Metagenomic discovery and co-infection of diverse wobbly possum disease viruses and a novel hepacivirus in Australian brushtail possums

Figures

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  Fig. 1. Histopathologic findings in Australian wobbly possum disease cases (hematoxylin and eosin). a Focal gliosis (black asterix), non-suppurative cellular infiltrates distending the leptomeninges (white asterix), and surrounding blood vessels (black arrowhead) within the brainstem. b Lymphocytes, plasma cells and scattered macrophages around a neural blood vessel. c Non-suppurative infiltrates in retrobulbar adipose tissue (black arrow), the perineurium of the optic nerve (black arrow head), and the scleral perivascular space (white arrow head). Retinal atrophy with an acellular ganglion cell layer (black asterix and inset). d Distention of the choroid layer with non-suppurative inflammation (arrow). e Optic nerve with Wallerian degeneration, illustrated by a macrophage within an axonal chamber (black arrowhead), and a non-suppurative perivascular infiltrate (white arrowhead)

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  Fig. 2. Identification of distinct lineages of WPDV in Australia. a Phylogenetic analysis of nucleotide sequences representing a partial (291 bp) replicase polyprotein 1ab region of WPDV, showing the NZ reference strains compared to the three Australian cases identified here. Two major lineages of the Australian viruses were identified - denoted Lineages 1 and 2 - and coloured in blue and red, respectively. Nodes show bootstrap values from 1000 replicates. The scale bar shows the number of nucleotide substitutions per site. b Pairwise comparisons of nucleotide similarity (%) across the viral genome

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  Fig. 3. Genome organisation and evolutionary relationships of WPDV to other arteriviruses. a Genome features and comparison of three lineages of WPDV - WPDV-AU1, WPDV-AU2 and WPDV-NZ (GenBank accession: NC_026811). b Phylogenetic analysis of the arterivirus RdRp protein. Nodes show bootstrap values obtained from 1000 replicates. Scale bar shows the number of amino acid substitutions per site. The tree was midpoint rooted for clarity only. c Pairwise nucleotide similarities (%) among the three WPDVs

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  Fig. 4. Evolutionary relationships of the novel hepacivirus identified from brushtailed possums. a Genome depiction of possum hepacivirus compared to its closest relative - Norway rat hepacivirus 2 (GenBank accession: NC_025673). b Phylogenetic analysis of the polyprotein gene (RdRp protein) of hepaciviruses. The novel possum hepacivirus is shown in red. Bootstrap values > 70% are shown for key nodes (1000 replicates). The tree was midpoint rooted for clarity only. The scale bar shows the number of amino acid substitutions per site