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Polinski MP, Lifgren D, Clayton RD, Warg JV, Pietrak MR, Peterson BC. Nonvirulent Infectious Salmon Anemia Virus (ISAV-HPR0) Not Detectable in Eggs or Progeny of Infected Captive Atlantic Salmon Brood. Viruses 2024; 16:1288. [PMID: 39205262 PMCID: PMC11359038 DOI: 10.3390/v16081288] [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] [Received: 07/17/2024] [Revised: 08/08/2024] [Accepted: 08/12/2024] [Indexed: 09/04/2024] Open
Abstract
The potential for infectious salmon anemia virus (ISAV)-an internationally regulated pathogen of salmon-to transmit vertically from parent to offspring is currently unclear. While the highly virulent ISAV phenotype known as ISAV-HPRΔ has been observed intra-ova, evidence for vertical transmission of the avirulent ISAV phenotype known as ISAV-HPR0 is lacking. In this study, we identified ISAV-HPR0-infected Atlantic salmon broodstock during spawning within a government research recirculating aquaculture facility using qPCR. Eggs and milt from infected brood were used to initiate 16 unique family dam-sire crosses from which 29-60 fertilized eggs per cross were screened for ISAV using qPCR (limit of detection ~100 virus genome copies/egg). A portion of eggs (~300) from one family cross was hatched and further reared in biosecure containment and periodically screened for ISAV by gill clipping over a 2-year period. ISAV was not detected in any of the 781 eggs screened from 16 family crosses generated by infected brood, nor in 870 gill clips periodically sampled from the single-family cohort raised for 2 years in biocontainment. Based on these findings, we conclude that ISAV-HPR0 has a limited likelihood for vertical parent-to-offspring transmission in cultured Atlantic salmon.
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Affiliation(s)
- Mark P. Polinski
- National Cold Water Marine Aquaculture Center, U.S. Department of Agriculture–Agricultural Research Service, Franklin, ME 04634, USA; (D.L.); (M.R.P.); (B.C.P.)
| | - Demitri Lifgren
- National Cold Water Marine Aquaculture Center, U.S. Department of Agriculture–Agricultural Research Service, Franklin, ME 04634, USA; (D.L.); (M.R.P.); (B.C.P.)
| | - Richard D. Clayton
- National Veterinary Services Laboratories, U.S. Department of Agriculture–Animal and Plant Health Inspection Service, Ames, IA 50010, USA; (R.D.C.); (J.V.W.)
| | - Janet V. Warg
- National Veterinary Services Laboratories, U.S. Department of Agriculture–Animal and Plant Health Inspection Service, Ames, IA 50010, USA; (R.D.C.); (J.V.W.)
| | - Michael R. Pietrak
- National Cold Water Marine Aquaculture Center, U.S. Department of Agriculture–Agricultural Research Service, Franklin, ME 04634, USA; (D.L.); (M.R.P.); (B.C.P.)
| | - Brian C. Peterson
- National Cold Water Marine Aquaculture Center, U.S. Department of Agriculture–Agricultural Research Service, Franklin, ME 04634, USA; (D.L.); (M.R.P.); (B.C.P.)
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Eckstrand CD, Torrevillas BK, Wolking RM, Bradway DS, Warg JV, Clayton RD, Williams LB, Pessier AP, Reno JL, McMenamin-Snekvik KM, Thompson J, Baszler T, Snekvik KR. Investigation of laboratory methods for characterization of aquatic viruses in fish infected experimentally with infectious salmon anemia virus. J Vet Diagn Invest 2024; 36:319-328. [PMID: 37203453 PMCID: PMC11110770 DOI: 10.1177/10406387231173332] [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: 05/20/2023] Open
Abstract
Rapid growth in aquaculture has resulted in high-density production systems in ecologically and geographically novel conditions in which the emergence of diseases is inevitable. Well-characterized methods for detection and surveillance of infectious diseases are vital for rapid identification, response, and recovery to protect economic and food security. We implemented a proof-of-concept approach for virus detection using a known high-consequence fish pathogen, infectious salmon anemia virus (ISAV), as the archetypal pathogen. In fish infected with ISAV, we integrated histopathology, virus isolation, whole-genome sequencing (WGS), electron microscopy (EM), in situ hybridization (ISH), and reverse transcription real-time PCR (RT-rtPCR). Fresh-frozen and formalin-fixed tissues were collected from virus-infected, control, and sham-infected Atlantic salmon (Salmo salar). Microscopic differences were not evident between uninfected and infected fish. Viral cytopathic effect was observed in cell cultures inoculated with fresh-frozen tissue homogenates from 3 of 3 ISAV-infected and 0 of 4 uninfected or sham-infected fish. The ISAV genome was detected by shotgun metagenomics in RNA extracted from the medium from 3 of 3 inoculated cell cultures, 3 of 3 infected fish, and 0 of 4 uninfected or sham-infected fish, yielding sufficient coverage for de novo assembly. An ISH probe against ISAV revealed ISAV genome in multiple organs, with abundance in renal hematopoietic tissue. Virus was detected by RT-rtPCR in gill, heart, kidney, liver, and spleen. EM and metagenomic WGS from tissues were challenging and unsuccessful. Our proof-of-concept methodology has promise for detection and characterization of unknown aquatic pathogens and also highlights some associated methodology challenges that require additional investigation.
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Affiliation(s)
- Chrissy D. Eckstrand
- Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA, USA
| | - Brandi K. Torrevillas
- Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA, USA
| | - Rebecca M. Wolking
- Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA, USA
| | - Daniel S. Bradway
- Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA, USA
| | - Janet V. Warg
- National Veterinary Services Laboratories, U.S. Department of Agriculture, Ames, IA, USA
| | - Richard D. Clayton
- National Veterinary Services Laboratories, U.S. Department of Agriculture, Ames, IA, USA
| | - Laura B. Williams
- Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA, USA
| | - Allan P. Pessier
- Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA, USA
| | - Joetta Lynn Reno
- Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA, USA
| | | | - Jim Thompson
- Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA, USA
| | - Timothy Baszler
- Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA, USA
| | - Kevin R. Snekvik
- Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA, USA
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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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Sommers P, Chatterjee A, Varsani A, Trubl G. Integrating Viral Metagenomics into an Ecological Framework. Annu Rev Virol 2021; 8:133-158. [PMID: 34033501 DOI: 10.1146/annurev-virology-010421-053015] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Viral metagenomics has expanded our knowledge of the ecology of uncultured viruses, within both environmental (e.g., terrestrial and aquatic) and host-associated (e.g., plants and animals, including humans) contexts. Here, we emphasize the implementation of an ecological framework in viral metagenomic studies to address questions in virology rarely considered ecological, which can change our perception of viruses and how they interact with their surroundings. An ecological framework explicitly considers diverse variants of viruses in populations that make up communities of interacting viruses, with ecosystem-level effects. It provides a structure for the study of the diversity, distributions, dynamics, and interactions of viruses with one another, hosts, and the ecosystem, including interactions with abiotic factors. An ecological framework in viral metagenomics stands poised to broadly expand our knowledge in basic and applied virology. We highlight specific fundamental research needs to capitalize on its potential and advance the field. Expected final online publication date for the Annual Review of Virology, Volume 8 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Pacifica Sommers
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, Colorado 80309, USA.,These authors contributed equally to this article
| | - Anushila Chatterjee
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, Colorado 80309, USA.,These authors contributed equally to this article
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA; .,Structural Biology Research Unit, Department of Integrative Biomedical Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Gareth Trubl
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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Teffer AK, Carr J, Tabata A, Schulze A, Bradbury I, Deschamps D, Gillis CA, Brunsdon EB, Mordecai G, Miller KM. A molecular assessment of infectious agents carried by Atlantic salmon at sea and in three eastern Canadian rivers, including aquaculture escapees and North American and European origin wild stocks. Facets (Ott) 2020. [DOI: 10.1139/facets-2019-0048] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Infectious agents are key components of animal ecology and drivers of host population dynamics. Knowledge of their diversity and transmission in the wild is necessary for the management and conservation of host species like Atlantic salmon ( Salmo salar). Although pathogen exchange can occur throughout the salmon life cycle, evidence is lacking to support transmission during population mixing at sea or between farmed and wild salmon due to aquaculture exposure. We tested these hypotheses using a molecular approach that identified infectious agents and transmission potential among sub-adult Atlantic salmon at marine feeding areas and adults in three eastern Canadian rivers with varying aquaculture influence. We used high-throughput qPCR to quantify infection profiles and next generation sequencing to measure genomic variation among viral isolates. We identified 14 agents, including five not yet described as occurring in Eastern Canada. Phylogenetic analysis of piscine orthoreovirus showed homology between isolates from European and North American origin fish at sea, supporting the hypothesis of intercontinental transmission. We found no evidence to support aquaculture influence on wild adult infections, which varied relative to environmental conditions, life stage, and host origin. Our findings identify research opportunities regarding pathogen transmission and biological significance for wild Atlantic salmon populations.
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Affiliation(s)
- Amy K. Teffer
- Department of Forest and Conservation Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Jonathan Carr
- Atlantic Salmon Federation, Chamcook, NB E5B 3A9, Canada
| | - Amy Tabata
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC V9T 6N7, Canada
| | - Angela Schulze
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC V9T 6N7, Canada
| | - Ian Bradbury
- Salmonids Section, Fisheries and Oceans Canada, St. John’s, NF A1C 5X1, Canada
| | - Denise Deschamps
- Ministère des Forêts, de la Faune et des Parcs du Québec, Direction de l’expertise sur la faune aquatique, Quebec, QC G1S 4X4, Canada
| | | | | | - Gideon Mordecai
- Department of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Kristina M. Miller
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC V9T 6N7, Canada
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