reassortment and recombination events showed that PUUV undergoes these processes, but they are relatively rare. Our results emphasise the importance of considering genetic distances in the classification of PUUV and provide a robust criterion for subspecies-level taxonomy.