ENDEMIC INFECTION OF STRANDED SOUTHERN SEA OTTERS (ENHYDRA LUTRIS NEREIS) WITH NOVEL PARVOVIRUS, POLYOMAVIRUS, AND ADENOVIRUS

Abstract

Over the past century, the southern sea otter (SSO; Enhydra lutris nereis) population has been slowly recovering from near extinction due to overharvest. The SSO is a threatened subspecies under federal law and a fully protected species under California law, US. Through a multiagency collaborative program, stranded animals are rehabilitated and released, while deceased animals are necropsied and tissues are cryopreserved to facilitate scientific study. Here, we processed archival tissues to enrich particle-associated viral nucleic acids, which we randomly amplified and deeply sequenced to identify viral genomes through sequence similarities. Anelloviruses and endogenous retroviral sequences made up over 50% of observed viral sequences. Polyomavirus, parvovirus, and adenovirus sequences made up most of the remaining reads. We characterized and phylogenetically analyzed the full genome of sea otter polyomavirus 1 and the complete coding sequence of sea otter parvovirus 1 and found that the closest known viruses infect primates and domestic pigs ( Sus scrofa domesticus), respectively. We tested archived tissues from 69 stranded SSO necropsied over 14 yr (2000-13) by PCR. Polyomavirus, parvovirus, and adenovirus infections were detected in 51, 61, and 29% of examined animals, respectively, with no significant increase in frequency over time, suggesting endemic infection. We found that 80% of tested SSO were infected with at least one of the three DNA viruses, whose tissue distribution we determined in 261 tissue samples. Parvovirus DNA was most frequently detected in mesenteric lymph node, polyomavirus DNA in spleen, and adenovirus DNA in multiple tissues (spleen, retropharyngeal and mesenteric lymph node, lung, and liver). This study describes the virome in tissues of a threatened species and shows that stranded SSO are frequently infected with multiple viruses, warranting future research to investigate associations between these infections and observed lesions.

Molecular detection and characterization of carnivore parvoviruses in free‐ranging Eurasian otters (Lutra lutra) in southern Italy

“…Several studies report that both FPV and CPV are able to infect free‐ranging species within the order Carnivora (Allison et al, , ; Canuti et al, ; Hoelzer, Shackelton, Parrish, & Holmes, ; Siqueira et al, ; Steinel, Parrish, Bloom, & Truyen, ). Free‐ranging species, particularly red foxes and raccoon, have been suggested to act as hosts for evolutionary intermediates between FPV and CPV (Parrish et al, ) and between CPV‐2 and CPV‐2a (Allison et al, ).…”

“…It is known that the river otters ( Lontra canadensis ) may be susceptible to CPV infection (Hoover, Castro, & Nieves, ; Kimber & Kollias, ). A CPV‐induced disease was reported in nine Asian small‐clawed otters ( Aonyx cinerea ) (Gjeltema, Murphy, & Rivera, ); and recently a novel parvovirus was detected in southern sea otters ( Enhydra lutris nereis ) (Siqueira et al, ).…”

Mustelids

“…Infection resulted in inappetence, lethargy, vomiting, and diarrhea, and one fatality (Gjeltsema et al, 2015). An endemic parvovirus has been identified in southern sea otters but no disease association has been established (Siqueira et al, 2017).…”

An ancient lineage of highly divergent parvoviruses infects both vertebrate and invertebrate hosts

“…Numerous novel parvoviruses have been identified in recent years, primarily via approaches based on high throughput sequencing (HTS) (5-11). In addition, progress in whole genome sequencing of eukaryotes has revealed that sequences derived from parvoviruses occur relatively frequently in animal genomes (12-17).…”