Viral metagenomics reveals persistent as well as dietary acquired viruses in Antarctic fur seals

Abstract

Viruses linked to animals inhabiting Antarctic latitudes remain poorly studied. Remote environments hosting large pinniped populations may be prone to exposure of immunologically naïve animals to new infectious agents due to increasing human presence or introduction of new animal species. Antarctic fur seals (Arctocephalus gazella) inhabiting the Western Antarctic Peninsula and the South Shetland Islands are challenged because of climate change and increased anthropogenic activity. In the present study, the fecal and serum virome of A. gazella was characterized by applying target enrichment next generation sequencing. The resulting viromes were dominated by CRESS-DNA sequences. Viruses known to infect vertebrate and invertebrate hosts were also observed in fecal samples. Fur seal picornavirus was present in all the fecal pools studied suggesting it is a prevalent virus in these species. Six different viruses presenting similarities with previously described A. gazella viruses or other otariids and mammal viruses were identified as potential new A. gazella viruses. Also, diet-derived viruses such as crustacean viruses were present in fecal content. Penguin viruses, but not fish viruses, were also detected. Obtained results contribute to a better understanding of the viral community present in these species, which is relevant for its conservation.

Figure 1

Host distribution of viral assignations sequenced from fecal (A) and serum (B) samples collected from male A. gazella.

Figure 2

Nucleotide alignment of ORF2 sequences from the A. gazella picorna-like contigs compared to the ORF2 from RefSeq NC_0351110. In consensus strain, position 1 represents position 6523 from RefSeqs genome.

Figure 3

Phylogenetic consensus tree based on partial ORF2 sequences from the Mamastrovirus contigs sequenced from A. gazella scats (in bold). Bootstrap resampling with 1000 replicates.

Figure 4

Phylogenetic consensus tree of the Adeno-associated virus contigs sequenced from A. gazella scats (in bold). Bootstrap resampling with 1000 replicates.

Figure 5

Phylogenetic consensus tree of the Norovirus contig sequenced from A. gazella scats (in bold). Bootstrap resampling with 1000 replicates.

Figure 6

Map of the study area showing the Deception Island sampling location in the South Shetland Islands archipelago (Antarctic Peninsula). Map was created using the free software QGIS 3.10 (QGIS Development Team, 2018).