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[This corrects the article DOI: 10.1371/journal.pone.0141475.].
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Heart and skeletal muscle inflammation (HSMI) is a significant and often fatal disease of cultured Atlantic salmon in Norway. The consistent presence of Piscine orthoreovirus (PRV) in HSMI diseased fish along with the correlation of viral load and antigen with development of lesions has supported the supposition that PRV is the etiologic agent of this condition; yet the absence of an in vitro culture system to demonstrate disease causation and the widespread prevalence of this virus in the absence of disease continues to obfuscate the etiological role of PRV with regard to HSMI. In this study, we explore the infectivity and disease causing potential of PRV from western North America-a region now considered endemic for PRV but without manifestation of HSMI-in challenge experiments modeled upon previous reports associating PRV with HSMI. We identified that western North American PRV is highly infective by intraperitoneal injection in Atlantic salmon as well as through cohabitation of both Atlantic and Sockeye salmon. High prevalence of viral RNA in peripheral blood of infected fish persisted for as long as 59 weeks post-challenge. Nevertheless, no microscopic lesions, disease, or mortality could be attributed to the presence of PRV, and only a minor transcriptional induction of the antiviral Mx gene occurred in blood and kidney samples during log-linear replication of viral RNA. Comparative analysis of the S1 segment of PRV identified high similarity between this North American sequence and previous sequences associated with HSMI, suggesting that factors such as viral co-infection, alternate PRV strains, host condition, or specific environmental circumstances may be required to cause this disease.
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Doenças dos Peixes/virologia , Orthoreovirus/fisiologia , Infecções por Reoviridae/virologia , Salmo salar/virologia , Sequência de Aminoácidos , Animais , Cardiomiopatias/virologia , Doenças Endêmicas , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/transmissão , Interações Hospedeiro-Patógeno , Dados de Sequência Molecular , Músculo Esquelético/patologia , Músculo Esquelético/virologia , Miosite/virologia , América do Norte/epidemiologia , Orthoreovirus/classificação , Orthoreovirus/genética , Filogenia , Prevalência , RNA Viral/sangue , RNA Viral/genética , RNA Viral/metabolismo , Infecções por Reoviridae/epidemiologia , Infecções por Reoviridae/transmissão , Salmo salar/sangue , Homologia de Sequência de Aminoácidos , Fatores de TempoRESUMO
Piscine reovirus (PRV) is a double stranded non-enveloped RNA virus detected in farmed and wild salmonids. This study examined the phylogenetic relationships among different PRV sequence types present in samples from salmonids in Western Canada and the US, including Alaska (US), British Columbia (Canada) and Washington State (US). Tissues testing positive for PRV were partially sequenced for segment S1, producing 71 sequences that grouped into 10 unique sequence types. Sequence analysis revealed no identifiable geographical or temporal variation among the sequence types. Identical sequence types were found in fish sampled in 2001, 2005 and 2014. In addition, PRV positive samples from fish derived from Alaska, British Columbia and Washington State share identical sequence types. Comparative analysis of the phylogenetic tree indicated that Canada/US Pacific Northwest sequences formed a subgroup with some Norwegian sequence types (group II), distinct from other Norwegian and Chilean sequences (groups I, III and IV). Representative PRV positive samples from farmed and wild fish in British Columbia and Washington State were subjected to genome sequencing using next generation sequencing methods. Individual analysis of each of the 10 partial segments indicated that the Canadian and US PRV sequence types clustered separately from available whole genome sequences of some Norwegian and Chilean sequences for all segments except the segment S4. In summary, PRV was genetically homogenous over a large geographic distance (Alaska to Washington State), and the sequence types were relatively stable over a 13 year period.
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Doenças dos Peixes/genética , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Filogenia , Infecções por Reoviridae/genética , Reoviridae/genética , Salmonidae/genética , Sequência de Aminoácidos , Animais , Animais Selvagens , Sequência de Bases , Canadá/epidemiologia , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/virologia , Genoma Viral , Geografia , Dados de Sequência Molecular , Noroeste dos Estados Unidos/epidemiologia , RNA Viral/genética , Reoviridae/classificação , Infecções por Reoviridae/epidemiologia , Infecções por Reoviridae/virologia , Salmonidae/virologia , Análise de Sequência de DNA/métodos , Homologia de Sequência de AminoácidosRESUMO
Marine Havest Canada has significantly reduced its antimicrobial usage in salmon farming over the last 8 years. Change has come about largely through improvements in production, health management, and livestock selection. However, antimicrobial treatments are still required for stomatitis and bacterial kidney disease. Lack of efficacious vaccines and the limited number of licensed antimicrobials available to the industry continue to be of concern.
Tendances de l'utilisation des antimicrobiens dans la production de saumons d'élevage de Marine Harvest Canada en Colombie-Britannique (20032011). Marine Havest Canada a significativement réduit son utilisation d'antimicrobiens dans l'élevage du saumon au cours des 8 dernières années. Le changement s'est produit surtout à l'aide d'améliorations au niveau de la production, de la gestion de la santé et de la sélection des poissons d'élevage. Cependant, les traitements antimicrobiens sont toujours requis pour la stomatite et la maladie rénale bactérienne. L'absence de vaccins efficaces et le nombre limité d'antimicrobiens homologués disponibles dans l'industrie continuent de susciter des préoccupations.(Traduit par Isabelle Vallières).
