Forest cover influences the fecal virome of Oligoryzomys nigripes in Atlantic Forest remnants, Brazil.

Landscape changes driven by human activities can alter host-pathogen interactions, favoring generalist mammal species that act as reservoirs for zoonotic pathogens, potentially leading to spillover events and outbreaks. Here, we investigated how forest cover influences viral diversity in Oligoryzomys nigripes, a generalist rodent known to harbor zoonotic viruses in the Brazilian Atlantic Forest. We employed high-throughput sequencing to explore the fecal virome of 20 specimens collected across three landscapes with varying forest cover (20 %, 40 %, and 60 %) within Atlantic Forest fragments in São Paulo state. We identified 48 viral families, predominantly bacteriophages and vertebrate-associated viruses. Some, found for the first time in this host, exhibited zoonotic potential, including Papillomaviridae, Herpesviridae, Polyomaviridae, Adenoviridae, Alloherpesviridae, Arenaviridae, Paramyxoviridae, Peribunyaviridae, and Picornaviridae. Alpha and beta diversity indices were used to assess the viral community structure. Although alpha diversity indices did not show a statistically significant difference among landscapes, a significant compositional difference in viral community was detected through beta diversity index (Jaccard dissimilarity), indicating that forest cover may shape the composition of viral families present. The presence of a core virome shared across all landscapes, including families with pathogenic potential, reinforces O. nigripes role as a natural reservoir. While forest cover influences viral community structure, it doesn't necessarily reflect greater ecological complexity within fragments, indicating that other landscape-related factors must also be considered. This pioneering study characterizes the fecal virome of O. nigripes, revealing how forest cover may shape viral communities in wild rodents and underscoring their potential for zoonotic virus surveillance.