Identification of aviadenovirus and dependoparvovirus in an Adélie penguin fecal sample from Cape Royds (Ross Island, Antarctica).

Adenoviruses (Adenoviridae) and their associated replication-deficient dependoparvoviruses (Parvoviridae) are recognized as significant components of the avian virome. While well-studied in domestic birds, these viruses remain underexplored in wild Antarctic birds. Information is limited on viruses circulating in penguins, particularly outside of the Antarctic Peninsula Region. Here we leverage a fecal sample collected for diet analyses to identify an aviadenovirus (37,731 nt) and two distinct dependoparvoviruses. The Adélie penguin (Pygoscelis adeliae) feces-derived adenovirus exhibits a genome organization consistent with members of the genus Aviadenovirus but shares only ~64% amino acid identity in the DNA polymerase protein with its closest known relative and thus represents a new species of aviadenovirus identified in penguins. Additionally, we identified two new dependoparvoviruses, one in length of 4,869 nt and a second of 4,162 nt. These two dependoparvoviruses are diverse, sharing <61% Rep amino acid identity with those of other dependoparvoviruses. Penguin dependoparvovirus 1 represents a new species. The co-detection of these viruses in a single seasonal sample could suggest a potential helper-satellite relationship in Adélie penguins. This study provides the first evidence of aviadenoviruses in Adélie penguin feces. These findings highlight the importance of surveillance to understand pathogen dynamics in isolated Antarctic populations.