No influence of oxygen levels on pathogenesis and virus shedding in Salmonid alphavirus (SAV)-challenged Atlantic salmon (Salmo salar L.)
Background For more than three decades, diseases caused by salmonid alphaviruses (SAV) have become a major problem of increasing economic importance in the European fish-farming industry. However, experimental infection trials with SAV result in low or no mortality i.e very different from most field...
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ftunivbergen:oai:bora.uib.no:1956/4664 2023-05-15T15:32:58+02:00 No influence of oxygen levels on pathogenesis and virus shedding in Salmonid alphavirus (SAV)-challenged Atlantic salmon (Salmo salar L.) Andersen, Linda Hodneland, Kjartan Nylund, Are 2010-08-21 application/pdf text/xml http://hdl.handle.net/1956/4664 https://doi.org/10.1186/1743-422x-7-198 eng eng BioMed Central urn:issn:1743-422X http://hdl.handle.net/1956/4664 https://doi.org/10.1186/1743-422x-7-198 cristin:529577 Attribution CC BY http://creativecommons.org/licenses/by/2.0 Andersen et al. Copyright 2010 Andersen et al; licensee BioMed Central Ltd. VDP::Mathematics and natural science: 400 Peer reviewed Journal article 2010 ftunivbergen https://doi.org/10.1186/1743-422x-7-198 2023-03-14T17:39:28Z Background For more than three decades, diseases caused by salmonid alphaviruses (SAV) have become a major problem of increasing economic importance in the European fish-farming industry. However, experimental infection trials with SAV result in low or no mortality i.e very different from most field outbreaks of pancreas disease (PD). This probably reflects the difficulties in reproducing complex biotic and abiotic field conditions in the laboratory. In this study we looked at the relationship between SAV-infection in salmon and sub-lethal environmental hypoxia as a result of reduced flow-through in tank systems. Results The experiment demonstrated that constant reduced oxygen levels (60-65% oxygen saturation: 6.5-7.0 mg/L) did not significantly increase the severity or the progress of pancreas disease (PD). These conclusions are based upon assessments of a semi-quantitative histopathological lesion score system, morbidities/mortalities, and levels of SAV RNA in tissues and water (measured by 1 MDS electropositive virus filters and downstream real-time RT-PCR). Furthermore, we demonstrate that the fish population shed detectable levels of the virus into the surrounding water during viraemia; 4-13 days after i.p. infection, and prior to appearance of severe lesions in heart (21-35 dpi). After this period, viral RNA from SAV could not be detected in water samples although still present in tissues (gills and hearts) at lasting low levels. Lesions could be seen in exocrine pancreas at 7-21 days post infection, but no muscle lesions were seen. Conclusions In our study, experimentally induced hypoxia failed to explain the discrepancy between the severities reported from field outbreaks of SAV-disease and experimental infections. Reduction of oxygen levels to constant suboptimal levels had no effect on the severity of lesions caused by SAV-infection or the progress of the disease. Furthermore, we present a modified VIRADEL method which can be used to detect virus in water and to supplement experimental infection trials ... Article in Journal/Newspaper Atlantic salmon Salmo salar University of Bergen: Bergen Open Research Archive (BORA-UiB) Sav’ ENVELOPE(156.400,156.400,68.817,68.817) Virology Journal 7 1 |
institution |
Open Polar |
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University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
topic |
VDP::Mathematics and natural science: 400 |
spellingShingle |
VDP::Mathematics and natural science: 400 Andersen, Linda Hodneland, Kjartan Nylund, Are No influence of oxygen levels on pathogenesis and virus shedding in Salmonid alphavirus (SAV)-challenged Atlantic salmon (Salmo salar L.) |
topic_facet |
VDP::Mathematics and natural science: 400 |
description |
Background For more than three decades, diseases caused by salmonid alphaviruses (SAV) have become a major problem of increasing economic importance in the European fish-farming industry. However, experimental infection trials with SAV result in low or no mortality i.e very different from most field outbreaks of pancreas disease (PD). This probably reflects the difficulties in reproducing complex biotic and abiotic field conditions in the laboratory. In this study we looked at the relationship between SAV-infection in salmon and sub-lethal environmental hypoxia as a result of reduced flow-through in tank systems. Results The experiment demonstrated that constant reduced oxygen levels (60-65% oxygen saturation: 6.5-7.0 mg/L) did not significantly increase the severity or the progress of pancreas disease (PD). These conclusions are based upon assessments of a semi-quantitative histopathological lesion score system, morbidities/mortalities, and levels of SAV RNA in tissues and water (measured by 1 MDS electropositive virus filters and downstream real-time RT-PCR). Furthermore, we demonstrate that the fish population shed detectable levels of the virus into the surrounding water during viraemia; 4-13 days after i.p. infection, and prior to appearance of severe lesions in heart (21-35 dpi). After this period, viral RNA from SAV could not be detected in water samples although still present in tissues (gills and hearts) at lasting low levels. Lesions could be seen in exocrine pancreas at 7-21 days post infection, but no muscle lesions were seen. Conclusions In our study, experimentally induced hypoxia failed to explain the discrepancy between the severities reported from field outbreaks of SAV-disease and experimental infections. Reduction of oxygen levels to constant suboptimal levels had no effect on the severity of lesions caused by SAV-infection or the progress of the disease. Furthermore, we present a modified VIRADEL method which can be used to detect virus in water and to supplement experimental infection trials ... |
format |
Article in Journal/Newspaper |
author |
Andersen, Linda Hodneland, Kjartan Nylund, Are |
author_facet |
Andersen, Linda Hodneland, Kjartan Nylund, Are |
author_sort |
Andersen, Linda |
title |
No influence of oxygen levels on pathogenesis and virus shedding in Salmonid alphavirus (SAV)-challenged Atlantic salmon (Salmo salar L.) |
title_short |
No influence of oxygen levels on pathogenesis and virus shedding in Salmonid alphavirus (SAV)-challenged Atlantic salmon (Salmo salar L.) |
title_full |
No influence of oxygen levels on pathogenesis and virus shedding in Salmonid alphavirus (SAV)-challenged Atlantic salmon (Salmo salar L.) |
title_fullStr |
No influence of oxygen levels on pathogenesis and virus shedding in Salmonid alphavirus (SAV)-challenged Atlantic salmon (Salmo salar L.) |
title_full_unstemmed |
No influence of oxygen levels on pathogenesis and virus shedding in Salmonid alphavirus (SAV)-challenged Atlantic salmon (Salmo salar L.) |
title_sort |
no influence of oxygen levels on pathogenesis and virus shedding in salmonid alphavirus (sav)-challenged atlantic salmon (salmo salar l.) |
publisher |
BioMed Central |
publishDate |
2010 |
url |
http://hdl.handle.net/1956/4664 https://doi.org/10.1186/1743-422x-7-198 |
long_lat |
ENVELOPE(156.400,156.400,68.817,68.817) |
geographic |
Sav’ |
geographic_facet |
Sav’ |
genre |
Atlantic salmon Salmo salar |
genre_facet |
Atlantic salmon Salmo salar |
op_relation |
urn:issn:1743-422X http://hdl.handle.net/1956/4664 https://doi.org/10.1186/1743-422x-7-198 cristin:529577 |
op_rights |
Attribution CC BY http://creativecommons.org/licenses/by/2.0 Andersen et al. Copyright 2010 Andersen et al; licensee BioMed Central Ltd. |
op_doi |
https://doi.org/10.1186/1743-422x-7-198 |
container_title |
Virology Journal |
container_volume |
7 |
container_issue |
1 |
_version_ |
1766363438736474112 |