Rattus norvegicus and Rattus tanezumi as hub hosts for viral diversity and potential spillover on Hainan Island,...

Rodents, which account for over 40% of mammalian species and occupy diverse terrestrial ecosystems, are major reservoirs for zoonotic viruses, including Coronaviridae, Hantaviridae, and Arenaviridae. However, the rodent species acting as central hubs for viral diversity and transmission remain poorly defined. To address this, we conducted systematic sampling across 18 counties and cities on Hainan Island between 2023 and 2024. A total of 2550 animals were collected, representing 14 Rodentia species, one Erinaceomorpha species, and one Scandentian species. Based on a statistical sampling framework, 1284 individuals were selected to generate 125 pooled gut samples for virome analysis. We identified 527 viral RNA species and recovered 175 complete or near-complete viral genomes. Remarkably, Rattus norvegicus and Rattus tanezumi accounted for 83.9% (442/527) of detected viral species, 68.6% (72/105) of novel viral sequences, and 88.6% (93/105) of cross-species viruses. Eight novel viruses showed recombination signals, seven originating from these two species. Among 13 human pathogenic viruses identified, 12 were detected in Rattus norvegicus and Rattus tanezumi. These findings suggest that these species may function as hub hosts for viral maintenance and spread, emphasizing the value of targeted surveillance to reduce future potential spillover risks.