Novel avian papillomaviruses identified in a south polar skua sampled on Ross Island, Antarctica.

Papillomaviruses are small circular DNA viruses that infect epithelial cells of their hosts. Avian papillomaviruses are poorly sampled/documented compared to those infecting humans. We used a viral metagenomic approach to identify viruses from the oral swab taken from a deceased south polar skua (Stercorarius maccormicki) found at Cape Royds, Ross Island, Antarctica in late 2024. We identified three papillomaviruses and determined their complete genomes, Stercorarius maccormicki papillomavirus (SmacPV) 1-3. SmacPV1 is the most divergent of the three SmacPVs, sharing 62% genome-wide pairwise identity to SmacPV2 and SmacPV3 and <63.5% to other avian papillomaviruses. The genomes of SmacPV2 and SmacPV3 represent two new papillomavirus types sharing 82.4% genome-wide pairwise identity with each other and <72% to other papillomaviruses. SmacPV2 and SmacPV3 phylogenetically cluster with sequences of the Rissa tridactyla papillomavirus 1 from black-legged kittiwake (Rissa tridactyla), Larus smithsonianus papillomavirus 1 from American herring gull (Larus smithsonianus) and Fratercula arctica papillomavirus 1 from Atlantic puffin (Fratercula arctica), and they collectively represent a new papillomavirus species. These are the first papillomaviruses to be identified in Stercorarius spp. and add to the handful of known papillomaviruses in identified avian species. We also expand the known host range of papillomaviruses in Antarctic animals, which previously included Adélie penguins (Pygoscelis adeliae), Weddell seals (Leptonychotes weddellii), Antarctic fur seals (Arctocephalus gazella), leopard seals (Hydrurga leptonyx) and emerald notothen (Trematomus bernacchii).