Identification of Reassortant Mammalian Orthoreovirus Strains in European Hedgehogs (Erinaceus europaeus): Genomic Insights and Host Association

Thanks to its ethological and physiological characteristics, the hedgehog is a synanthropic species of particular importance for the maintenance and possible spread of pathogens, some of which are zoonotic. Among these, we can include the mammalian orthoreovirus (MRV), which is characterized by respiratory, gastrointestinal, and neurological symptoms in both animals and humans. MRV is characterized by a high capacity for genetic reassortment and intragenic rearrangement, and the ability to infect a wide range of mammals. This work aims to investigate the presence of MRVs and its genomic characterization in hedgehogs. During the two-year period from 2022 to 2023, the intestine and lungs were collected from 293 hedgehogs and subjected to real-time PCR to detect the L1 gene. Positive samples were subjected to a typing RT-PCR targeting a portion of the S1 gene and then to sequencing. A total of 38 hedgehogs tested positive by real-time PCR (p = 13%). Typing RT-PCR demonstrated the positivity of 25 samples for serotype 3. Four samples, representative of the main groups recognized during the phylogenetic analysis, underwent whole genome sequencing, revealing the presence of reassortment phenomena between strains related to bats, chamois, and human MRVs.