Whole-genome analysis of piscine reovirus (PRV) shows PRV represents a new genus in family Reoviridae and its genome segment S1 sequences group it into two separate sub-genotypes

Abstract

BackgroundPiscine reovirus (PRV) is a newly discovered fish reovirus of anadromous and marine fish ubiquitous among fish in Norwegian salmon farms, and likely the causative agent of heart and skeletal muscle inflammation (HSMI). HSMI is an increasingly economically significant disease in Atlantic salmon (Salmo salar) farms. The nucleotide sequence data available for PRV are limited, and there is no genetic information on this virus outside of Norway and none from wild fish.MethodsRT-PCR amplification and sequencing were used to obtain the complete viral genome of PRV (10 segments) from western Canada and Chile. The genetic diversity among the PRV strains and their relationship to Norwegian PRV isolates were determined by phylogenetic analyses and sequence identity comparisons.ResultsPRV is distantly related to members of the genera Orthoreovirus and Aquareovirus and an unambiguous new genus within the family Reoviridae. The Canadian and Norwegian PRV strains are most divergent in the segment S1 and S4 encoded proteins. Phylogenetic analysis of PRV S1 sequences, for which the largest number of complete sequences from different “isolates” is available, grouped Norwegian PRV strains into a single genotype, Genotype I, with sub-genotypes, Ia and Ib. The Canadian PRV strains matched sub-genotype Ia and Chilean PRV strains matched sub-genotype Ib.ConclusionsPRV should be considered as a member of a new genus within the family Reoviridae with two major Norwegian sub-genotypes. The Canadian PRV diverged from Norwegian sub-genotype Ia around 2007 ± 1, whereas the Chilean PRV diverged from Norwegian sub-genotype Ib around 2008 ± 1.

Full-Genome Sequencing and Confirmation of the Causative Agent of Erythrocytic Inclusion Body Syndrome in Coho Salmon Identifies a New Type of Piscine Orthoreovirus

“…It is noteworthy that electron microscopic images of the cytoplasmic inclusions of PRV in Atlantic salmon erythrocytes strongly resemble those reported in coho salmon erythrocytes during EIBS [10, 14, 15]. PRV belongs to the family Reoviridae , subfamily Spinareovirinae , and has been proposed as a first member of a new genus within the family Reoviridae [16]. It is a double-stranded nonenveloped RNA virus with 10 genomic segments [17].…”

“…Kibenge et al . (2013) [16] grouped the Norwegian PRV isolates into a single genotype, genotype I, with subgenotypes Ia and Ib. The Canadian PRV isolates matched sub-genotype Ia and Chilean PRV isolates from Atlantic salmon matched sub-genotype Ib [16].…”

“…(2013) [16] grouped the Norwegian PRV isolates into a single genotype, genotype I, with subgenotypes Ia and Ib. The Canadian PRV isolates matched sub-genotype Ia and Chilean PRV isolates from Atlantic salmon matched sub-genotype Ib [16]. This classification appears to be very stable because further Norwegian PRV segment S1 sequences [18] supported this grouping [15, 19].…”

Population biology of infectious diseases shared by wild and farmed fish

“…Parasite dispersal connects the population dynamics of disease among farms within a region as well as between farmed salmon and the wild salmon populations that migrate through the aquaculture regions as juveniles and as adults. flammation disease; Palacios et al 2010) are considered exotic to the North Pacific Ocean, but PCR tests of farmed and wild salmon have indicated that strains of these ancestrally Norwegian viruses may now be present in both wild and farmed salmon in British Columbia (Kibenge et al 2013(Kibenge et al , 2016Marty et al 2015). These examples underscore the need for continuing and increasing biosecurity practices that focus on the trade and movement of seafood products -including aquaculture products, feed, eggs, and broodstock -at regional and global scales.…”

Virus genomes and virus-host interactions in aquaculture animals

“…At least 15 reovirus genomes have been completely sequenced (Table 2). Of these, 11 reoviruses are different isolates from cultured grass carp obtained in various years and from different regions [85,[87][88][89][90][91][92]; the other four reoviruses were isolated from cultured golden shiner, chum salmon, Atlantic salmon (Piscine reovirus), and turbot (Scophthalmus maximus reovirus), respectively [93][94][95].…”