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Takano T, Miwa S, Matsuyama T, Kiryu I, Honjo M, Sakai T, Matsuura Y, Yamasaki M, Kumagai A, Nakayasu C. Clinical symptoms and histopathological changes in coho salmon affected by the erythrocytic inclusion body syndrome (EIBS) are caused by the infection of piscine orthoreovirus 2 (PRV-2). JOURNAL OF FISH DISEASES 2024; 47:e13939. [PMID: 38481093 DOI: 10.1111/jfd.13939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 02/29/2024] [Accepted: 03/01/2024] [Indexed: 05/12/2024]
Abstract
The relationship of histopathological changes and the infection of Piscine orthoreovirus 2 (PRV-2) was investigated in coho salmon that were suffering from the erythrocytic inclusion body syndrome (EIBS). Immunohistochemical observations revealed abundant σ1 protein of PRV-2 in the spongy layer of the ventricle of the heart, where severe myocarditis was observed. In the spleen, the virus protein was detected in many erythrocytes, some of which were spherical-shaped and apparently dead. The number of erythrocytes was decreased in the spleen compared to the apparently healthy fish. The virus protein was also detected in some erythrocytes in blood vessels. The viral protein was often detected in many macrophages ingesting erythrocytes or dead cell debris in the spleen or in the kidney sinusoids. Large amounts of the viral genomic segment L2 were also detected in these organs by RT-qPCR. Many necrotic foci were found in the liver, although the virus protein was not detected in the hepatocytes. These results suggest that the primary targets of PRV-2 are myocardial cells and erythrocytes and that clinical symptoms such as anaemia or jaundice and histopathological changes such as myocarditis in EIBS-affected coho salmon are caused by PRV-2 infection.
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Affiliation(s)
- Tomokazu Takano
- Pathology Division, Aquaculture Research Department, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Minami-ise, Japan
| | - Satoshi Miwa
- Pathology Division, Aquaculture Research Department, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Minami-ise, Japan
| | - Tomomasa Matsuyama
- Pathology Division, Aquaculture Research Department, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Minami-ise, Japan
| | - Ikunari Kiryu
- Pathology Division, Aquaculture Research Department, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Minami-ise, Japan
| | - Miho Honjo
- Miyagi Prefecture Fisheries Technology Institute, Ishinomaki, Japan
| | - Takamitsu Sakai
- Pathology Division, Aquaculture Research Department, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Minami-ise, Japan
| | - Yuta Matsuura
- Pathology Division, Aquaculture Research Department, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Minami-ise, Japan
| | - Masatoshi Yamasaki
- Pathology Division, Aquaculture Research Department, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Minami-ise, Japan
| | - Akira Kumagai
- Miyagi Prefecture Fisheries Technology Institute, Ishinomaki, Japan
| | - Chihaya Nakayasu
- Pathology Division, Aquaculture Research Department, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Minami-ise, Japan
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Polinski MP, Gross LA, Marty GD, Garver KA. Heart inflammation and piscine orthoreovirus genotype-1 in Pacific Canada Atlantic salmon net-pen farms: 2016-2019. BMC Vet Res 2022; 18:306. [PMID: 35948980 PMCID: PMC9364591 DOI: 10.1186/s12917-022-03409-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 07/27/2022] [Indexed: 11/25/2022] Open
Abstract
Piscine orthoreovirus genotype-1 (PRV-1) is a virus commonly associated with Atlantic salmon aquaculture with global variability in prevalence and association with disease. From August 2016 to November 2019, 2,070 fish sampled at 64 Atlantic salmon net-pen farm sites during 302 sampling events from British Columbia, Canada, were screened for PRV-1 using real-time qPCR. Nearly all populations became PRV-1 positive within one year of seawater entry irrespective of location, time of stocking, or producer. Cohorts became infected between 100–300 days at sea in > 90% of repeatedly sampled sites and remained infected until harvest (typically 500–700 days at sea). Heart inflammation, which is sometimes attributed to PRV-1, was also assessed in 779 production mortalities from 47 cohorts with known PRV status. Mild heart inflammation was common in mortalities from both PRV + and PRV- populations (67% and 68% prevalence, respectively). Moderate and severe lymphoplasmacytic heart inflammation was rare (11% and 3% prevalence, respectively); however, mainly arose (66 of 77 occurrences) in populations with PRV-1. Detection of PRV-1 RNA was also accomplished in water and sediment for which methods are described. These data cumulatively identify that PRV-1 ubiquitously infects farmed Atlantic salmon in British Columbia during seawater production but only in rare instances correlates with heart inflammation.
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Affiliation(s)
- Mark P Polinski
- Fisheries and Oceans, Canada Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, V9T6N7, Canada. .,U.S. Department of Agriculture National Coldwater Marine Aquaculture Center, Portage Rd, Orono, ME, 04469, USA.
| | - Lynden A Gross
- Fisheries and Oceans, Canada Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, V9T6N7, Canada
| | - Gary D Marty
- Animal Health Centre, Ministry of Agriculture and Food, 1767 Angus Campbell Rd, Abbotsford, V3G2M3, Canada
| | - Kyle A Garver
- Fisheries and Oceans, Canada Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, V9T6N7, Canada
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3
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Meyers TR, Hickey N. A Perspective: Molecular Detections of New Agents in Finfish-Interpreting Biological Significance for Fish Health Management. JOURNAL OF AQUATIC ANIMAL HEALTH 2022; 34:47-57. [PMID: 35384072 DOI: 10.1002/aah.10155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 12/31/2021] [Accepted: 03/31/2022] [Indexed: 06/14/2023]
Abstract
The increased sensitivity of advanced molecular techniques greatly exceeds the sensitivities of traditional detection methods for infectious agents. This sensitivity causes difficulty in interpreting the biological significance of such detections in fish (and shellfish), especially when the agent(s) cannot be cultured in the laboratory. In the Pacific Northwest, including Canada and Alaska, molecular detections of "new" (unknown or known but discovered in a different geographic location or fish host) potentially infectious agents in fish have received extensive media attention and misinterpretation that call for resource agencies to change current fish health surveillance practices or policies to include these agents. Fish health specialists from several of these agencies and organizations (see Acknowledgments) advise that any policy changes should be made only after further investigations to avoid wasting resources to conduct surveillance for organisms that are not significant to fish health or for noninfectious genetic material that does not represent a viable agent. Molecular detection is not proof of agent viability within or on host tissues and requires further investigation regarding the agent's ability to replicate and evidence that the agent causes substantial risk of disease to exposed fish populations. This document provides examples of molecularly detected agents causing public concern that were accompanied by little or no data to provide context and assessment of biological significance, highlights important questions to be answered regarding these detections, and provides a suggested pathway of investigative criteria to determine viability and pathogenicity of such agents that are necessary for consideration of any changes to aquatic animal health practices and policies.
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Affiliation(s)
- Theodore R Meyers
- Alaska Department of Fish and Game, Commercial Fisheries Division, Post Office Box 115526, Juneau, Alaska, 99811, USA
| | - Nora Hickey
- Northwest Indian Fisheries Commission, 6730 Martin Way East, Olympia, Washington, 98516, USA
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Zhao J, Vendramin N, Cuenca A, Polinski M, Hawley LM, Garver KA. Pan-Piscine Orthoreovirus (PRV) Detection Using Reverse Transcription Quantitative PCR. Pathogens 2021; 10:pathogens10121548. [PMID: 34959503 PMCID: PMC8707331 DOI: 10.3390/pathogens10121548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/22/2021] [Accepted: 11/25/2021] [Indexed: 11/16/2022] Open
Abstract
Piscine orthoreovirus (PRV) infects farmed and wild salmon and trout species in North America, South America, Europe, and East Asia. PRV groups into three distinct genotypes (PRV-1, PRV-2, and PRV-3) that can vary in distribution, host specificity, and/or disease potential. Detection of the virus is currently restricted to genotype specific assays such that surveillance programs require the use of three assays to ensure universal detection of PRV. Consequently, herein, we developed, optimized, and validated a real-time reverse transcription quantitative PCR assay (RT-qPCR) that can detect all known PRV genotypes with high sensitivity and specificity. Targeting a conserved region at the 5′ terminus of the M2 segment, the pan-PRV assay reliably detected all PRV genotypes with as few as five copies of RNA. The assay exclusively amplifies PRV and does not cross-react with other salmonid viruses or salmonid host genomes and can be performed as either a one- or two-step RT-qPCR. The assay is highly reproducible and robust, showing 100% agreement in test results from an inter-laboratory comparison between two laboratories in two countries. Overall, as the assay provides a single test to achieve highly sensitive pan-specific PRV detection, it is suitable for research, diagnostic, and surveillance purposes.
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Affiliation(s)
- Julie Zhao
- Pacific Biological Station, Department of Fisheries and Oceans, Nanaimo, BC V9T 6N7, Canada; (J.Z.); (M.P.); (L.M.H.)
| | - Niccolò Vendramin
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, 2800 Lyngby-Taarbæk, Denmark; (N.V.); (A.C.)
| | - Argelia Cuenca
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, 2800 Lyngby-Taarbæk, Denmark; (N.V.); (A.C.)
| | - Mark Polinski
- Pacific Biological Station, Department of Fisheries and Oceans, Nanaimo, BC V9T 6N7, Canada; (J.Z.); (M.P.); (L.M.H.)
| | - Laura M. Hawley
- Pacific Biological Station, Department of Fisheries and Oceans, Nanaimo, BC V9T 6N7, Canada; (J.Z.); (M.P.); (L.M.H.)
| | - Kyle A. Garver
- Pacific Biological Station, Department of Fisheries and Oceans, Nanaimo, BC V9T 6N7, Canada; (J.Z.); (M.P.); (L.M.H.)
- Correspondence:
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Polinski MP, Zhang Y, Morrison PR, Marty GD, Brauner CJ, Farrell AP, Garver KA. Innate antiviral defense demonstrates high energetic efficiency in a bony fish. BMC Biol 2021; 19:138. [PMID: 34253202 PMCID: PMC8276435 DOI: 10.1186/s12915-021-01069-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 06/09/2021] [Indexed: 11/18/2022] Open
Abstract
Background Viruses can impose energetic demands on organisms they infect, in part by hosts mounting resistance. Recognizing that oxygen uptake reliably indicates steady-state energy consumption in all vertebrates, we comprehensively evaluated oxygen uptake and select transcriptomic messaging in sockeye salmon challenged with either a virulent rhabdovirus (IHNV) or a low-virulent reovirus (PRV). We tested three hypotheses relating to the energetic costs of viral resistance and tolerance in this vertebrate system: (1) mounting resistance incurs a metabolic cost or limitation, (2) induction of the innate antiviral interferon system compromises homeostasis, and (3) antiviral defenses are weakened by acute stress. Results IHNV infections either produced mortality within 1–4 weeks or the survivors cleared infections within 1–9 weeks. Transcription of three interferon-stimulated genes (ISGs) was strongly correlated with IHNV load but not respiratory performance. Instead, early IHNV resistance was associated with a mean 19% (95% CI = 7–31%; p = 0.003) reduction in standard metabolic rate. The stress of exhaustive exercise did not increase IHNV transcript loads, but elevated host inflammatory transcriptional signaling up to sevenfold. For PRV, sockeye tolerated high-load systemic PRV blood infections. ISG transcription was transiently induced at peak PRV loads without associated morbidity, microscopic lesions, or major changes in aerobic or anaerobic respiratory performance, but some individuals with high-load blood infections experienced a transient, minor reduction in hemoglobin concentration and increased duration of excess post-exercise oxygen consumption. Conclusions Contrary to our first hypothesis, effective resistance against life-threatening rhabdovirus infections or tolerance to high-load reovirus infections incurred minimal metabolic costs to salmon. Even robust systemic activation of the interferon system did not levy an allostatic load sufficient to compromise host homeostasis or respiratory performance, rejecting our second hypothesis that this ancient innate vertebrate antiviral defense is itself energetically expensive. Lastly, an acute stress experienced during testing did not weaken host antiviral defenses sufficiently to promote viral replication; however, a possibility for disease intensification contingent upon underlying inflammation was indicated. These data cumulatively demonstrate that fundamental innate vertebrate defense strategies against potentially life-threatening viral exposure impose limited putative costs on concurrent aerobic or energetic demands of the organism. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01069-2.
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Affiliation(s)
- Mark P Polinski
- Fisheries and Oceans Canada Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, V9T6N7, Canada.
| | - Yangfan Zhang
- Faculty of Land and Food Systems, University of British Columbia, MCML 344-2357 Main Mall, Vancouver, V6T1Z4, Canada
| | - Phillip R Morrison
- Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, V6T1Z4, Canada
| | - Gary D Marty
- Animal Health Centre, Ministry of Agriculture, Food and Fisheries, 1767 Angus Campbell Rd, Abbotsford, V3G2M3, Canada
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, V6T1Z4, Canada
| | - Anthony P Farrell
- Faculty of Land and Food Systems, University of British Columbia, MCML 344-2357 Main Mall, Vancouver, V6T1Z4, Canada.,Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, V6T1Z4, Canada
| | - Kyle A Garver
- Fisheries and Oceans Canada Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, V9T6N7, Canada.
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Mordecai GJ, Miller KM, Bass AL, Bateman AW, Teffer AK, Caleta JM, Di Cicco E, Schulze AD, Kaukinen KH, Li S, Tabata A, Jones BR, Ming TJ, Joy JB. Aquaculture mediates global transmission of a viral pathogen to wild salmon. SCIENCE ADVANCES 2021; 7:7/22/eabe2592. [PMID: 34039598 PMCID: PMC8153721 DOI: 10.1126/sciadv.abe2592] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 04/07/2021] [Indexed: 05/07/2023]
Abstract
Global expansion of aquaculture and agriculture facilitates disease emergence and catalyzes transmission to sympatric wildlife populations. The health of wild salmon stocks critically concerns Indigenous peoples, commercial and recreational fishers, and the general public. Despite potential impact of viral pathogens such as Piscine orthoreovirus-1 (PRV-1) on endangered wild salmon populations, their epidemiology in wild fish populations remains obscure, as does the role of aquaculture in global and local spread. Our phylogeographic analyses of PRV-1 suggest that development of Atlantic salmon aquaculture facilitated spread from Europe to the North and South East Pacific. Phylogenetic analysis and reverse transcription polymerase chain reaction surveillance further illuminate the circumstances of emergence of PRV-1 in the North East Pacific and provide strong evidence for Atlantic salmon aquaculture as a source of infection in wild Pacific salmon. PRV-1 is now an important infectious agent in critically endangered wild Pacific salmon populations, fueled by aquacultural transmission.
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Affiliation(s)
- Gideon J Mordecai
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada.
| | - Kristina M Miller
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada.
- Department of Forest and Conservation Sciences, Forest Sciences Centre, 3041 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Arthur L Bass
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Andrew W Bateman
- Pacific Salmon Foundation, 1682 W 7th Ave., Vancouver, BC V6J 4S6, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Room 3055, Toronto, ON M5S 3B2, Canada
- Salmon Coast Field Station General Delivery, Simoom Sound, BC V0P 1S0, Canada
| | - Amy K Teffer
- David H. Smith Conservation Research Fellowship, Society for Conservation Biology, Washington, DC, USA
| | - Jessica M Caleta
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Emiliano Di Cicco
- Pacific Salmon Foundation, 1682 W 7th Ave., Vancouver, BC V6J 4S6, Canada
| | - Angela D Schulze
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Karia H Kaukinen
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Shaorong Li
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Amy Tabata
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Brad R Jones
- BC Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada
- Bioinformatics Programme, University of British Columbia, Vancouver, BC, Canada
| | - Tobi J Ming
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Jeffrey B Joy
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
- BC Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada
- Bioinformatics Programme, University of British Columbia, Vancouver, BC, Canada
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Extensive Phylogenetic Analysis of Piscine Orthoreovirus Genomic Sequences Shows the Robustness of Subgenotype Classification. Pathogens 2021; 10:pathogens10010041. [PMID: 33430212 PMCID: PMC7825714 DOI: 10.3390/pathogens10010041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 11/17/2022] Open
Abstract
Piscine orthoreovirus (PRV) belongs to the family Reoviridae and has been described mainly in association with salmonid infections. The genome of PRV consists of about 23,600 bp, with 10 segments of double-stranded RNA, classified as small (S1 to S4), medium (M1, M2 and M3) and large (L1, L2 and L3); these range approximately from 1000 bp (segment S4) to 4000 bp (segment L1). How the genetic variation among PRV strains affects the virulence for salmonids is still poorly understood. The aim of this study was to describe the molecular phylogeny of PRV based on an extensive sequence analysis of the S1 and M2 segments of PRV available in the GenBank database to date (May 2020). The analysis was extended to include new PRV sequences for S1 and M2 segments. In addition, subgenotype classifications were assigned to previously published unclassified sequences. It was concluded that the phylogenetic trees are consistent with the original classification using the PRV genomic segment S1, which differentiates PRV into two major genotypes, I and II, and each of these into two subgenotypes, designated as Ia and Ib, and IIa and IIb, respectively. Moreover, some clusters of country- and host-specific PRV subgenotypes were observed in the subset of sequences used. This work strengthens the subgenotype classification of PRV based on the S1 segment and can be used to enhance research on the virulence of PRV.
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8
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Polinski MP, Vendramin N, Cuenca A, Garver KA. Piscine orthoreovirus: Biology and distribution in farmed and wild fish. JOURNAL OF FISH DISEASES 2020; 43:1331-1352. [PMID: 32935367 DOI: 10.1111/jfd.13228] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/06/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
Piscine orthoreovirus (PRV) is a common and widely distributed virus of salmonids. Since its discovery in 2010, the virus has been detected in wild and farmed stocks from North America, South America, Europe and East Asia in both fresh and salt water environments. Phylogenetic analysis suggests three distinct genogroups of PRV with generally discrete host tropisms and/or regional patterns. PRV-1 is found mainly in Atlantic (Salmo salar), Chinook (Oncorhynchus tshawytscha) and Coho (Oncorhynchus kisutch) Salmon of Europe and the Americas; PRV-2 has only been detected in Coho Salmon of Japan; and PRV-3 has been reported primarily in Rainbow Trout (Oncorhynchus mykiss) in Europe. All three genotypes can establish high-load systemic infections by targeting red blood cells for principal replication. Each genotype has also demonstrated potential to cause circulatory disease. At the same time, high-load PRV infections occur in non-diseased salmon and trout, indicating a complexity for defining PRV's role in disease aetiology. Here, we summarize the current body of knowledge regarding PRV following 10 years of study.
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Affiliation(s)
- Mark P Polinski
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Niccoló Vendramin
- National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark
| | - Argelia Cuenca
- National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark
| | - Kyle A Garver
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
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9
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Emergence and Spread of Piscine orthoreovirus Genotype 3. Pathogens 2020; 9:pathogens9100823. [PMID: 33036449 PMCID: PMC7601675 DOI: 10.3390/pathogens9100823] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/29/2020] [Accepted: 10/02/2020] [Indexed: 02/07/2023] Open
Abstract
Piscine orthoreovirus (PRV) is a relevant pathogen for salmonid aquaculture worldwide. In 2015, a new genotype of PRV (genotype 3, PRV-3) was discovered in Norway, and in 2017 PRV-3 was detected for first time in Denmark in association with complex disease cases in rainbow trout in recirculating aquaculture systems (RAS). To explore the epidemiology of PRV-3 in Denmark, a surveillance study was conducted in 2017 to 2019. Fifty-three farms, including both flow through and RAS, were screened for PRV-3. Of the farms examined, PRV-3 was detected in thirty-eight (71.7%), with the highest prevalence in grow-out farms. Notably, in Denmark disease outbreaks were only observed in RAS. Additionally, wild Atlantic salmon and brown trout populations were included in the screening, and PRV-3 was not detected in the three years where samples were obtained (2016, 2018, and 2019). Historical samples in the form of archived material at the Danish National Reference Laboratory for Fish Diseases were also tested for the presence of PRV-3, allowing us to establish that the virus has been present in Denmark at least since 1995. Sequence analyses of segment S1 and M2, as well as full genome analyses of selected isolates, did not reveal clear association between genetic makeup in these two segments and virulence in the form of disease outbreaks in the field.
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Schmidt-Posthaus H, Koch M, Seuberlich T, Birrer C, Hirschi R, Kugler M. Mysterious syndrome causing high mortality in wild brown trout in Eastern Switzerland, pathology and search for a possible cause. JOURNAL OF FISH DISEASES 2020; 43:1317-1324. [PMID: 32830324 DOI: 10.1111/jfd.13241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 06/11/2023]
Abstract
Since 2016, annually occurring species-specific die-offs of brown trout (Salmo trutta fario) occurred in the Thur River, situated in the Eastern part of Switzerland. These events lead to drastically reduced population densities in the impacted river regions. Clinical signs in brown trout and mortality were restricted to few weeks in August/September. To characterize the syndrome and to find possible causes, from end of March to November 2018, one-year-old brown trout (Salmo trutta fario) and rainbow trout (Oncorhynchus mykiss) were exposed to water from Thur River, fish were sampled regularly and screened for infectious agents, including viral metagenomics, and pathology was described. Starting approximately four months post-exposure, brown trout showed severe lymphohistiocytic pancarditis and necrotizing and haemorrhagic hepatitis. These lesions were recorded until the end of the experiment in November. Rainbow trout were not affected at any point in time. No infectious agents could be identified so far as cause of disease, especially no viral aetiology. Even if pathogenesis and pathology point in the direction of an infectious agent, a causative relationship could not be confirmed and aetiology remains unclear.
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Affiliation(s)
- Heike Schmidt-Posthaus
- Centre for Fish and Wildlife Health, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University Bern, Bern, Switzerland
| | - Michel Koch
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University Bern, Bern, Switzerland
| | - Torsten Seuberlich
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University Bern, Bern, Switzerland
| | - Christoph Birrer
- Canton St. Gallen, Department of Economic Affairs, Office for Nature, Hunting and Fisheries, St. Gallen, Switzerland
| | - Regula Hirschi
- Centre for Fish and Wildlife Health, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University Bern, Bern, Switzerland
| | - Michael Kugler
- Canton St. Gallen, Department of Economic Affairs, Office for Nature, Hunting and Fisheries, St. Gallen, Switzerland
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11
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Marty GD, Bidulka J, Joseph T. Cross-sectional study of histopathology and piscine orthoreovirus during a marine production cycle of farmed Atlantic salmon (Salmo salar L.) in British Columbia, Canada. JOURNAL OF FISH DISEASES 2020; 43:1019-1028. [PMID: 33448429 DOI: 10.1111/jfd.13210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/30/2020] [Accepted: 06/01/2020] [Indexed: 06/12/2023]
Abstract
Two cohorts of farmed Atlantic salmon, Salmo salar L., in British Columbia, Canada, were sampled for histopathology (nine organs) and piscine orthoreovirus (PRV-1) PCR after seawater entry at 2, 4, 6, 8, 10, 13, 16 and 19 months (20 fish per cohort per date). One cohort-from a PRV+ hatchery-remained PRV+ throughout the study (sample prevalence 80%-100%). In an adjacent pen, the other cohort-from a PRV- hatchery-was 0% PRV+ at 78 days, 30% PRV+ at 128 days and ≥95% PRV+ thereafter. Among sample cohorts that were ≥80% PRV+, median Ct values were nominally less among fish sourced from the PRV- hatchery (28.7-33.3) than the PRV+ hatchery (30.8-35.2). No microscopic lesions were associated with PRV Ct value (minimum = 25.6). About 3% of fish in both cohorts had moderate inflammatory heart lesions; among these fish, only one had skeletal muscle inflammation (mild), and PRV Ct values were similar to unaffected cohorts sampled the same day. Also, among 16 moribund or freshly dead fish sampled opportunistically during the study, 14 were PRV+, and none had significant inflammatory heart lesions. These data support the hypothesis that British Columbia PRV-1 does not contribute to mortality.
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Affiliation(s)
- Gary D Marty
- Animal Health Centre, Ministry of Agriculture, Abbotsford, BC, Canada
| | - Julie Bidulka
- Animal Health Centre, Ministry of Agriculture, Abbotsford, BC, Canada
| | - Tomy Joseph
- Animal Health Centre, Ministry of Agriculture, Abbotsford, BC, Canada
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12
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Wessel Ø, Hansen EF, Løvoll M, Inami M, Husby A, Kruse G, Dahle MK, Rimstad E. Inactivation of Piscine orthoreovirus. JOURNAL OF FISH DISEASES 2020; 43:1039-1048. [PMID: 32632958 DOI: 10.1111/jfd.13214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 06/11/2023]
Abstract
Piscine orthoreovirus infects various salmonid fish species, and the infection is associated with diseases such as heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). There are no vaccines available or genetically selected resistant hosts that can efficiently control piscine orthoreovirus (PRV) infection. Currently, the only prophylactic measure against PRV is general biosecurity measures aiming to break the transmission cycle. Methods to eradicate infectious virus from contaminated facilities are desirable, but the knowledge on how to inactivate PRV is lacking. A major bottleneck for inactivation studies is the lack of ability to propagate PRV in cell culture. Therefore, in this study we developed an in vivo model for detection of infectious PRV particles after treatment of the virus with inactivation tools such as heat, pH, iodine, UV and commercially available disinfectants. The results show that standard iodine treatment is efficient in inactivation of the virus, and similarly are high and low pH extremes and treatment with Virocid, a commercially available disinfectant. A UV dose of at least 50 mJ/cm2 is required for inactivation, and the virus has high resistance against heat treatment.
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Affiliation(s)
- Øystein Wessel
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Elisabeth F Hansen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | | | | | | | | | | | - Espen Rimstad
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
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13
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Siah A, Knutsen E, Richmond Z, Mills M, Frisch K, Powell JFF, Brevik Ø, Duesund H. Real-time RT-qPCR assay to detect sequences in the Piscine orthoreovirus-1 genome segment S1 associated with heart and skeletal muscle inflammation in Atlantic salmon. JOURNAL OF FISH DISEASES 2020; 43:955-962. [PMID: 32608050 DOI: 10.1111/jfd.13205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
During the last decade, Piscine orthoreovirus was identified as the main causative agent of heart and skeletal muscle inflammation (HSMI) in Atlantic Salmon, Norway. A recent study showed that PRV-1 sequences from salmonid collected in North Atlantic Pacific Coast (NAPC) grouped separately from the Norwegian sequences found in Atlantic Salmon diagnosed with HSMI. Currently, the routine assay used to screen for PRV-1 in NAPC water and worldwide cannot differentiate between the two groups of PRV-1. Therefore, this study aimed at developing a real-time polymerase chain reaction (RT-qPCR) assay to target the PRV-1 genome segments specific for variants associated with HSMI. The assay was optimized and tested against 71 tissue samples collected from different regions including Norway, Chile and both coast of Canada and different hosts farmed Atlantic Salmon, wild Coho Salmon and escaped Atlantic Salmon collected in British Columbia, West Coast of Canada. This assay has the potential to be used for screening salmonids and non-salmonids that may carry PRV-1 potentially causing HSMI.
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Affiliation(s)
- Ahmed Siah
- British Columbia Centre for Aquatic Health Sciences, Campbell River, BC, Canada
| | | | - Zina Richmond
- British Columbia Centre for Aquatic Health Sciences, Campbell River, BC, Canada
| | | | | | - James F F Powell
- British Columbia Centre for Aquatic Health Sciences, Campbell River, BC, Canada
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14
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Siah A, Breyta RB, Warheit KI, Gagne N, Purcell MK, Morrison D, Powell JFF, Johnson SC. Genomes reveal genetic diversity of Piscine orthoreovirus in farmed and free-ranging salmonids from Canada and USA. Virus Evol 2020; 6:veaa054. [PMID: 33381304 PMCID: PMC7751156 DOI: 10.1093/ve/veaa054] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Piscine orthoreovirus (PRV-1) is a segmented RNA virus, which is commonly found in salmonids in the Atlantic and Pacific Oceans. PRV-1 causes the heart and skeletal muscle inflammation disease in Atlantic salmon and is associated with several other disease conditions. Previous phylogenetic studies of genome segment 1 (S1) identified four main genogroups of PRV-1 (S1 genogroups I–IV). The goal of the present study was to use Bayesian phylogenetic inference to expand our understanding of the spatial, temporal, and host patterns of PRV-1 from the waters of the northeast Pacific. To that end, we determined the coding genome sequences of fourteen PRV-1 samples that were selected to improve our knowledge of genetic diversity across a broader temporal, geographic, and host range, including the first reported genome sequences from the northwest Atlantic (Eastern Canada). Nucleotide and amino acid sequences of the concatenated genomes and their individual segments revealed that established sequences from the northeast Pacific were monophyletic in all analyses. Bayesian inference phylogenetic trees of S1 sequences using BEAST and MrBayes also found that sequences from the northeast Pacific grouped separately from sequences from other areas. One PRV-1 sample (WCAN_BC17_AS_2017) from an escaped Atlantic salmon, collected in British Columbia but derived from Icelandic broodstock, grouped with other S1 sequences from Iceland. Our concatenated genome and S1 analysis demonstrated that PRV-1 from the northeast Pacific is genetically distinct but descended from PRV-1 from the North Atlantic. However, the analyses were inconclusive as to the timing and exact source of introduction into the northeast Pacific, either from eastern North America or from European waters of the North Atlantic. There was no evidence that PRV-1 was evolving differently between free-ranging Pacific Salmon and farmed Atlantic Salmon. The northeast Pacific PRV-1 sequences fall within genogroup II based on the classification of Garseth, Ekrem, and Biering (Garseth, A. H., Ekrem, T., and Biering, E. (2013) ‘Phylogenetic Evidence of Long Distance Dispersal and Transmission of Piscine Reovirus (PRV) between Farmed and Wild Atlantic Salmon’, PLoS One, 8: e82202.), which also includes North Atlantic sequences from Eastern Canada, Iceland, and Norway. The additional full-genome sequences herein strengthen our understanding of phylogeographical patterns related to the northeast Pacific, but a more balanced representation of full PRV-1 genomes from across its range, as well additional sequencing of archived samples, is still needed to better understand global relationships including potential transmission links among regions.
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Affiliation(s)
- A Siah
- British Columbia Centre for Aquatic Health Sciences, 871A Island Highway, V9W 2C2, Campbell River, BC, Canada
| | - R B Breyta
- School of Aquatic Fisheries Sciences, University of Washington, Western Fisheries Research Center, USGS, 6505 NE 65th Street Seattle, WA 98115-5016, USA
| | - K I Warheit
- Washington Department of Fish and Wildlife PO Box 43200, Olympia, WA 98504-3200, USA
| | - N Gagne
- Gulf Fisheries Center, Fisheries & Oceans, 343 Université Ave, Moncton, NB E1C 5K4, Canada
| | - M K Purcell
- Western Fisheries Research Center, U.S. Geological Survey, 56505 NE 65th Street Seattle, WA 98115-5016, USA
| | - D Morrison
- Mowi Canada West, Campbell River, BC, Canada
| | - J F F Powell
- British Columbia Centre for Aquatic Health Sciences, 871A Island Highway, V9W 2C2, Campbell River, BC, Canada
| | - S C Johnson
- Fisheries & Oceans Canada, Nanaimo, British Columbia, Canada
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15
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Purcell MK, Powers RL, Taksdal T, McKenney D, Conway CM, Elliott DG, Polinski M, Garver K, Winton J. Consequences of Piscine orthoreovirus genotype 1 (PRV-1) infections in Chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch) and rainbow trout (O. mykiss). JOURNAL OF FISH DISEASES 2020; 43:719-728. [PMID: 32476167 PMCID: PMC7384080 DOI: 10.1111/jfd.13182] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/03/2020] [Accepted: 02/05/2020] [Indexed: 05/02/2023]
Abstract
Piscine orthoreovirus genotype 1 (PRV-1) is the causative agent of heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar L.). The virus has also been found in Pacific salmonids in western North America, raising concerns about the risk to native salmon and trout. Here, we report the results of laboratory challenges using juvenile Chinook salmon, coho salmon and rainbow trout injected with tissue homogenates from Atlantic salmon testing positive for PRV-1 or with control material. Fish were sampled at intervals to assess viral RNA transcript levels, haematocrit, erythrocytic inclusions and histopathology. While PRV-1 replicated in all species, there was negligible mortality in any group. We observed a few erythrocytic inclusion bodies in fish from the PRV-1-infected groups. At a few time points, haematocrits were significantly lower in the PRV-1-infected groups relative to controls, but in no case was anaemia noted. The most common histopathological finding was mild, focal myocarditis in both the non-infected controls and PRV-1-infected fish. All cardiac lesions were judged mild, and none were consistent with those of HSMI. Together, these results suggest all three species are susceptible to PRV-1 infection, but in no case did infection cause notable disease in these experiments.
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Affiliation(s)
| | - Rachel L. Powers
- U.S. Geological SurveyWestern Fisheries Research CenterSeattleWAUSA
| | | | - Doug McKenney
- School of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWAUSA
| | - Carla M. Conway
- U.S. Geological SurveyWestern Fisheries Research CenterSeattleWAUSA
| | - Diane G. Elliott
- U.S. Geological SurveyWestern Fisheries Research CenterSeattleWAUSA
| | - Mark Polinski
- Pacific Biological Station, Fisheries and Oceans CanadaNanaimoBCCanada
| | - Kyle Garver
- Pacific Biological Station, Fisheries and Oceans CanadaNanaimoBCCanada
| | - James Winton
- U.S. Geological SurveyWestern Fisheries Research CenterSeattleWAUSA
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16
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Jia B, Delphino MKVC, Awosile B, Hewison T, Whittaker P, Morrison D, Kamaitis M, Siah A, Milligan B, Johnson SC, Gardner IA. Review of infectious agent occurrence in wild salmonids in British Columbia, Canada. JOURNAL OF FISH DISEASES 2020; 43:153-175. [PMID: 31742733 DOI: 10.1111/jfd.13084] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/22/2019] [Accepted: 08/26/2019] [Indexed: 06/10/2023]
Abstract
Wild Pacific salmonids (WPS) are economically and culturally important to the Pacific North region. Most recently, some populations of WPS have been in decline. Of hypothesized factors contributing to the decline, infectious agents have been postulated to increase the risk of mortality in Pacific salmon. We present a literature review of both published journal and unpublished data to describe the distribution of infectious agents reported in wild Pacific salmonid populations in British Columbia (BC), Canada. We targeted 10 infectious agents, considered to potentially cause severe economic losses in Atlantic salmon or be of conservation concern for wild salmon in BC. The findings indicated a low frequency of infectious hematopoietic necrosis virus, piscine orthoreovirus, viral haemorrhagic septicaemia virus, Aeromonas salmonicida, Renibacterium salmoninarum, Piscirickettsia salmonis and other Rickettsia-like organisms, Yersinia ruckeri, Tenacibaculum maritimum and Moritella viscosa. No positive results were reported for infestations with Paramoeba perurans in peer-reviewed papers and the DFO Fish Pathology Program database. This review synthesizes existing information, as well as gaps therein, that can support the design and implementation of a long-term surveillance programme of infectious agents in wild salmonids in BC.
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Affiliation(s)
- Beibei Jia
- Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Marina K V C Delphino
- Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Babafela Awosile
- Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Tim Hewison
- Grieg Seafood BC Ltd., Campbell River, BC, Canada
| | | | | | | | - Ahmed Siah
- British Columbia Centre for Aquatic Health Sciences, Campbell River, BC, Canada
| | | | - Stewart C Johnson
- Pacific Biological Station, Fisheries and Oceans Canada (DFO), Nanaimo, BC, Canada
| | - Ian A Gardner
- Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
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17
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Vendramin N, Cuenca A, Sørensen J, Alencar ALF, Christiansen DH, Jacobsen JA, Axen C, Lieffrig F, Ruane NM, Martin P, Sheehan T, Iburg TM, Rimstad E, Olesen NJ. Presence and genetic variability of Piscine orthoreovirus genotype 1 (PRV-1) in wild salmonids in Northern Europe and North Atlantic Ocean. JOURNAL OF FISH DISEASES 2019; 42:1107-1118. [PMID: 31140193 DOI: 10.1111/jfd.13025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 04/11/2019] [Accepted: 04/14/2019] [Indexed: 06/09/2023]
Abstract
Piscine orthoreovirus genotype 1 (PRV-1) is widespread in farmed Atlantic salmon (Salmo salar L.) populations in northern Europe, Canada and Chile. PRV-1 occurs in wild fish in Norway and Canada; however, little information of its geographical distribution in wild populations is currently available, and the effect of PRV-1 infection in wild populations is currently unknown. In this study, we present the findings of a survey conducted on 1,130 wild salmonids sampled in Denmark, Sweden, Ireland, Faroe Islands, France, Belgium and Greenland between 2008 and 2017. PRV-1 is reported for the first time in wild salmonids in Denmark, Sweden, Faroe Island and Ireland. The annual PRV-1 prevalence ranged from 0% in France, Belgium and Greenland to 43% in Faroe Islands. In total, 66 samples tested positive for PRV-1, including Atlantic salmon broodfish returning to spawn and Atlantic salmon collected at the feeding ground north of Faroe Islands. The phylogenetic analysis of S1 sequences of the PRV-1 isolates obtained in this survey did not show systematic geographical distribution. This study sheds light on the spread and genetic diversity of the virus identified in populations of free-living fish and provides rationale for screening wild broodfish used in restocking programmes.
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Affiliation(s)
- Niccoló Vendramin
- National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark
| | - Argelia Cuenca
- National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark
| | - Juliane Sørensen
- National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark
| | - Anna L F Alencar
- National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark
| | - Debes H Christiansen
- National Reference Laboratory for fish diseases, Faroese Food and Veterinary Authority (FFVA), Torshavn, Faroe Islands
| | - Jan A Jacobsen
- Havstovan Faroe Marine Research Institute (FAMRI), Torshavn, Faroe Islands
| | - Charlotte Axen
- Swedish National Veterinary Institute (SVA), Uppsala, Sweden
| | | | - Neil M Ruane
- Fish Health Unit, Marine Institute, Galway, Ireland
| | | | - Timothy Sheehan
- Northeast Fisheries Science Center, National Marine Fisheries Service, Woods Hole, Massachusetts
| | - Tine M Iburg
- National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark
| | | | - Niels J Olesen
- National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark
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18
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Evolution of the Piscine orthoreovirus Genome Linked to Emergence of Heart and Skeletal Muscle Inflammation in Farmed Atlantic Salmon ( Salmo salar). Viruses 2019; 11:v11050465. [PMID: 31121920 PMCID: PMC6563308 DOI: 10.3390/v11050465] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/16/2019] [Accepted: 05/20/2019] [Indexed: 01/09/2023] Open
Abstract
Heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar) was first diagnosed in Norway in 1999. The disease is caused by Piscine orthoreovirus-1 (PRV-1). The virus is prevalent in farmed Atlantic salmon, but not always associated with disease. Phylogeny and sequence analyses of 31 PRV-1 genomes collected over a 30-year period from fish with or without HSMI, grouped the viral sequences into two main monophylogenetic clusters, one associated with HSMI and the other with low virulent PRV-1 isolates. A PRV-1 strain from Norway sampled in 1988, a decade before the emergence of HSMI, grouped with the low virulent HSMI cluster. The two distinct monophylogenetic clusters were particularly evident for segments S1 and M2. Only a limited number of amino acids were unique to the association with HSMI, and they all located to S1 and M2 encoded proteins. The observed co-evolution of the S1-M2 pair coincided in time with the emergence of HSMI in Norway, and may have evolved through accumulation of mutations and/or segment reassortment. Sequences of S1-M2 suggest selection of the HSMI associated pair, and that this segment pair has remained almost unchanged in Norwegian salmon aquaculture since 1997. PRV-1 strains from the North American Pacific Coast and Faroe Islands have not undergone this evolution, and are more closely related to the PRV-1 precursor strains not associated with clinical HSMI.
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19
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Thakur KK, Vanderstichel R, Kaukinen K, Nekouei O, Laurin E, Miller KM. Infectious agent detections in archived Sockeye salmon (Oncorhynchus nerka) samples from British Columbia, Canada (1985-94). JOURNAL OF FISH DISEASES 2019; 42:533-547. [PMID: 30742305 DOI: 10.1111/jfd.12951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 12/05/2018] [Accepted: 12/06/2018] [Indexed: 05/06/2023]
Abstract
In response to concerns that novel infectious agents were introduced through the movement of eggs as Atlantic salmon aquaculture developed in British Columbia (BC), Canada, we estimated the prevalence of infectious agents in archived return-migrating Sockeye salmon, from before and during aquaculture expansion in BC (1985-94). Of 45 infectious agents assessed through molecular assays in 652 samples, 23 (7 bacterial, 2 viral and 14 parasitic) were detected in liver tissue from six regions in BC. Prevalence ranged from 0.005 to 0.83 and varied significantly by region and year. Agent diversity ranged from 0 to 12 per fish (median 4), with the lowest diversity observed in fish from the Trans-Boundary and Central Coast regions. Agents known to be endemic in Sockeye salmon in BC, including Flavobacterium psychrophilum, Infectious haematopoietic necrosis virus, Ceratonova shasta and Parvicapsula minibicornis, were commonly observed. Others, such as Kudoa thyrsites and Piscirikettsia salmonis, were also detected. Surprisingly, infectious agents described only recently in BC salmon, Ca. Branchiomonas cysticola, Parvicapsula pseudobranchicola and Paranucleospora theridion, were also detected, indicating their potential presence prior to the expansion of the aquaculture industry. In general, our data suggest that agent distributions may not have substantially changed because of the salmon aquaculture industry.
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Affiliation(s)
- Krishna K Thakur
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Raphaël Vanderstichel
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Karia Kaukinen
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | - Omid Nekouei
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Emilie Laurin
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Kristina M Miller
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
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20
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Polinski MP, Marty GD, Snyman HN, Garver KA. Piscine orthoreovirus demonstrates high infectivity but low virulence in Atlantic salmon of Pacific Canada. Sci Rep 2019; 9:3297. [PMID: 30867461 PMCID: PMC6416343 DOI: 10.1038/s41598-019-40025-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 02/04/2019] [Indexed: 02/05/2023] Open
Abstract
Piscine orthoreovirus (PRV) is ubiquitous in farmed Atlantic salmon and sometimes associated with disease - most notably, Heart and Skeletal Muscle Inflammation (HSMI). However, PRV is also widespread in non-diseased fish, particularly in Pacific Canada, where few cases of severe heart inflammation have been documented. To better understand the mechanisms behind PRV-associated disease, this study investigated the infection dynamics of PRV from Pacific Canada and the potential for experimental passage of putatively associated heart inflammation in Pacific-adapted Mowi-McConnell Atlantic salmon. Regardless of the PRV source (fish with or without HSMI-like heart inflammation), infections led to high-load viremia that induced only minor focal heart inflammation without significant transcriptional induction of inflammatory cytokines. Repeated screening of PRV dsRNA/ssRNA along with histopathology and gene expression analysis of host blood and heart tissues identified three distinct phases of infection: (1) early systemic dissemination and replication without host recognition; (2) peak replication, erythrocyte inclusion body formation and load-dependent host recognition; (3) long-term, high-load viral persistence with limited replication or host recognition sometimes accompanied by minor heart inflammation. These findings contrast previous challenge trials with PRV from Norway that induced severe heart inflammation and indicate that strain and/or host specific factors are necessary to initiate PRV-associated disease.
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Affiliation(s)
- Mark P Polinski
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, V9T 6N7, Canada.
| | - Gary D Marty
- Animal Health Centre, Ministry of Agriculture, Abbotsford, V3G 2M3, Canada
| | - Heindrich N Snyman
- Animal Health Centre, Ministry of Agriculture, Abbotsford, V3G 2M3, Canada
| | - Kyle A Garver
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, V9T 6N7, Canada
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21
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Zhang Y, Polinski MP, Morrison PR, Brauner CJ, Farrell AP, Garver KA. High-Load Reovirus Infections Do Not Imply Physiological Impairment in Salmon. Front Physiol 2019; 10:114. [PMID: 30930782 PMCID: PMC6425399 DOI: 10.3389/fphys.2019.00114] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 01/30/2019] [Indexed: 12/14/2022] Open
Abstract
The recent ubiquitous detection of PRV among salmonids has sparked international concern about the cardiorespiratory performance of infected wild and farmed salmon. Piscine orthoreovirus (PRV) has been shown to create substantial viremia in salmon by targeting erythrocytes for principle replication. In some instances, infections develop into heart and skeletal muscle inflammation (HSMI) or other pathological conditions affecting the respiratory system. Critical to assessing the seriousness of PRV infections are controlled infection studies that measure physiological impairment to critical life support systems. Respiratory performance is such a system and here multiple indices were measured to test the hypothesis that a low-virulence strain of PRV from Pacific Canada compromises the cardiorespiratory capabilities of Atlantic salmon. Contrary to this hypothesis, the oxygen affinity and carrying capacity of erythrocytes were unaffected by PRV despite the presence of severe viremia, minor heart pathology and transient cellular activation of antiviral response pathways. Similarly, PRV-infected fish had neither sustained nor appreciable differences in respiratory capabilities compared with control fish. The lack of functional harm to salmon infected with PRV in this instance highlights that, in an era of unprecedented virus discovery, detection of viral infection does not necessarily imply bodily harm and that viral load is not always a suitable predictor of disease within a host organism.
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Affiliation(s)
- Yangfan Zhang
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
| | - Mark P Polinski
- Aquatic Diagnostics and Genomics Division, Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Phillip R Morrison
- Department of Zoology, The University of British Columbia, Vancouver, BC, Canada
| | - Colin J Brauner
- Department of Zoology, The University of British Columbia, Vancouver, BC, Canada
| | - Anthony P Farrell
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada.,Department of Zoology, The University of British Columbia, Vancouver, BC, Canada
| | - Kyle A Garver
- Aquatic Diagnostics and Genomics Division, Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
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22
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Nekouei O, Vanderstichel R, Ming T, Kaukinen KH, Thakur K, Tabata A, Laurin E, Tucker S, Beacham TD, Miller KM. Detection and Assessment of the Distribution of Infectious Agents in Juvenile Fraser River Sockeye Salmon, Canada, in 2012 and 2013. Front Microbiol 2018; 9:3221. [PMID: 30627126 PMCID: PMC6309813 DOI: 10.3389/fmicb.2018.03221] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 12/11/2018] [Indexed: 01/27/2023] Open
Abstract
Infectious diseases may contribute to declines in Fraser River Sockeye salmon (Oncorhynchus nerka) stocks, but a clear knowledge gap exists around which infectious agents and diseases are important. This study was conducted to: (1) determine the presence and prevalence of 46 infectious agents in juvenile Fraser River Sockeye salmon, and (2) evaluate spatial patterns in prevalence and burden over initial seaward migration, contrasting patterns between 2 years of average and poor productivity. In total, 2,006 out-migrating Sockeye salmon were collected from four regions along their migration trajectory in British Columbia, in 2012 and 2013. High-throughput microfluidics quantitative PCR was employed for simultaneous quantitation of 46 different infectious agents. Twenty-six agents were detected at least once, including nine with prevalence >5%. Candidatus Brachiomonas cysticola, Myxobolus arcticus, and Pacific salmon parvovirus were the most prevalent agents. Infectious agent diversity and burden increased consistently upon smolts entry into the ocean, but they did not substantially change afterwards. Notably, both freshwater- and saltwater-transmitted agents were more prevalent in 2013 than in 2012, leading to an overall higher infection burden in the first two sampling regions. A reduction in the prevalence of two agents, erythrocytic necrosis virus and Paraneuclospora theridion, was observed between regions 2 and 3, which was speculated to be associated with mortality during the 1st month at sea. The most prevalent infectious agents were all naturally occurring. In a small number of samples (0.9%), seven agents were only detected around and after salmon farming regions, including four important pathogens: piscine orthoreovirus, Piscirickettsia salmonis, Tenacibaculum maritimum, and Moritella viscosa. As the first synoptic survey of infectious agents in juvenile Sockeye salmon in British Columbia, this study provides the necessary baseline for further research on the most prevalent infectious agents and their potential pathogenicity, which may adversely affect the productivity of valuable Sockeye salmon stocks. In addition, our findings are informative to the decision makers involved in conservation programs.
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Affiliation(s)
- Omid Nekouei
- Department of Health Management, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Raphael Vanderstichel
- Department of Health Management, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Tobi Ming
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Karia H Kaukinen
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Krishna Thakur
- Department of Health Management, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Amy Tabata
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Emilie Laurin
- Department of Health Management, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Strahan Tucker
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Terry D Beacham
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - Kristina M Miller
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada.,Department of Forest & Conservation Sciences, The University of British Columbia, Vancouver, BC, Canada
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23
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Adamek M, Hellmann J, Flamm A, Teitge F, Vendramin N, Fey D, Riße K, Blakey F, Rimstad E, Steinhagen D. Detection of piscine orthoreoviruses (PRV-1 and PRV-3) in Atlantic salmon and rainbow trout farmed in Germany. Transbound Emerg Dis 2018; 66:14-21. [PMID: 30230250 DOI: 10.1111/tbed.13018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 08/06/2018] [Accepted: 09/06/2018] [Indexed: 01/10/2023]
Abstract
Piscine orthoreoviruses (PRVs) are emerging pathogens causing circulatory disorders in salmonids. PRV-1 is the etiological cause of heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar), characterized by epicarditis, inflammation and necrosis of the myocardium, myositis and necrosis of red skeletal muscle. In 2017, two German breeding farms for Atlantic salmon and rainbow trout (Oncorhynchus mykiss) experienced disease outbreaks with mortalities of 10% and 20% respectively. The main clinical signs were exhaustion and lethargic behaviour. During examinations, PRV-1 in salmon and PRV-3 in trout were detected for the first time in Germany. Further analyses also indicated the presence of Aeromonas salmonicida in internal tissues of both species. While PRV-1 could be putatively linked with the disease in Atlantic salmon, most of the rainbow trout suffered from an infection with A. salmonicida and not with PRV-3. Interestingly, the sequence analysis suggests that the German PRV-3 isolate is more similar to a Chilean PRV-3 isolate from Coho salmon (Oncorhynchus kisutch) than to PRV-3 from rainbow trout from Norway. This indicates a wide geographic distribution of this virus or dispersal by global trade. These findings indicate that infections with PRVs should be considered when investigating disease outbreaks in salmonids.
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Affiliation(s)
- Mikolaj Adamek
- Fish Disease Research Unit, Institute for Parasitology, University of Veterinary Medicine, Hannover, Germany
| | - John Hellmann
- Department Fisheries Ecology, North Rhine Westphalian State Agency for Nature, Environment and Consumer Protection, Albaum, Germany
| | - Agnes Flamm
- Hesse State Laboratory, Control of Fish Diseases, Giessen, Germany
| | - Felix Teitge
- Fish Disease Research Unit, Institute for Parasitology, University of Veterinary Medicine, Hannover, Germany
| | - Niccolò Vendramin
- Fish Diseases, Division for Diagnostics & Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - Daniel Fey
- Department Fisheries Ecology, North Rhine Westphalian State Agency for Nature, Environment and Consumer Protection, Albaum, Germany
| | - Karin Riße
- Hesse State Laboratory, Control of Fish Diseases, Giessen, Germany
| | - Franziska Blakey
- Hesse State Laboratory, Control of Fish Diseases, Giessen, Germany
| | - Espen Rimstad
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Dieter Steinhagen
- Fish Disease Research Unit, Institute for Parasitology, University of Veterinary Medicine, Hannover, Germany
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Kuehn R, Stoeckle BC, Young M, Popp L, Taeubert JE, Pfaffl MW, Geist J. Identification of a piscine reovirus-related pathogen in proliferative darkening syndrome (PDS) infected brown trout (Salmo trutta fario) using a next-generation technology detection pipeline. PLoS One 2018; 13:e0206164. [PMID: 30346982 PMCID: PMC6197672 DOI: 10.1371/journal.pone.0206164] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 10/08/2018] [Indexed: 01/02/2023] Open
Abstract
The proliferative darkening syndrome (PDS) is an annually recurring disease that causes species-specific die-off of brown trout (Salmo trutta fario) with a mortality rate of near 100% in pre-alpine rivers of central Europe. So far the etiology and causation of this disease is still unclear. The objective of this study was to identify the cause of PDS using a next-generation technology detection pipeline. Following the hypothesis that PDS is caused by an infectious agent, brown trout specimens were exposed to water from a heavily affected pre-alpine river with annual occurrence of the disease. Specimens were sampled over the entire time period from potential infection through death. Transcriptomic analysis (microarray) and RT-qPCR of brown trout liver tissue evidenced strong gene expression response of immune-associated genes. Messenger RNA of specimens with synchronous immune expression profiles were ultra-deep sequenced using next-generation sequencing technology (NGS). Bioinformatic processing of generated reads and gap-filling Sanger re-sequencing of the identified pathogen genome revealed strong evidence that a piscine-related reovirus is the causative organism of PDS. The identified pathogen is phylogenetically closely related to the family of piscine reoviruses (PRV) which are considered as the causation of different fish diseases in Atlantic and Pacific salmonid species such as Salmo salar and Onchorhynchus kisutch. This study also highlights that the approach of first screening immune responses along a timeline in order to identify synchronously affected stages in different specimens which subsequently were ultra-deep sequenced is an effective approach in pathogen detection. In particular, the identification of specimens with synchronous molecular immune response patterns combined with NGS sequencing and gap-filling re-sequencing resulted in the successful pathogen detection of PDS.
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Affiliation(s)
- Ralph Kuehn
- Unit of Molecular Zoology, Department of Zoology, Technical University of Munich, Freising, Germany.,Department of Fish, Wildlife and Conservation Ecology, New Mexico State University, Las Cruces, NM, United States of America
| | - Bernhard C Stoeckle
- Unit of Molecular Zoology, Department of Zoology, Technical University of Munich, Freising, Germany.,Aquatic Systems Biology Unit, Department of Ecology and Ecosystem Management, Technical University of Munich, Freising, Germany
| | - Marc Young
- Unit of Molecular Zoology, Department of Zoology, Technical University of Munich, Freising, Germany
| | - Lisa Popp
- Unit of Molecular Zoology, Department of Zoology, Technical University of Munich, Freising, Germany
| | - Jens-Eike Taeubert
- Fachberatung für Fischerei Niederbayern, Bezirk Niederbayern, Landshut, Germany
| | - Michael W Pfaffl
- Department of Animal Physiology and Immunology, Technical University of Munich, Freising, Germany
| | - Juergen Geist
- Aquatic Systems Biology Unit, Department of Ecology and Ecosystem Management, Technical University of Munich, Freising, Germany
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25
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Madhun AS, Isachsen CH, Omdal LM, Einen ACB, Maehle S, Wennevik V, Niemelä E, Svåsand T, Karlsbakk E. Prevalence of piscine orthoreovirus and salmonid alphavirus in sea-caught returning adult Atlantic salmon (Salmo salar L.) in northern Norway. JOURNAL OF FISH DISEASES 2018; 41:797-803. [PMID: 29388217 DOI: 10.1111/jfd.12785] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/29/2017] [Accepted: 12/29/2017] [Indexed: 06/07/2023]
Abstract
Heart and skeletal muscle inflammation (HSMI) caused by piscine orthoreovirus (PRV) and pancreas disease (PD) caused by salmonid alphavirus (SAV) are among the most prevalent viral diseases of Atlantic salmon farmed in Norway. There are limited data about the impact of disease in farmed salmon on wild salmon populations. Therefore, the prevalence of PRV and SAV in returning salmon caught in six sea sites was determined using real-time RT-PCR analyses. Of 419 salmon tested, 15.8% tested positive for PRV, while none were positive for SAV. However, scale reading revealed that 10% of the salmon had escaped from farms. The prevalence of PRV in wild salmon (8%) was significantly lower than in farm escapees (86%), and increased with fish length (proxy for age). Sequencing of the S1 gene of PRV from 39 infected fish revealed a mix of genotypes. The observed increase in PRV prevalence with fish age and the lack of phylogeographic structure of the virus could be explained by virus transmission in the feeding areas. Our results highlight the need for studies about the prevalence of PRV and other pathogens in Atlantic salmon in its oceanic phase.
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Affiliation(s)
- A S Madhun
- Institute of Marine Research, Bergen, Norway
| | | | - L M Omdal
- Institute of Marine Research, Bergen, Norway
| | - A C B Einen
- Institute of Marine Research, Bergen, Norway
| | - S Maehle
- Institute of Marine Research, Bergen, Norway
| | - V Wennevik
- Institute of Marine Research, Bergen, Norway
| | - E Niemelä
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - T Svåsand
- Institute of Marine Research, Bergen, Norway
| | - E Karlsbakk
- Institute of Marine Research, Bergen, Norway
- Department of Biology, University of Bergen, Bergen, Norway
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26
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Molecular and Antigenic Characterization of Piscine orthoreovirus (PRV) from Rainbow Trout (Oncorhynchus mykiss). Viruses 2018; 10:v10040170. [PMID: 29614838 PMCID: PMC5923464 DOI: 10.3390/v10040170] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 03/23/2018] [Accepted: 03/28/2018] [Indexed: 01/01/2023] Open
Abstract
Piscine orthoreovirus (PRV-1) causes heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). Recently, a novel PRV (formerly PRV-Om, here called PRV-3), was found in rainbow trout (Oncorhynchus mykiss) with HSMI-like disease. PRV is considered to be an emerging pathogen in farmed salmonids. In this study, molecular and antigenic characterization of PRV-3 was performed. Erythrocytes are the main target cells for PRV, and blood samples that were collected from experimentally challenged fish were used as source of virus. Virus particles were purified by gradient ultracentrifugation and the complete coding sequences of PRV-3 were obtained by Illumina sequencing. When compared to PRV-1, the nucleotide identity of the coding regions was 80.1%, and the amino acid identities of the predicted PRV-3 proteins varied from 96.7% (λ1) to 79.1% (σ3). Phylogenetic analysis showed that PRV-3 belongs to a separate cluster. The region encoding σ3 were sequenced from PRV-3 isolates collected from rainbow trout in Europe. These sequences clustered together, but were distant from PRV-3 that was isolated from rainbow trout in Norway. Bioinformatic analyses of PRV-3 proteins revealed that predicted secondary structures and functional domains were conserved between PRV-3 and PRV-1. Rabbit antisera raised against purified virus or various recombinant virus proteins from PRV-1 all cross-reacted with PRV-3. Our findings indicate that despite different species preferences of the PRV subtypes, several genetic, antigenic, and structural properties are conserved between PRV-1 and-3.
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27
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Purcell MK, Powers RL, Evered J, Kerwin J, Meyers TR, Stewart B, Winton JR. Molecular testing of adult Pacific salmon and trout (Oncorhynchus spp.) for several RNA viruses demonstrates widespread distribution of piscine orthoreovirus in Alaska and Washington. JOURNAL OF FISH DISEASES 2018; 41:347-355. [PMID: 29159930 DOI: 10.1111/jfd.12740] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 06/07/2023]
Abstract
This research was initiated in conjunction with a systematic, multiagency surveillance effort in the United States (U.S.) in response to reported findings of infectious salmon anaemia virus (ISAV) RNA in British Columbia, Canada. In the systematic surveillance study reported in a companion paper, tissues from various salmonids taken from Washington and Alaska were surveyed for ISAV RNA using the U.S.-approved diagnostic method, and samples were released for use in this present study only after testing negative. Here, we tested a subset of these samples for ISAV RNA with three additional published molecular assays, as well as for RNA from salmonid alphavirus (SAV), piscine myocarditis virus (PMCV) and piscine orthoreovirus (PRV). All samples (n = 2,252; 121 stock cohorts) tested negative for RNA from ISAV, PMCV, and SAV. In contrast, there were 25 stock cohorts from Washington and Alaska that had one or more individuals test positive for PRV RNA; prevalence within stocks varied and ranged from 2% to 73%. The overall prevalence of PRV RNA-positive individuals across the study was 3.4% (77 of 2,252 fish tested). Findings of PRV RNA were most common in coho (Oncorhynchus kisutch Walbaum) and Chinook (O. tshawytscha Walbaum) salmon.
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Affiliation(s)
- M K Purcell
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA, USA
| | - R L Powers
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA, USA
| | - J Evered
- U.S. Fish and Wildlife Service, Olympia Fish Health Center, Lacey, WA, USA
| | - J Kerwin
- Washington Department of Fish and Wildlife, Olympia, WA, USA
| | - T R Meyers
- Division of Commercial Fisheries, Alaska Department of Fish and Game, Juneau, AK, USA
| | - B Stewart
- Northwest Indian Fisheries Commission, Olympia, WA, USA
| | - J R Winton
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA, USA
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28
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Morton A, Routledge R, Hrushowy S, Kibenge M, Kibenge F. The effect of exposure to farmed salmon on piscine orthoreovirus infection and fitness in wild Pacific salmon in British Columbia, Canada. PLoS One 2017; 12:e0188793. [PMID: 29236731 PMCID: PMC5728458 DOI: 10.1371/journal.pone.0188793] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 11/13/2017] [Indexed: 12/29/2022] Open
Abstract
The disease Heart and Skeletal Muscle Inflammation (HSMI) is causing substantial economic losses to the Norwegian salmon farming industry where the causative agent, piscine orthoreovirus (PRV), is reportedly spreading from farmed to wild Atlantic salmon (Salmo salar) with as yet undetermined impacts. To assess if PRV infection is epidemiologically linked between wild and farmed salmon in the eastern Pacific, wild Pacific salmon (Oncorhynchus sp.) from regions designated as high or low exposure to salmon farms and farmed Atlantic salmon reared in British Columbia (BC) were tested for PRV. The proportion of PRV infection in wild fish was related to exposure to salmon farms (p = 0.0097). PRV was detected in: 95% of farmed Atlantic salmon, 37-45% of wild salmon from regions highly exposed to salmon farms and 5% of wild salmon from the regions furthest from salmon farms. The proportion of PRV infection was also significantly lower (p = 0.0008) where wild salmon had been challenged by an arduous return migration into high-elevation spawning habitat. Inter-annual PRV infection declined in both wild and farmed salmon from 2012-2013 (p ≤ 0.002). These results suggest that PRV transfer is occurring from farmed Atlantic salmon to wild Pacific salmon, that infection in farmed salmon may be influencing infection rates in wild salmon, and that this may pose a risk of reduced fitness in wild salmon impacting their survival and reproduction.
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Affiliation(s)
- Alexandra Morton
- Raincoast Research Society, Sointula, British Columbia, Canada
- * E-mail:
| | - Richard Routledge
- Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Stacey Hrushowy
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Molly Kibenge
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Frederick Kibenge
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
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29
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Kibenge MJT, Wang Y, Morton A, Routledge R, Kibenge FSB. Formal comment on: Piscine reovirus: Genomic and molecular phylogenetic analysis from farmed and wild salmonids collected on the Canada/US Pacific Coast. PLoS One 2017; 12:e0188690. [PMID: 29190697 PMCID: PMC5708765 DOI: 10.1371/journal.pone.0188690] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 10/31/2017] [Indexed: 11/18/2022] Open
Affiliation(s)
- Molly J. T. Kibenge
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Yingwei Wang
- School of Mathematical and Computational Sciences, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | | | - Richard Routledge
- Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Frederick S. B. Kibenge
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
- * E-mail:
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30
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Wessel Ø, Braaen S, Alarcon M, Haatveit H, Roos N, Markussen T, Tengs T, Dahle MK, Rimstad E. Infection with purified Piscine orthoreovirus demonstrates a causal relationship with heart and skeletal muscle inflammation in Atlantic salmon. PLoS One 2017; 12:e0183781. [PMID: 28841684 PMCID: PMC5571969 DOI: 10.1371/journal.pone.0183781] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 08/10/2017] [Indexed: 01/07/2023] Open
Abstract
Viral diseases pose a significant threat to the productivity in aquaculture. Heart- and skeletal muscle inflammation (HSMI) is an emerging disease in Atlantic salmon (Salmo salar) farming. HSMI is associated with Piscine orthoreovirus (PRV) infection, but PRV is ubiquitous in farmed Atlantic salmon and thus present also in apparently healthy individuals. This has brought speculations if additional etiological factors are required, and experiments focusing on the causal relationship between PRV and HSMI are highly warranted. A major bottleneck in PRV research has been the lack of cell lines that allow propagation of the virus. To bypass this, we propagated PRV in salmon, bled the fish at the peak of the infection, and purified virus particles from blood cells. Electron microscopy, western blot and high-throughput sequencing all verified the purity of the viral particles. Purified PRV particles were inoculated into naïve Atlantic salmon. The purified virus replicated in inoculated fish, spread to naïve cohabitants, and induced histopathological changes consistent with HSMI. PRV specific staining was demonstrated in the pathological lesions. A dose-dependent response was observed; a high dose of virus gave earlier peak of the viral load and development of histopathological changes compared to a lower dose, but no difference in the severity of the disease. The experiment demonstrated that PRV can be purified from blood cells, and that PRV is the etiological agent of HSMI in Atlantic salmon.
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Affiliation(s)
- Øystein Wessel
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
- * E-mail:
| | - Stine Braaen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | | | - Hanne Haatveit
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Norbert Roos
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Turhan Markussen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Torstein Tengs
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | | | - Espen Rimstad
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
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Bernatchez L, Wellenreuther M, Araneda C, Ashton DT, Barth JMI, Beacham TD, Maes GE, Martinsohn JT, Miller KM, Naish KA, Ovenden JR, Primmer CR, Young Suk H, Therkildsen NO, Withler RE. Harnessing the Power of Genomics to Secure the Future of Seafood. Trends Ecol Evol 2017; 32:665-680. [PMID: 28818341 DOI: 10.1016/j.tree.2017.06.010] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 06/16/2017] [Accepted: 06/20/2017] [Indexed: 11/15/2022]
Abstract
Best use of scientific knowledge is required to maintain the fundamental role of seafood in human nutrition. While it is acknowledged that genomic-based methods allow the collection of powerful data, their value to inform fisheries management, aquaculture, and biosecurity applications remains underestimated. We review genomic applications of relevance to the sustainable management of seafood resources, illustrate the benefits of, and identify barriers to their integration. We conclude that the value of genomic information towards securing the future of seafood does not need to be further demonstrated. Instead, we need immediate efforts to remove structural roadblocks and focus on ways that support integration of genomic-informed methods into management and production practices. We propose solutions to pave the way forward.
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Affiliation(s)
- Louis Bernatchez
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada.
| | - Maren Wellenreuther
- The New Zealand Institute for Plant & Food Research Limited, Port Nelson, Nelson 7043, New Zealand; Department of Biology, Lund University, Lund, Sweden
| | - Cristián Araneda
- Universidad de Chile, Facultad de Ciencias Agronómicas Departamento de Producción Animal, Avda. Santa Rosa 11315, La Pintana 8820808, Santiago, Chile
| | - David T Ashton
- The New Zealand Institute for Plant & Food Research Limited, Port Nelson, Nelson 7043, New Zealand
| | - Julia M I Barth
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Terry D Beacham
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, BC V9T 6N7, Canada
| | - Gregory E Maes
- Centre for Sustainable Tropical Fisheries and Aquaculture, Comparative Genomics Centre, College of Science and Engineering, James Cook University, Townsville, 4811 QLD, Australia; Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven (KU Leuven), B-3000 Leuven, Belgium; Genomics Core, UZ Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Jann T Martinsohn
- European Commission, Joint Research Centre (JRC), Directorate D - Sustainable Resources, Unit D2 - Water and Marine Resources, Via Enrico Fermi 2749, 21027 Ispra, Italy
| | - Kristina M Miller
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, BC V9T 6N7, Canada
| | - Kerry A Naish
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98105, USA
| | - Jennifer R Ovenden
- Molecular Fisheries Laboratory, School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Craig R Primmer
- Department of Biosciences, Institute of Biotechnology, 00014, University of Helsinki, Finland
| | - Ho Young Suk
- Department of Life Sciences, Yeungnam University, 280 Daehak-ro, Gyeongsan, Gyeongsangbuk-do 38541, South Korea
| | | | - Ruth E Withler
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, BC V9T 6N7, Canada
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32
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Lund M, Krudtaa Dahle M, Timmerhaus G, Alarcon M, Powell M, Aspehaug V, Rimstad E, Jørgensen SM. Hypoxia tolerance and responses to hypoxic stress during heart and skeletal muscle inflammation in Atlantic salmon (Salmo salar). PLoS One 2017; 12:e0181109. [PMID: 28700748 PMCID: PMC5507449 DOI: 10.1371/journal.pone.0181109] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 06/25/2017] [Indexed: 12/17/2022] Open
Abstract
Heart and skeletal muscle inflammation (HSMI) is associated with Piscine orthoreovirus (PRV) infection and is an important disease in Atlantic salmon (Salmo salar) aquaculture. Since PRV infects erythrocytes and farmed salmon frequently experience environmental hypoxia, the current study examined mutual effects of PRV infection and hypoxia on pathogenesis and fish performance. Furthermore, effects of HSMI on hypoxia tolerance, cardiorespiratory performance and blood oxygen transport were studied. A cohabitation trial including PRV-infected post-smolts exposed to periodic hypoxic stress (4 h of 40% O2; PRV-H) at 4, 7 and 10 weeks post-infection (WPI) and infected fish reared under normoxic conditions (PRV) was conducted. Periodic hypoxic stress did not influence infection levels or histopathological changes in the heart. Individual incipient lethal oxygen saturation (ILOS) was examined using a standardized hypoxia challenge test (HCT). At 7 WPI, i.e. peak level of infection, both PRV and PRV-H groups exhibited reduced hypoxia tolerance compared to non-infected fish. Three weeks later (10 WPI), during peak levels of pathological changes, reduced hypoxia tolerance was still observed for the PRV group while PRV-H performed equal to non-infected fish, implying a positive effect of the repeated exposure to hypoxic stress. This was in line with maximum heart rate (fHmax) measurements, showing equal performance of PRV-H and non-infected groups, but lower fHmax above 19°C as well as lower temperature optimum (Topt) for aerobic scope for PRV, suggesting reduced cardiac performance and thermal tolerance. In contrast, the PRV-H group had reduced hemoglobin-oxygen affinity compared to non-infected fish. In conclusion, Atlantic salmon suffering from HSMI have reduced hypoxia tolerance and cardiac performance, which can be improved by preconditioning fish to transient hypoxic stress episodes.
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Affiliation(s)
- Morten Lund
- Section of Immunology, Norwegian Veterinary Institute, Oslo and Harstad, Norway
- * E-mail:
| | - Maria Krudtaa Dahle
- Section of Immunology, Norwegian Veterinary Institute, Oslo and Harstad, Norway
| | - Gerrit Timmerhaus
- Nofima AS, Norwegian Institute of Food, Fisheries & Aquaculture Research, Ås, Norway
| | - Marta Alarcon
- Section of Immunology, Norwegian Veterinary Institute, Oslo and Harstad, Norway
| | - Mark Powell
- University of Bergen, Bergen, Norway
- Norwegian Institute for Water Research, Bergen, Norway
| | | | - Espen Rimstad
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Sven Martin Jørgensen
- Nofima AS, Norwegian Institute of Food, Fisheries & Aquaculture Research, Ås, Norway
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33
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Hauge H, Vendramin N, Taksdal T, Olsen AB, Wessel Ø, Mikkelsen SS, Alencar ALF, Olesen NJ, Dahle MK. Infection experiments with novel Piscine orthoreovirus from rainbow trout (Oncorhynchus mykiss) in salmonids. PLoS One 2017; 12:e0180293. [PMID: 28678799 PMCID: PMC5497981 DOI: 10.1371/journal.pone.0180293] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 06/13/2017] [Indexed: 01/12/2023] Open
Abstract
A new disease in farmed rainbow trout (Onchorhyncus mykiss) was described in Norway in 2013. The disease mainly affected the heart and resembled heart and skeletal muscle inflammation (HSMI) in Atlantic salmon (Salmo salar L.). HSMI is associated with Piscine orthoreovirus (PRV), and a search for a similar virus in the diseased rainbow trout led to detection of a sequence with 85% similarity to PRV. This finding called for a targeted effort to assess the risk the new PRV-variant pose on farmed rainbow trout and Atlantic salmon by studying infection and disease pathogenesis, aiming to provide more diagnostic knowledge. Based on the genetic relationship to PRV, the novel virus is referred to as PRV-Oncorhynchus mykiss (PRV-Om) in contrast to PRV-Salmo salar (PRV-Ss). In experimental trials, intraperitoneally injected PRV-Om was shown to replicate in blood in both salmonid species, but more effectively in rainbow trout. In rainbow trout, the virus levels peaked in blood and heart of cohabitants 6 weeks post challenge, along with increased expression of antiviral genes (Mx and viperin) in the spleen, with 80-100% of the cohabitants infected. Heart inflammation was diagnosed in all cohabitants examined 8 weeks post challenge. In contrast, less than 50% of the Atlantic salmon cohabitants were infected between 8 and 16 weeks post challenge and the antiviral response in these fish was very low. From 12 weeks post challenge and onwards, mild focal myocarditis was demonstrated in a few virus-positive salmon. In conclusion, PRV-Om infects both salmonid species, but faster transmission, more notable antiviral response and more prominent heart pathology were observed in rainbow trout.
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Affiliation(s)
- Helena Hauge
- Norwegian Veterinary Institute, Oslo & Bergen, Norway
| | - Niccolo Vendramin
- National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
| | | | | | - Øystein Wessel
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | | | | | - Niels Jørgen Olesen
- National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
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Bass AL, Hinch SG, Teffer AK, Patterson DA, Miller KM. A survey of microparasites present in adult migrating Chinook salmon (Oncorhynchus tshawytscha) in south-western British Columbia determined by high-throughput quantitative polymerase chain reaction. JOURNAL OF FISH DISEASES 2017; 40:453-477. [PMID: 28188649 DOI: 10.1111/jfd.12607] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/07/2016] [Accepted: 12/10/2016] [Indexed: 05/06/2023]
Abstract
Microparasites play an important role in the demography, ecology and evolution of Pacific salmonids. As salmon stocks continue to decline and the impacts of global climate change on fish populations become apparent, a greater understanding of microparasites in wild salmon populations is warranted. We used high-throughput, quantitative PCR (HT-qRT-PCR) to rapidly screen 82 adult Chinook salmon from five geographically or genetically distinct groups (mostly returning to tributaries of the Fraser River) for 45 microparasite taxa. We detected 20 microparasite species, four of which have not previously been documented in Chinook salmon, and four of which have not been previously detected in any salmonids in the Fraser River. Comparisons of microparasite load to blood plasma variables revealed some positive associations between Flavobacterium psychrophilum, Cryptobia salmositica and Ceratonova shasta and physiological indices suggestive of morbidity. We include a comparison of our findings for each microparasite taxa with previous knowledge of its distribution in British Columbia.
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Affiliation(s)
- A L Bass
- Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada
| | - S G Hinch
- Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada
| | - A K Teffer
- Biology Department, University of Victoria, Victoria, BC, Canada
| | - D A Patterson
- Fisheries and Oceans Canada, Science Branch, Cooperative Resource Management Institute, School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC, Canada
| | - K M Miller
- Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
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Teige LH, Lund M, Haatveit HM, Røsæg MV, Wessel Ø, Dahle MK, Storset AK. A bead based multiplex immunoassay detects Piscine orthoreovirus specific antibodies in Atlantic salmon (Salmo salar). FISH & SHELLFISH IMMUNOLOGY 2017; 63:491-499. [PMID: 28254501 DOI: 10.1016/j.fsi.2017.02.043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 02/16/2017] [Accepted: 02/24/2017] [Indexed: 06/06/2023]
Abstract
Future growth in aquaculture relies strongly on the control of diseases and pathogens. Vaccination has been a successful strategy for obtaining control of bacterial diseases in fish, but for viral diseases, vaccine development has been more challenging. Effective long-term protection against viral infections is not yet fully understood for fish, and in addition, optimal tools to monitor adaptive immunity are limited. Assays that can detect specific antibodies produced in response to viral infection in fish are still in their early development. Multiplex bead based assays have many advantages over traditional assays, since they are more sensitive and allow detection of multiple antigen-specific antibodies simultaneously in very small amounts of plasma or serum. In the present study, a bead based assay have been developed for detection of plasma IgM directed against Piscine orthoreovirus (PRV), the virus associated with the disease Heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon. Using recombinant PRV proteins coated on beads, antibodies targeting the structural outer capsid protein μ1 and the non-structural protein μNS were detected. Results from a PRV cohabitation challenge trial indicated that the antibody production was initiated approximately two weeks after the peak phase of PRV infection, coinciding with typical HSMI pathology. Thereafter, the antibody production increased while the epicardial inflammation became less prominent. In conclusion, the novel assay can detect PRV-specific antibodies that may play a role in viral defence. The bead-based immunoassay represents a valuable tool for studies on HSMI and possibly other diseases in aquaculture.
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Affiliation(s)
- Lena Hammerlund Teige
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, N-0454 Oslo, Norway
| | - Morten Lund
- Norwegian Veterinary Institute, N-0454 Oslo, Norway
| | - Hanne M Haatveit
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, N-0454 Oslo, Norway
| | - Magnus Vikan Røsæg
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, N-0454 Oslo, Norway; SalMar ASA, N-7266 Kverva, Norway
| | - Øystein Wessel
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, N-0454 Oslo, Norway
| | - Maria K Dahle
- Norwegian Veterinary Institute, N-0454 Oslo, Norway.
| | - Anne K Storset
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, N-0454 Oslo, Norway
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Haatveit HM, Wessel Ø, Markussen T, Lund M, Thiede B, Nyman IB, Braaen S, Dahle MK, Rimstad E. Viral Protein Kinetics of Piscine Orthoreovirus Infection in Atlantic Salmon Blood Cells. Viruses 2017; 9:E49. [PMID: 28335455 PMCID: PMC5371804 DOI: 10.3390/v9030049] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/07/2017] [Accepted: 03/10/2017] [Indexed: 01/12/2023] Open
Abstract
Piscine orthoreovirus (PRV) is ubiquitous in farmed Atlantic salmon (Salmo salar) and the cause of heart and skeletal muscle inflammation. Erythrocytes are important target cells for PRV. We have investigated the kinetics of PRV infection in salmon blood cells. The findings indicate that PRV causes an acute infection of blood cells lasting 1-2 weeks, before it subsides into persistence. A high production of viral proteins occurred initially in the acute phase which significantly correlated with antiviral gene transcription. Globular viral factories organized by the non-structural protein µNS were also observed initially, but were not evident at later stages. Interactions between µNS and the PRV structural proteins λ1, µ1, σ1 and σ3 were demonstrated. Different size variants of µNS and the outer capsid protein µ1 appeared at specific time points during infection. Maximal viral protein load was observed five weeks post cohabitant challenge and was undetectable from seven weeks post challenge. In contrast, viral RNA at a high level could be detected throughout the eight-week trial. A proteolytic cleavage fragment of the µ1 protein was the only viral protein detectable after seven weeks post challenge, indicating that this µ1 fragment may be involved in the mechanisms of persistent infection.
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Affiliation(s)
- Hanne Merethe Haatveit
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
| | - Øystein Wessel
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
| | - Turhan Markussen
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
| | - Morten Lund
- Department of Immunology, Norwegian Veterinary Institute, 0454 Oslo, Norway.
| | - Bernd Thiede
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
| | - Ingvild Berg Nyman
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
| | - Stine Braaen
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
| | - Maria Krudtaa Dahle
- Department of Immunology, Norwegian Veterinary Institute, 0454 Oslo, Norway.
| | - Espen Rimstad
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
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Di Cicco E, Ferguson HW, Schulze AD, Kaukinen KH, Li S, Vanderstichel R, Wessel Ø, Rimstad E, Gardner IA, Hammell KL, Miller KM. Heart and skeletal muscle inflammation (HSMI) disease diagnosed on a British Columbia salmon farm through a longitudinal farm study. PLoS One 2017; 12:e0171471. [PMID: 28225783 PMCID: PMC5321275 DOI: 10.1371/journal.pone.0171471] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 01/20/2017] [Indexed: 01/24/2023] Open
Abstract
Heart and skeletal muscle inflammation (HSMI) is an emerging disease of marine-farmed Atlantic Salmon (Salmo salar), first recognized in 1999 in Norway, and later also reported in Scotland and Chile. We undertook a longitudinal study involving health evaluation over an entire marine production cycle on one salmon farm in British Columbia (Canada). In previous production cycles at this farm site and others in the vicinity, cardiac lesions not linked to a specific infectious agent or disease were identified. Histologic assessments of both live and moribund fish samples collected at the farm during the longitudinal study documented at the population level the development, peak, and recovery phases of HSMI. The fish underwent histopathological evaluation of all tissues, Twort’s Gram staining, immunohistochemistry, and molecular quantification in heart tissue of 44 agents known or suspected to cause disease in salmon. Our analysis showed evidence of HSMI histopathological lesions over an 11-month timespan, with the prevalence of lesions peaking at 80–100% in sampled fish, despite mild clinical signs with no associated elevation in mortalities reported at the farm level. Diffuse mononuclear inflammation and myodegeneration, consistent with HSMI, was the predominant histologic observation in affected heart and skeletal muscle. Infective agent monitoring identified three agents at high prevalence in salmon heart tissue, including Piscine orthoreovirus (PRV), and parasites Paranucleospora theridion and Kudoa thyrsites. However, PRV alone was statistically correlated with the occurrence and severity of histopathological lesions in the heart. Immunohistochemical staining further localized PRV throughout HSMI development, with the virus found mainly within red blood cells in early cases, moving into the cardiomyocytes within or, more often, on the periphery of the inflammatory reaction during the peak disease, and reducing to low or undetectable levels later in the production cycle. This study represents the first longitudinal assessment of HSMI in a salmon farm in British Columbia, providing new insights on the pathogenesis of the disease.
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Affiliation(s)
- Emiliano Di Cicco
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
- Pacific Salmon Foundation, Vancouver, British Columbia, Canada
- * E-mail: (ED); (KMM)
| | - Hugh W. Ferguson
- School of Veterinary Medicine, St. George's University, Grenada, W. Indies
| | - Angela D. Schulze
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | - Karia H. Kaukinen
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | - Shaorong Li
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | - Raphaël Vanderstichel
- Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Øystein Wessel
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Espen Rimstad
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Ian A. Gardner
- Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - K. Larry Hammell
- Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Kristina M. Miller
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
- * E-mail: (ED); (KMM)
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Miller KM, Günther OP, Li S, Kaukinen KH, Ming TJ. Molecular indices of viral disease development in wild migrating salmon †. CONSERVATION PHYSIOLOGY 2017; 5:cox036. [PMID: 28702195 PMCID: PMC5499884 DOI: 10.1093/conphys/cox036] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/08/2017] [Accepted: 05/25/2017] [Indexed: 05/07/2023]
Abstract
Infectious diseases can impact the physiological performance of individuals, including their mobility, visual acuity, behavior and tolerance and ability to effectively respond to additional stressors. These physiological effects can influence competitiveness, social hierarchy, habitat usage, migratory behavior and risk to predation, and in some circumstances, viability of populations. While there are multiple means of detecting infectious agents (microscopy, culture, molecular assays), the detection of infectious diseases in wild populations in circumstances where mortality is not observable can be difficult. Moreover, if infection-related physiological compromise leaves individuals vulnerable to predation, it may be rare to observe wildlife in a late stage of disease. Diagnostic technologies designed to diagnose cause of death are not always sensitive enough to detect early stages of disease development in live-sampled organisms. Sensitive technologies that can differentiate agent carrier states from active disease states are required to demonstrate impacts of infectious diseases in wild populations. We present the discovery and validation of salmon host transcriptional biomarkers capable of distinguishing fish in an active viral disease state [viral disease development (VDD)] from those carrying a latent viral infection, and viral versus bacterial disease states. Biomarker discovery was conducted through meta-analysis of published and in-house microarray data, and validation performed on independent datasets including disease challenge studies and farmed salmon diagnosed with various viral, bacterial and parasitic diseases. We demonstrate that the VDD biomarker panel is predictive of disease development across RNA-viral species, salmon species and salmon tissues, and can recognize a viral disease state in wild-migrating salmon. Moreover, we show that there is considerable overlap in the biomarkers resolved in our study in salmon with those based on similar human viral influenza research, suggesting a highly conserved suite of host genes associated with viral disease that may be applicable across a broad range of vertebrate taxa.
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Affiliation(s)
- Kristina M. Miller
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, Canada V9T 6N7
- Corresponding author: Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, Canada V9T 6N7.
| | - Oliver P. Günther
- Günther Analytics, 402-5775 Hampton Place, Vancouver, British Columbia, Canada V6T 2G6
| | - Shaorong Li
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, Canada V9T 6N7
| | - Karia H. Kaukinen
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, Canada V9T 6N7
| | - Tobi J. Ming
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, Canada V9T 6N7
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Powell MD, Yousaf MN. Cardiovascular Effects of Disease: Parasites and Pathogens. FISH PHYSIOLOGY 2017. [DOI: 10.1016/bs.fp.2017.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Wiik-Nielsen J, Alarcón M, Jensen BB, Haugland Ø, Mikalsen AB. Viral co-infections in farmed Atlantic salmon, Salmo salar L., displaying myocarditis. JOURNAL OF FISH DISEASES 2016; 39:1495-1507. [PMID: 27146423 DOI: 10.1111/jfd.12487] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/11/2016] [Accepted: 03/14/2016] [Indexed: 06/05/2023]
Abstract
Several different viruses have been associated with myocarditis-related diseases in the Atlantic salmon aquaculture industry. In this study, we investigated the presence of PMCV, SAV, PRV and the recently identified Atlantic salmon calicivirus (ASCV), alone and as co-infections in farmed Atlantic salmon displaying myocarditis. The analyses were performed at the individual level and comprised qPCR and histopathological examination of 397 salmon from 25 farms along the Norwegian coast. The samples were collected in 2009 and 2010, 5-22 months post-sea transfer. The study documented multiple causes of myocarditis and revealed co-infections including individual fish infected with all four viruses. There was an overall correlation between lesions characteristic of CMS and PD and the presence of PMCV and SAV, respectively. Although PRV was ubiquitously present, high viral loads were with a few exceptions, correlated with lesions characteristic of HSMI. ASCV did not seem to have any impact on myocardial infection by PMCV, SAV or PRV. qPCR indicated a negative correlation between PMCV and SAV viral loads. Co-infections result in mixed and atypical pathological changes which pose a challenge for disease diagnostic work.
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Affiliation(s)
| | - M Alarcón
- Norwegian Veterinary Institute, Oslo, Norway
| | | | - Ø Haugland
- Norwegian University of Life Sciences, Department of Basic Science and Aquatic Medicine, Oslo, Norway
| | - A B Mikalsen
- Norwegian University of Life Sciences, Department of Basic Science and Aquatic Medicine, Oslo, Norway
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Polinski MP, Bradshaw JC, Inkpen SM, Richard J, Fritsvold C, Poppe TT, Rise ML, Garver KA, Johnson SC. De novo assembly of Sockeye salmon kidney transcriptomes reveal a limited early response to piscine reovirus with or without infectious hematopoietic necrosis virus superinfection. BMC Genomics 2016; 17:848. [PMID: 27806699 PMCID: PMC5094019 DOI: 10.1186/s12864-016-3196-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 10/22/2016] [Indexed: 12/19/2022] Open
Abstract
Background Piscine reovirus (PRV) has been associated with the serious disease known as Heart and Skeletal Muscle Inflammation (HSMI) in cultured Atlantic salmon Salmo salar in Norway. PRV is also prevalent in wild and farmed salmon without overt disease manifestations, suggesting multifactorial triggers or PRV variant-specific factors are required to initiate disease. In this study, we explore the head kidney transcriptome of Sockeye salmon Oncorhynchus nerka during early PRV infection to identify host responses in the absence of disease in hopes of elucidating mechanisms by which PRV may directly alter host functions and contribute to the development of a disease state. We further investigate the role of PRV as a coinfecting agent following superinfection with infectious hematopoietic necrosis virus (IHNV) – a highly pathogenic rhabdovirus endemic to the west coast of North America. Results Challenge of Sockeye salmon with PRV resulted in high quantities of viral transcripts to become present in the blood and kidney of infected fish without manifestations of disease. De novo transcriptome assembly of over 2.3 billion paired RNA-seq reads from the head kidneys of 36 fish identified more than 320,000 putative unigenes, of which less than 20 were suggested to be differentially expressed in response to PRV at either 2 or 3 weeks post challenge by DESeq2 and edgeR analysis. Of these, only one, Ependymin, was confirmed to be differentially expressed by qPCR in an expanded sample set. In contrast, IHNV induced substantial transcriptional changes (differential expression of > 20,000 unigenes) which included transcripts involved in antiviral and inflammatory response pathways. Prior infection with PRV had no significant effect on host responses to superinfecting IHNV, nor did host responses initiated by IHNV exposure influence increasing PRV loads. Conclusions PRV does not substantially alter the head kidney transcriptome of Sockeye salmon during early (2 to 3 week) infection and dissemination in a period of significant increasing viral load, nor does the presence of PRV change the host transcriptional response to an IHNV superinfection. Further, concurrent infections of PRV and IHNV do not appear to significantly influence the infectivity or severity of IHNV associated disease, or conversely, PRV load. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3196-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mark P Polinski
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Rd, Nanaimo, BC, V9T6N7, Canada.
| | - Julia C Bradshaw
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Rd, Nanaimo, BC, V9T6N7, Canada
| | - Sabrina M Inkpen
- Department of Ocean Sciences, Memorial University, St. John's, NF, A1C5S7, Canada
| | - Jon Richard
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Rd, Nanaimo, BC, V9T6N7, Canada
| | - Camilla Fritsvold
- Department of Pathology, Norwegian Veterinary Institute, Oslo, NO-0106, Norway
| | - Trygve T Poppe
- Department of Pathology, Norwegian Veterinary Institute, Oslo, NO-0106, Norway.,Department of Basic Sciences and Aquatic Medicine (Basam), Norwegian University of Life Sciences, P.O. Box 8146, Dep, N-0033, Oslo, Norway
| | - Matthew L Rise
- Department of Ocean Sciences, Memorial University, St. John's, NF, A1C5S7, Canada
| | - Kyle A Garver
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Rd, Nanaimo, BC, V9T6N7, Canada
| | - Stewart C Johnson
- Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Rd, Nanaimo, BC, V9T6N7, Canada
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Sibley SD, Finley MA, Baker BB, Puzach C, Armién AG, Giehtbrock D, Goldberg TL. Novel reovirus associated with epidemic mortality in wild largemouth bass (Micropterus salmoides). J Gen Virol 2016; 97:2482-2487. [DOI: 10.1099/jgv.0.000568] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Samuel D. Sibley
- Department of Pathobiological Sciences, University of Wisconsin–Madison, Madison, WI, USA
| | - Megan A. Finley
- Wisconsin Department of Natural Resources, Bureau of Fisheries Management, Madison, WI, USA
| | - Bridget B. Baker
- Wisconsin Department of Natural Resources, Bureau of Fisheries Management, Madison, WI, USA
| | - Corey Puzach
- United States Fish and Wildlife Service, La Crosse Fish Health Center, Onalaska, WI, USA
| | - Aníbal G. Armién
- Minnesota Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, USA
| | - David Giehtbrock
- Wisconsin Department of Natural Resources, Bureau of Fisheries Management, Madison, WI, USA
| | - Tony L. Goldberg
- Global Health Institute, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Department of Pathobiological Sciences, University of Wisconsin–Madison, Madison, WI, USA
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Siah A, Morrison DB, Fringuelli E, Savage P, Richmond Z, Johns R, Purcell MK, Johnson SC, Saksida SM. Correction: Piscine Reovirus: Genomic and Molecular Phylogenetic Analysis from Farmed and Wild Salmonids Collected on the Canada/US Pacific Coast. PLoS One 2016; 11:e0164926. [PMID: 27732682 PMCID: PMC5061418 DOI: 10.1371/journal.pone.0164926] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Madhun AS, Isachsen CH, Omdal LM, Bårdsgjære Einen AC, Bjørn PA, Nilsen R, Karlsbakk E. Occurrence of salmonid alphavirus (SAV) and piscine orthoreovirus (PRV) infections in wild sea trout Salmo trutta in Norway. DISEASES OF AQUATIC ORGANISMS 2016; 120:109-113. [PMID: 27409234 DOI: 10.3354/dao03009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Viral diseases represent a serious problem in Atlantic salmon (Salmo salar L.) farming in Norway. Pancreas disease (PD) caused by salmonid alphavirus (SAV) and heart and skeletal muscle inflammation (HSMI) caused by piscine orthoreovirus (PRV) are among the most frequently diagnosed viral diseases in recent years. The possible spread of viruses from salmon farms to wild fish is a major public concern. Sea trout S. trutta collected from the major farming areas along the Norwegian coast are likely to have been exposed to SAV and PRV from farms with disease outbreaks. We examined 843 sea trout from 4 counties in Norway for SAV and PRV infections. We did not detect SAV in any of the tested fish, although significant numbers of the trout were caught in areas with frequent PD outbreaks. Low levels of PRV were detected in 1.3% of the sea trout. PRV-infected sea trout were caught in both salmon farming and non-farming areas, so the occurrence of infections was not associated with farming intensity or HSMI cases. Our results suggest that SAV and PRV infections are uncommon in wild sea trout. Hence, we found no evidence that sea trout are at risk from SAV or PRV released from salmon farms.
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Godoy MG, Kibenge MJT, Wang Y, Suarez R, Leiva C, Vallejos F, Kibenge FSB. First description of clinical presentation of piscine orthoreovirus (PRV) infections in salmonid aquaculture in Chile and identification of a second genotype (Genotype II) of PRV. Virol J 2016; 13:98. [PMID: 27296722 PMCID: PMC4906990 DOI: 10.1186/s12985-016-0554-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 06/02/2016] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Heart and skeletal muscle inflammation (HSMI) is an emerging disease of marine-farmed Atlantic salmon Salmo salar, first recognized in 1999 in Norway, and recently associated with piscine orthoreovirus (PRV) infection. To date, HSMI lesions with presence of PRV have only been described in marine-farmed Atlantic salmon in Norway. A new HSMI-like disease in rainbow trout Oncorhynchus mykiss associated with a PRV-related virus has also been reported in Norway. METHODS Sampling of Atlantic salmon and coho salmon was done during potential disease outbreaks, targeting lethargic/moribund fish. Fish were necropsied and tissues were taken for histopathologic analysis and testing for PRV by RT-qPCR assay for segment L1 and conventional RT-PCR for PRV segment S1. The PCR products were sequenced and their relationship to PRV strains in GenBank was determined using phylogenetic analysis and nucleotide and amino acid homology comparisons. RESULTS The Atlantic salmon manifested the classical presentation of HSMI with high PRV virus loads (low Ct values) as described in Norway. The coho salmon with low Ct values had myocarditis but only in the spongy layer, the myositis of red muscle in general was mild, and the hepatic necrosis was severe. Upon phylogenetic analysis of PRV segment S1 sequences, all the Chilean PRV strains from Atlantic salmon grouped as sub-genotype Ib, whereas the Chilean PRV strains from coho salmon were more diversified, grouping in both sub-genotypes Ia and Ib and others forming a distinct new phylogenetic cluster, designated Genotype II that included the Norwegian PRV-related virus. CONCLUSIONS To our knowledge the present work constitutes the first published report of HSMI lesions with presence of PRV in farmed Atlantic salmon outside of Europe, and the first report of HSMI-like lesions with presence of PRV in coho salmon in Chile. The Chilean PRV strains from coho salmon are more genetically diversified than those from Atlantic salmon, and some form a distinct new phylogenetic cluster, designated Genotype II.
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Affiliation(s)
- Marcos G Godoy
- Centro de Investigaciones Biológicas Aplicadas (CIBA), Diego de Almagro Norte 1013, No. 8, Puerto Montt, Chile
- Facultad de Ciencias, Universidad San Sebastián, Lago Panguipulli 1390, Puerto Montt, Chile
- ETECMA, Diego de Almagro Norte 1013, No. 10, Puerto Montt, Chile
- Doctorado en Acuicultura, Programa Cooperativo Universidad de Chile, Universidad Católica del Norte, Antofagasta, Chile
- Doctorado en Acuicultura, Programa Cooperativo Universidad de Chile, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Molly J T Kibenge
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave, Charlottetown, PEI, C1A 4P3, Canada
| | - Yingwei Wang
- School of Mathematical and Computational Sciences, University of Prince Edward Island, 550 University Ave, Charlottetown, PEI, C1A 4P3, Canada
| | - Rudy Suarez
- Centro de Investigaciones Biológicas Aplicadas (CIBA), Diego de Almagro Norte 1013, No. 8, Puerto Montt, Chile
- ETECMA, Diego de Almagro Norte 1013, No. 10, Puerto Montt, Chile
| | - Camila Leiva
- Centro de Investigaciones Biológicas Aplicadas (CIBA), Diego de Almagro Norte 1013, No. 8, Puerto Montt, Chile
- , Present Address: Aquagestión S.A. Panamericana Sur 428, Puerto Montt, Chile
| | | | - Frederick S B Kibenge
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave, Charlottetown, PEI, C1A 4P3, Canada.
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Hauge H, Dahle M, Moldal T, Thoen E, Gjevre AG, Weli S, Alarcón M, Grove S. Piscine orthoreovirus can infect and shed through the intestine in experimentally challenged Atlantic salmon (Salmo salar L.). Vet Res 2016; 47:57. [PMID: 27216404 PMCID: PMC4877738 DOI: 10.1186/s13567-016-0343-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 05/09/2016] [Indexed: 12/17/2022] Open
Abstract
Piscine orthoreovirus (PRV) is a ubiquitous virus in Norwegian salmon farms associated with the disease heart and skeletal muscle inflammation (HSMI). Experimental challenge has shown that the virus replicates in circulating red blood cells of Atlantic salmon prior to infecting heart myocytes. The infection route from water to blood is however still unknown. The related mammalian orthoreovirus primarily infects the lungs and gastrointestinal (GI) tract and is proposed to spread mainly through the faecal–oral route. To investigate the role of the salmonid GI tract in PRV-infection, oral and anal administration of virus was compared to intraperitoneal (i.p.) injection. When administered anally, PRV was transferred to blood 4 days post challenge (dpc) and levels peaked at 42 dpc, similar to i.p. injected fish. PRV was detected in heart and faeces with corresponding kinetics, and inflammatory heart lesions consistent with HSMI were observed from 49 dpc. The orally intubated group showed slower virus kinetics in both blood and heart, and no signs of HSMI. Compared to the oral and i.p. administration routes, leakage of virus inoculate by anal intubation was minor and challenge was restricted to the mid- and distal intestine. These findings show that anal intubation is an efficacious method for PRV delivery to the GI tract and demonstrates that PRV can establish infection through the intestine with the potential for transmission via faeces.
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Affiliation(s)
- Helena Hauge
- Norwegian Veterinary Institute, Pb 750, Sentrum, 0106, Oslo, Norway.
| | - Maria Dahle
- Norwegian Veterinary Institute, Pb 750, Sentrum, 0106, Oslo, Norway
| | - Torfinn Moldal
- Norwegian Veterinary Institute, Pb 750, Sentrum, 0106, Oslo, Norway
| | - Even Thoen
- Norwegian Veterinary Institute, Pb 750, Sentrum, 0106, Oslo, Norway
| | - Anne-Gerd Gjevre
- Norwegian Veterinary Institute, Pb 750, Sentrum, 0106, Oslo, Norway
| | - Simon Weli
- Norwegian Veterinary Institute, Pb 750, Sentrum, 0106, Oslo, Norway
| | - Marta Alarcón
- Norwegian Veterinary Institute, Pb 750, Sentrum, 0106, Oslo, Norway
| | - Søren Grove
- Norwegian Veterinary Institute, Pb 750, Sentrum, 0106, Oslo, Norway
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Johansen LH, Dahle MK, Wessel Ø, Timmerhaus G, Løvoll M, Røsæg M, Jørgensen SM, Rimstad E, Krasnov A. Differences in gene expression in Atlantic salmon parr and smolt after challenge with Piscine orthoreovirus (PRV). Mol Immunol 2016; 73:138-50. [DOI: 10.1016/j.molimm.2016.04.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 12/25/2022]
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Garver KA, Marty GD, Cockburn SN, Richard J, Hawley LM, Müller A, Thompson RL, Purcell MK, Saksida S. Piscine reovirus, but not Jaundice Syndrome, was transmissible to Chinook Salmon, Oncorhynchus tshawytscha (Walbaum), Sockeye Salmon, Oncorhynchus nerka (Walbaum), and Atlantic Salmon, Salmo salar L. JOURNAL OF FISH DISEASES 2016; 39:117-28. [PMID: 25630226 DOI: 10.1111/jfd.12329] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 10/27/2014] [Accepted: 11/02/2014] [Indexed: 05/12/2023]
Abstract
A Jaundice Syndrome occurs sporadically among sea-pen-farmed Chinook Salmon in British Columbia, the westernmost province of Canada. Affected salmon are easily identified by a distinctive yellow discolouration of the abdominal and periorbital regions. Through traditional diagnostics, no bacterial or viral agents were cultured from tissues of jaundiced Chinook Salmon; however, piscine reovirus (PRV) was identified via RT-rPCR in all 10 affected fish sampled. By histopathology, Jaundice Syndrome is an acute to peracute systemic disease, and the time from first clinical signs to death is likely <48 h; renal tubular epithelial cell necrosis is the most consistent lesion. In an infectivity trial, Chinook Salmon, Sockeye Salmon and Atlantic Salmon, intraperitoneally inoculated with a PRV-positive organ homogenate from jaundiced Chinook Salmon, developed no gross or microscopic evidence of jaundice despite persistence of PRV for the 5-month holding period. The results from this study demonstrate that the Jaundice Syndrome was not transmissible by injection of material from infected fish and that PRV was not the sole aetiological factor for the condition. Additionally, these findings showed the Pacific coast strain of PRV, while transmissible, was of low pathogenicity for Atlantic Salmon, Chinook Salmon and Sockeye Salmon.
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Affiliation(s)
- K A Garver
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - G D Marty
- Animal Health Centre, Ministry of Agriculture, Abbotsford, BC, Canada
| | - S N Cockburn
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - J Richard
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - L M Hawley
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - A Müller
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada
| | - R L Thompson
- Western Fisheries Research Center, U.S. Geological Survey, Seattle, WA, USA
| | - M K Purcell
- Western Fisheries Research Center, U.S. Geological Survey, Seattle, WA, USA
| | - S Saksida
- British Columbia Centre for Aquatic Health Sciences, Campbell River, BC, Canada
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Garver KA, Johnson SC, Polinski MP, Bradshaw JC, Marty GD, Snyman HN, Morrison DB, Richard J. Piscine Orthoreovirus from Western North America Is Transmissible to Atlantic Salmon and Sockeye Salmon but Fails to Cause Heart and Skeletal Muscle Inflammation. PLoS One 2016; 11:e0146229. [PMID: 26730591 PMCID: PMC4701501 DOI: 10.1371/journal.pone.0146229] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 12/14/2015] [Indexed: 12/14/2022] Open
Abstract
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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Affiliation(s)
- Kyle A. Garver
- Pacific Biological Station, Department of Fisheries and Oceans, Nanaimo, British Columbia, Canada
- * E-mail:
| | - Stewart C. Johnson
- Pacific Biological Station, Department of Fisheries and Oceans, Nanaimo, British Columbia, Canada
| | - Mark P. Polinski
- Pacific Biological Station, Department of Fisheries and Oceans, Nanaimo, British Columbia, Canada
| | - Julia C. Bradshaw
- Pacific Biological Station, Department of Fisheries and Oceans, Nanaimo, British Columbia, Canada
| | - Gary D. Marty
- Animal Health Centre, Ministry of Agriculture, Abbotsford, British Columbia, Canada
| | - Heindrich N. Snyman
- Animal Health Centre, Ministry of Agriculture, Abbotsford, British Columbia, Canada
| | | | - Jon Richard
- Pacific Biological Station, Department of Fisheries and Oceans, Nanaimo, British Columbia, Canada
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Siah A, Morrison DB, Fringuelli E, Savage P, Richmond Z, Johns R, Purcell MK, Johnson SC, Saksida SM. Piscine Reovirus: Genomic and Molecular Phylogenetic Analysis from Farmed and Wild Salmonids Collected on the Canada/US Pacific Coast. PLoS One 2015; 10:e0141475. [PMID: 26536673 PMCID: PMC4633109 DOI: 10.1371/journal.pone.0141475] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 10/07/2015] [Indexed: 01/19/2023] Open
Abstract
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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Affiliation(s)
- Ahmed Siah
- British Columbia Centre for Aquatic Health Sciences, Campbell River, British Columbia, Canada
- * E-mail:
| | | | - Elena Fringuelli
- Veterinary Sciences Division, AFBI Stormont, Stoney Road, Belfast, United Kingdom
| | - Paul Savage
- Veterinary Sciences Division, AFBI Stormont, Stoney Road, Belfast, United Kingdom
| | - Zina Richmond
- British Columbia Centre for Aquatic Health Sciences, Campbell River, British Columbia, Canada
| | - Robert Johns
- British Columbia Centre for Aquatic Health Sciences, Campbell River, British Columbia, Canada
| | - Maureen K. Purcell
- US Geological Survey, Western Fisheries Research Center, Seattle, WA, United States of America
| | | | - Sonja M. Saksida
- British Columbia Centre for Aquatic Health Sciences, Campbell River, British Columbia, Canada
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