Phylogenomic analysis of the complete sequence of a gastroenteritis-associated cetacean adenovirus (bottlenose dolphin adenovirus 1) reveals a high degree of genetic divergence

A Novel Adenovirus Detected in Bering-Chukchi-Beaufort Seas Bowhead Whale (Balaena mysticetus): Epidemiologic Data and Phylogenetic Characterization

Adenoviruses are common pathogens infecting a wide range of vertebrates. Few cetacean adenoviruses have been described in the literature, and their pathogenicity is still unclear. Using PCR-based viral and bacterial pathogen surveillance in Bering-Chukchi-Beaufort seas bowhead whales (Balaena mysticetus) legally harvested 2012-15 during Alaskan aboriginal subsistence hunts, six of 59 bowhead whales (10%) tested positive for adenovirus DNA in the spleen. We found a high degree of sequence divergence from other mastadenoviruses, suggesting these may represent a novel species, tentatively named bowhead whale adenovirus. The sequences detected are distinct from adenoviruses previously identified in bottlenose dolphins (Tursiops truncatus) and harbor porpoises (Phocoena phocoena), forming two distinct clades in the cetacean hosts. The clinical impact is unclear, since no histopathologic evidence of adenovirus-associated disease was found. Furthermore, detection of adenovirus DNA in the spleen, contrary to other cetacean adenoviruses detected in the intestinal tract, may suggest a broader tissue tropism. Our study demonstrates adenovirus infection in bowhead whales and the usefulness of molecular diagnostics to discover and genetically characterize novel viruses in marine mammals.

Circular DNA viruses identified in short-finned pilot whale and orca tissue samples

Members of the Delphinidae family are widely distributed across the world's oceans. We used a viral metagenomic approach to identify viruses in orca (Orcinus orca) and short-finned pilot whale (Globicephala macrorhynchus) muscle, kidney, and liver samples from deceased animals. From orca tissue samples (muscle, kidney, and liver), we identified a novel polyomavirus (Polyomaviridae), three cressdnaviruses, and two genomoviruses (Genomoviridae). In the short-finned pilot whale we were able to identify one genomovirus in a kidney sample. The presence of unclassified cressdnavirus within two samples (muscle and kidney) of the same animal supports the possibility these viruses might be widespread within the animal. The orca polyomavirus identified here is the first of its species and is not closely related to the only other dolphin polyomavirus previously discovered. The identification and verification of these viruses expands the current knowledge of viruses that are associated with the Delphinidae family.