First Report of Canine Bufavirus and Its Whole Genome Sequence in India

Canine bufavirus (CaBuV), a novel protoparvovirus of dogs was reported only in Italy and China, till date. It was detected from dogs with enteric and respiratory symptoms and is distantly related to the human bufavirus. To explore the enteric prevalence of CaBuV in India, 186 diarrheic faecal samples were collected in Telangana State between 2019 and 2020. Among the samples, 4.3% (8/186) were positive for CaBuV by PCR. Co-infection with canine parvovirus CPV-2 was seen in 75% (6/8) of CaBuV positive samples. The near complete genome (4292 bp) of CaBuV was amplified and reconstructed for one isolate 407/PVNRTVU/2020. Sequence alignment indicated 93.42–98.81% homology with the other available CaBuV sequences; 70.88-73.39%, and 54.4-54.8% identity with human bufavirus, and CPV-2, respectively. Phylogenetic analysis showed that CaBuV 407/PVNRTVU/2020 was most closely related to CaBuV Chinese strains, together separated as Asian lineage. All Bufaviruses clustered together in one clade; however, the bat and sea otter parvoviruses also showed close relation with Bufaviruses. This first report of prevalence of CaBuV in India provides a good reference, emphasizes the need for further epidemiological surveillance of CaBuV in India and its role in canine enteritis.

Archaeological and Contemporary Evidence Indicates Low Sea Otter Prevalence on the Pacific Northwest Coast During the Late Holocene

The historic extirpation and subsequent recovery of sea otters (Enhydra lutris) have profoundly changed coastal social-ecological systems across the northeastern Pacific. Today, the conservation status of sea otters is informed by estimates of population carrying capacity or growth rates independent of human impacts. However, archaeological and ethnographic evidence suggests that for millennia, complex hunting and management protocols by Indigenous communities limited sea otter abundance near human settlements to reduce the negative impacts of this keystone predator on shared shellfish prey. To assess relative sea otter prevalence in the Holocene, we compared the size structure of ancient California mussels (Mytilus californianus) from six archaeological sites in two regions on the Pacific Northwest Coast, to modern California mussels at locations with and without sea otters. We also quantified modern mussel size distributions from eight locations on the Central Coast of British Columbia, Canada, varying in sea otter occupation time. Comparisons of mussel size spectra revealed that ancient mussel size distributions are consistently more similar to modern size distributions at locations with a prolonged absence of sea otters. This indicates that late Holocene sea otters were maintained well below carrying capacity near human settlements as a result of human intervention. These findings illuminate the conditions under which sea otters and humans persisted over millennia prior to the Pacific maritime fur trade and raise important questions about contemporary conservation objectives for an iconic marine mammal and the social-ecological system in which it is embedded.

Skeletal muscle thermogenesis enables aquatic life in the smallest marine mammal

Basal metabolic rate generally scales with body mass in mammals, and variation from predicted levels indicates adaptive metabolic remodeling. As a thermogenic adaptation for living in cool water, sea otters have a basal metabolic rate approximately three times that of the predicted rate; however, the tissue-level source of this hypermetabolism is unknown. Because skeletal muscle is a major determinant of whole-body metabolism, we characterized respiratory capacity and thermogenic leak in sea otter muscle. Compared with that of previously sampled mammals, thermogenic muscle leak capacity was elevated and could account for sea otter hypermetabolism. Muscle respiratory capacity was modestly elevated and reached adult levels in neonates. Premature metabolic development and high leak rate indicate that sea otter muscle metabolism is regulated by thermogenic demand and is the source of basal hypermetabolism.