Mammal-infecting DNA viruses identified in lemurs and rodents in Madagascar mirror the evolutionary history of their hosts.

Given that some DNA viruses have been found to exhibit virus-host co-evolution and establish lifelong infection, mammals with unique evolutionary histories in island ecosystems likely host exceptionally diverse viruses. Madagascar is inhabited by endemic non-human primate and rodent lineages interacting with expansive populations of introduced non-native rodents across the island. Using a viral metagenomic workflow on 189 oral swabs of lemurs and rodents in southeastern Madagascar, we characterized genomic sequences of DNA viruses in the families Adenoviridae, Circoviridae, Orthoherpesviridae, Papillomaviridae, Parvoviridae and Polyomaviridae and assessed their phylogenetic relationships to known viruses. Endemic lemurs and tufted-tailed rats displayed particularly novel DNA viral diversity mirroring the geographic isolation and subsequently rich evolutionary history of their hosts. Notably, we provide the first coding-complete sequences in lemurs of herpesviruses, polyomaviruses, adeno-associated viruses and circoviruses. In contrast, the DNA viral communities of black rats in Madagascar were similar to those found in globally distributed black and brown rat populations, given their broad geographic spread and relatively recent introduction to the island. Given the scarcity of viral research in natural populations of lemurs and rodents in Madagascar despite the island's exceptional biodiversity and escalating anthropogenic pressures, this study provides a genomic and phylogenetic foundation for DNA viruses infecting Malagasy lemurs and rodents.