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Rounsville TF, Polinski MP, Marini AG, Turner SM, Vendramin N, Cuenca A, Pietrak MR, Peterson BC, Bouchard DA. Rapid differentiation of infectious salmon anemia virus avirulent (HPR0) from virulent (HPRΔ) variants using multiplex RT-qPCR. J Vet Diagn Invest 2024; 36:329-337. [PMID: 38212882 PMCID: PMC11110766 DOI: 10.1177/10406387231223290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024] Open
Abstract
Infectious salmon anemia virus (ISAV; Isavirus salaris) causes an economically important disease of Atlantic salmon (Salmo salar L.). ISA outbreaks have resulted in significant losses of farmed salmon globally, often with a sudden onset. However, 2 phenotypically distinct variants of ISAV exist, each with divergent disease outcomes, associated regulations, and control measures. ISAV-HPRΔ, also known as ISAV-HPR deleted, is responsible for ISA outbreaks; ISAV-HPR0, is avirulent and is not known to cause fish mortality. Current detection methodology requires genetic sequencing of ISAV-positive samples to differentiate phenotypes, which may slow responses to disease management. To increase the speed of phenotypic determinations of ISAV, we developed a new, rapid multiplex RT-qPCR method capable of 1) detecting if a sample contains any form of ISAV, 2) discriminating whether positive samples contain HPRΔ or HPR0, and 3) validating RNA extractions with an internal control, all in a single reaction. Following assay development and optimization, we validated this new multiplex on 31 ISAV strains collected from North America and Europe (28 ISAV-HPRΔ, 3 ISAV-HPR0). Finally, we completed an inter-laboratory comparison of this multiplex qPCR with commercial ISAV testing and found that both methods provided equivalent results for ISAV detection.
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Affiliation(s)
- Thomas F. Rounsville
- Pest Management Unit, University of Maine Cooperative Extension Diagnostic and Research Laboratory, Orono, ME, USA
| | - Mark P. Polinski
- National Cold Water Marine Aquaculture Center, U.S. Department of Agriculture–Agricultural Research Service, Franklin, ME, USA
| | - Alyssa G. Marini
- Pest Management Unit, University of Maine Cooperative Extension Diagnostic and Research Laboratory, Orono, ME, USA
- University of Maine School of Biology and Ecology, Orono, ME, USA
| | - Sarah M. Turner
- Aquatic Animal Health Laboratory, University of Maine Cooperative Extension Diagnostic and Research Laboratory, Orono, ME, USA
| | - Niccolò Vendramin
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Argelia Cuenca
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Michael R. Pietrak
- National Cold Water Marine Aquaculture Center, U.S. Department of Agriculture–Agricultural Research Service, Franklin, ME, USA
| | - Brian C. Peterson
- National Cold Water Marine Aquaculture Center, U.S. Department of Agriculture–Agricultural Research Service, Franklin, ME, USA
| | - Deborah A. Bouchard
- Aquatic Animal Health Laboratory, University of Maine Cooperative Extension Diagnostic and Research Laboratory, Orono, ME, USA
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Cárdenas M, Michelson S, Pérez DR, Montoya M, Toledo J, Vásquez-Martínez Y, Cortez-San Martin M. Infectious Salmon Anemia Virus Infectivity Is Determined by Multiple Segments with an Important Contribution from Segment 5. Viruses 2022; 14:v14030631. [PMID: 35337038 PMCID: PMC8954079 DOI: 10.3390/v14030631] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/04/2022] [Accepted: 03/09/2022] [Indexed: 11/16/2022] Open
Abstract
Infectious salmon anemia virus (ISAV) is the etiological agent of infectious salmon anemia. It belongs to the genus isavirus, one of the genera of the Orthomyxoviridae family, as does Influenzavirus A. The ISAV genome comprises eight negative-sense single-stranded RNA segments that code for at least 10 proteins. Although some ISAV strains can reach 100% mortality rates, the factors that determine isavirus infectivity remain unknown. However, some studies suggest that segments 5 and 6 are responsible for the different degrees of virulence and infectivity among ISAV subtypes, unlike the influenza A virus, where most segments are involved in the virus infectivity. In this work, synthetic reassortant viruses for the eight segments of ISAV were generated by reverse genetics, combining a highly virulent virus, ISAV 752_09 (HPR7b), and an avirulent strain, SK779/06 (HPR0). We characterized the rescued viruses and their capacity to replicate and infect different cell lines, produce plaques in ASK cells, and their ability to induce and modulate the cellular immune response in vitro. Our results show that the majority of ISAV segments are involved in at least one of the analyzed characteristics, segment 5 being one of the most important, allowing HPR0 viruses, among other things, to produce plaques and replicate in CHSE-214 cells. We determined that segments 5 and 6 participate in different stages of the viral cycle, and their compatibility is critical for viral infection. Additionally, we demonstrated that segment 2 can modulate the cellular immune response. Our results indicate a high degree of genetic compatibility between the genomic segments of HPR7b and HPR0, representing a latent risk of reassortant that would give rise to a new virus with an unknown phenotype.
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Affiliation(s)
- Matías Cárdenas
- Molecular Virology and Pathogen Control Laboratory, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago 9170022, Chile; (M.C.); (S.M.); (Y.V.-M.)
- Poultry Diagnostic and Research Center, Department of Population Health, University of Georgia, Athens, GE 30602, USA;
| | - Sofía Michelson
- Molecular Virology and Pathogen Control Laboratory, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago 9170022, Chile; (M.C.); (S.M.); (Y.V.-M.)
| | - Daniel R. Pérez
- Poultry Diagnostic and Research Center, Department of Population Health, University of Georgia, Athens, GE 30602, USA;
| | - Margarita Montoya
- Cell Biochemistry Laboratory, Department of Biology, Faculty of Chemistry and Biology, University of Santiago, Santiago 9170022, Chile;
| | - Jorge Toledo
- Biotechnology and Biopharmaceutical Laboratory, Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción 4070386, Chile;
| | - Yesseny Vásquez-Martínez
- Molecular Virology and Pathogen Control Laboratory, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago 9170022, Chile; (M.C.); (S.M.); (Y.V.-M.)
- Programa Centro de Investigaciones Biomédicas Aplicadas, Escuela de Medicina, Facultad de Ciencias Médicas, Universidad de Santiago, Santiago 9170022, Chile
| | - Marcelo Cortez-San Martin
- Molecular Virology and Pathogen Control Laboratory, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago 9170022, Chile; (M.C.); (S.M.); (Y.V.-M.)
- Correspondence:
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