Poliómavírus első kimutatása Magyarországra visszatelepített eurázsiai hód (Castor fiber) mintájából

Abstract

Background: The Eurasian beaver (Castor fiber), the largest rodent on the Eurasian continent, is considered a native species in Hungary. It faced extinction due to overhunting in 1865 but was successfully reintroduced in the subsequent years through migration and deliberate repopulation efforts. The population grew steadily, resulting in an estimated 8,500 individuals in 2019. Despite these developments, the viral presence in the growing beaver population has not been extensively studied. Objectives: This study aimed to assess the presence of polyomaviruses (PyVs) in the native Hungarian beaver population, to identify and characterize novel PyVs that can be detected in these mammals. Materials and Methods: Molecular analysis was applied to investigate the presence of PyVs in two Eurasian beavers that died in Hungary in 2019. From the specimens, liver, spleen and kidney tissues were sampled. A nested PCR was used to amplify a conserved region of the major capsid protein-encoding VP1 gene. Short DNA amplicons were sequenced using the Sanger method. Phylogenetic tree was calculated by Maximum Likelihood estimation, using PhyML software, based on VP1 amino acid sequences. Results and Discussion: An unknown PyV was detected in both beaver samples tested, the first identification of PyV in beavers globally. The detected virus is recommended to be named as Castor fiber polyomavirus 1, and it is likely represents the first member of a new PyV species. Phylogenetic analysis revealed that this new PyV belongs to the genus Alphapolyomavirus and forms a distinct clade with PyVs from different shrew species. This clade is clearly separate from other rodent PyVs, indicating a unique evolutionary history. However, the exact relationship and potential impact of this PyV on beaver health remain uncertain. Given the potential of PyVs to act as facultative pathogens under specific conditions, further research is needed to determine the extent of their role in beaver viral diseases.