Characterization of a Novel, Highly Divergent Paramyxovirus Discovered in a Bearded Seal of Subarctic Canada

Seals are keystone animals in the Arctic and a valuable resource for Indigenous communities, but their virome is poorly understood. Through a preliminary investigation of the virome of seven North Atlantic bearded seals (Erignathus barbatus) from northwest Newfoundland, Canada, we discovered a new member of the Paramyxoviridae, a family including important animal pathogens. The complete coding genome sequence (15,898 nt) of the novel paramyxovirus, which we named bearded seal-associated paramyxovirus 1 (BSAPV-1), encoded five core paramyxoviral proteins-nucleoprotein, matrix, fusion, hemagglutinin-neuraminidase, and polymerase-and three proteins with no identifiable homologues that may represent the phosphoprotein, a small hydrophobic protein, and a transmembrane protein. Phylogenetic analysis, including BSAPV-1 and all 153 currently known paramyxoviral species, positioned the novel virus in a long-branched clade with Wenzhou Pacific spadenose shark paramyxovirus (Skoliovirinae, Scoliodonvirus scoliodontis), its closest relative (pairwise identity of the L protein: 30.1%). According to ICTV criteria, BSAPV-1 is likely the first member of a novel paramyxoviral subfamily. As the virus was found in combined tracheal/fecal swabs of a single animal, we could not conclude whether this is a seal virus or a virus associated with seal food. This study expands our knowledge about marine paramyxoviruses, and future studies should investigate BSAPV-1 ecology, spread, and host spectrum.