Wild and farmed salmon (Salmo salar) as reservoirs for infectious salmon anaemia virus, and the importance of horizontal- and vertical transmission.
The infectious salmon anaemia virus (ISAV) is an important pathogen on farmed salmon in Europe. The virus occurs as low- and high virulent variants where the former seem to be a continuous source of new high virulent ISAV. The latter are controlled in Norway by stamping out infected populations whil...
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ftdoajarticles:oai:doaj.org/article:bad7c204c3ab4922bd1e9be182a83d39 2023-05-15T18:09:50+02:00 Wild and farmed salmon (Salmo salar) as reservoirs for infectious salmon anaemia virus, and the importance of horizontal- and vertical transmission. Are Nylund Jarle Brattespe Heidrun Plarre Martha Kambestad Marius Karlsen 2019-01-01T00:00:00Z https://doi.org/10.1371/journal.pone.0215478 https://doaj.org/article/bad7c204c3ab4922bd1e9be182a83d39 EN eng Public Library of Science (PLoS) https://doi.org/10.1371/journal.pone.0215478 https://doaj.org/toc/1932-6203 1932-6203 doi:10.1371/journal.pone.0215478 https://doaj.org/article/bad7c204c3ab4922bd1e9be182a83d39 PLoS ONE, Vol 14, Iss 4, p e0215478 (2019) Medicine R Science Q article 2019 ftdoajarticles https://doi.org/10.1371/journal.pone.0215478 2022-12-31T13:17:42Z The infectious salmon anaemia virus (ISAV) is an important pathogen on farmed salmon in Europe. The virus occurs as low- and high virulent variants where the former seem to be a continuous source of new high virulent ISAV. The latter are controlled in Norway by stamping out infected populations while the former are spreading uncontrolled among farmed salmon. Evidence of vertical transmission has been presented, but there is still an ongoing discussion of the importance of circulation of ISAV via salmon brood fish. The only known wild reservoirs are in trout (Salmo trutta) and salmon (Salmo salar). This study provides the first ISAV sequences from wild salmonids in Norway and evaluates the importance of this reservoir with respect to outbreaks of ISA among farmed salmon. Phylogenetic analyses of the surface protein hemagglutinin-esterase gene from nearly all available ISAV from Norway, Faeroe Islands, Scotland, Chile and wild salmonids in Norway show that they group into four major clades. Including virulent variants in the analysis show that they belong in the same four clades supporting the hypothesis that there is a high frequency of transition from low to high virulent variants in farmed populations of salmon. There is little support for a hypothesis suggesting that the wild salmonids feed the virus into farmed populations. This study give support to earlier studies that have documented local horizontal transmission of high virulent ISAV, but the importance of transition from low- to high virulent variants has been underestimated. Evidence of vertical transmission and long distance spreading of ISAV via movement of embryos and smolt is presented. We recommend that the industry focus on removing the low virulent ISAV from the brood fish and that ISAV-free brood fish salmon are kept in closed containment systems (CCS). Article in Journal/Newspaper Salmo salar Directory of Open Access Journals: DOAJ Articles Norway PLOS ONE 14 4 e0215478 |
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Directory of Open Access Journals: DOAJ Articles |
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English |
topic |
Medicine R Science Q |
spellingShingle |
Medicine R Science Q Are Nylund Jarle Brattespe Heidrun Plarre Martha Kambestad Marius Karlsen Wild and farmed salmon (Salmo salar) as reservoirs for infectious salmon anaemia virus, and the importance of horizontal- and vertical transmission. |
topic_facet |
Medicine R Science Q |
description |
The infectious salmon anaemia virus (ISAV) is an important pathogen on farmed salmon in Europe. The virus occurs as low- and high virulent variants where the former seem to be a continuous source of new high virulent ISAV. The latter are controlled in Norway by stamping out infected populations while the former are spreading uncontrolled among farmed salmon. Evidence of vertical transmission has been presented, but there is still an ongoing discussion of the importance of circulation of ISAV via salmon brood fish. The only known wild reservoirs are in trout (Salmo trutta) and salmon (Salmo salar). This study provides the first ISAV sequences from wild salmonids in Norway and evaluates the importance of this reservoir with respect to outbreaks of ISA among farmed salmon. Phylogenetic analyses of the surface protein hemagglutinin-esterase gene from nearly all available ISAV from Norway, Faeroe Islands, Scotland, Chile and wild salmonids in Norway show that they group into four major clades. Including virulent variants in the analysis show that they belong in the same four clades supporting the hypothesis that there is a high frequency of transition from low to high virulent variants in farmed populations of salmon. There is little support for a hypothesis suggesting that the wild salmonids feed the virus into farmed populations. This study give support to earlier studies that have documented local horizontal transmission of high virulent ISAV, but the importance of transition from low- to high virulent variants has been underestimated. Evidence of vertical transmission and long distance spreading of ISAV via movement of embryos and smolt is presented. We recommend that the industry focus on removing the low virulent ISAV from the brood fish and that ISAV-free brood fish salmon are kept in closed containment systems (CCS). |
format |
Article in Journal/Newspaper |
author |
Are Nylund Jarle Brattespe Heidrun Plarre Martha Kambestad Marius Karlsen |
author_facet |
Are Nylund Jarle Brattespe Heidrun Plarre Martha Kambestad Marius Karlsen |
author_sort |
Are Nylund |
title |
Wild and farmed salmon (Salmo salar) as reservoirs for infectious salmon anaemia virus, and the importance of horizontal- and vertical transmission. |
title_short |
Wild and farmed salmon (Salmo salar) as reservoirs for infectious salmon anaemia virus, and the importance of horizontal- and vertical transmission. |
title_full |
Wild and farmed salmon (Salmo salar) as reservoirs for infectious salmon anaemia virus, and the importance of horizontal- and vertical transmission. |
title_fullStr |
Wild and farmed salmon (Salmo salar) as reservoirs for infectious salmon anaemia virus, and the importance of horizontal- and vertical transmission. |
title_full_unstemmed |
Wild and farmed salmon (Salmo salar) as reservoirs for infectious salmon anaemia virus, and the importance of horizontal- and vertical transmission. |
title_sort |
wild and farmed salmon (salmo salar) as reservoirs for infectious salmon anaemia virus, and the importance of horizontal- and vertical transmission. |
publisher |
Public Library of Science (PLoS) |
publishDate |
2019 |
url |
https://doi.org/10.1371/journal.pone.0215478 https://doaj.org/article/bad7c204c3ab4922bd1e9be182a83d39 |
geographic |
Norway |
geographic_facet |
Norway |
genre |
Salmo salar |
genre_facet |
Salmo salar |
op_source |
PLoS ONE, Vol 14, Iss 4, p e0215478 (2019) |
op_relation |
https://doi.org/10.1371/journal.pone.0215478 https://doaj.org/toc/1932-6203 1932-6203 doi:10.1371/journal.pone.0215478 https://doaj.org/article/bad7c204c3ab4922bd1e9be182a83d39 |
op_doi |
https://doi.org/10.1371/journal.pone.0215478 |
container_title |
PLOS ONE |
container_volume |
14 |
container_issue |
4 |
container_start_page |
e0215478 |
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