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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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Gautam M, Hammell KL, Burnley H, O'Brien N, Whelan D, Thakur KK. Description of spatiotemporal patterns of infectious salmon anemia virus (ISAV) detections in marine Atlantic Salmon farms in Newfoundland and Labrador. JOURNAL OF AQUATIC ANIMAL HEALTH 2023; 35:296-307. [PMID: 38124493 DOI: 10.1002/aah.10205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 09/23/2023] [Accepted: 09/25/2023] [Indexed: 12/23/2023]
Abstract
OBJECTIVE The objectives of this study were to describe spatiotemporal patterns of infectious salmon anemia virus (ISAV) detections in marine salmonid production sites in the province of Newfoundland and Labrador in Canada. METHODS Infectious salmon anemia virus surveillance data between 2012 and 2020 from the province of Newfoundland and Labrador were used. Data comprised a total of 94 sampling events from 20 Atlantic Salmon Salmo salar production sites in which ISAV was detected. Using linear regression models, factors influencing time to detection (days from stocking to first ISAV detection) and time to depopulation (days from first detection to production site depopulation) were investigated. RESULT Based on 28 unique cases, site-level annual incidence risk of ISAV detection ranged from 3% to 29%. The proportion of ISAV detection by PCR in fish samples ranged from 2% to 45% annually. Overall, ISAV variants from the European clade were more common than variants from the North American clade. The type of ISAV clade, detections of ISAV in nearest production sites based on seaway distances, and year of infectious salmon anemia cases were not associated with time to first ISAV detection. Time to depopulation for sites infected with the ISAV-HPRΔ variant was not associated with ISAV North American or European clades. CONCLUSION Our results contribute to the further understanding of the changing dynamics of infectious salmon anemia detections in Newfoundland and Labrador since its first detection in 2012 and will likely assist in the design of improved disease surveillance and control programs in the province.
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Affiliation(s)
- Milan Gautam
- Centre for Veterinary Epidemiological Research and 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 and Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Holly Burnley
- Centre for Veterinary Epidemiological Research and Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Nicole O'Brien
- Department of Fisheries, Forestry and Agriculture, Aquatic Animal Health Division, St. John's, Newfoundland and Labrador, Canada
| | - Daryl Whelan
- Department of Fisheries, Forestry and Agriculture, Aquatic Animal Health Division, St. John's, Newfoundland and Labrador, Canada
| | - Krishna Kumar Thakur
- Centre for Veterinary Epidemiological Research and Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
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Zhong L, Carvalho LA, Gao S, Whyte SK, Purcell SL, Fast MD, Cai W. Transcriptome analysis revealed immune responses in the kidney of Atlantic salmon (Salmo salar) co-infected with sea lice (Lepeophtheirus salmonis) and infectious salmon anemia virus. FISH & SHELLFISH IMMUNOLOGY 2023; 143:109210. [PMID: 37951318 DOI: 10.1016/j.fsi.2023.109210] [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: 06/27/2023] [Revised: 10/17/2023] [Accepted: 11/02/2023] [Indexed: 11/13/2023]
Abstract
Sea lice (Lepeophtheirus salmonis) and infectious salmon anemia virus (ISAv) are two of the most important pathogens in Atlantic salmon (Salmo salar) farming and typically cause substantial economic losses to the industry. However, the immune interactions between hosts and these pathogens are still unclear, especially in the scenario of co-infection. In this study, we artificially infected Atlantic salmon with sea lice and ISAv, and investigated the gene expression patterns of Atlantic salmon head kidneys in response to both lice only and co-infection with lice and ISAv by transcriptomic analysis. The challenge experiment indicated that co-infection resulted in a cumulative mortality rate of 47.8 %, while no mortality was observed in the lice alone infection. We identified 240 differentially expressed genes (DEGs) under the lice alone infection, of which 185 were down-regulated and 55 were up-regulated, while a total of 994 DEGs were identified in the co-infection, of which 206 were down-regulated and 788 were significantly up-regulated. The pathway enrichment analysis revealed that single-infection significantly suppressed the innate immune system (e.g., the complement system), whereas co-infection induced a strong immune response, leading to the activation of immune-related signaling pathways such as Toll-like receptors and NOD-like receptors pathways, as well as significant upregulation of genes related to the activation of interferon and MH class I protein complex. Our results provide the first global transcriptomic study of gene expression in the Atlantic salmon head kidney in response to co-infection with sea lice and ISAv, and provided the baseline knowledge for understanding the immune responses during co-infection.
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Affiliation(s)
- Liang Zhong
- Department of Infectious Diseases and Public Health, and State Key Lab of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Laura A Carvalho
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3, Canada
| | - Shengnan Gao
- Department of Infectious Diseases and Public Health, and State Key Lab of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Shona K Whyte
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3, Canada
| | - Sara L Purcell
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3, Canada
| | - Mark D Fast
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3, Canada.
| | - Wenlong Cai
- Department of Infectious Diseases and Public Health, and State Key Lab of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong; Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3, Canada.
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