Epidemiological aspects of infectious salmon anemia
Infectious salmon anemia is an orthomyxyviral disease posing a serious challenge to the aquaculture of atlantic salmon (Salmo salar). The virus causes severe disease resulting in high moratlity and significant costs to the industry. Several factors, natural and human induced, have been studied as to...
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| Formato: | M2 |
| Lenguaje: | Inglés sueco |
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SLU/Dept. of Biomedical Sciences and Veterinary Public Health (until 231231)
2019
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| Materias: |
| _version_ | 1855572412984197120 |
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| author | Mård, Karl |
| author_browse | Mård, Karl |
| author_facet | Mård, Karl |
| author_sort | Mård, Karl |
| collection | Epsilon Archive for Student Projects |
| description | Infectious salmon anemia is an orthomyxyviral disease posing a serious challenge to the aquaculture of atlantic salmon (Salmo salar). The virus causes severe disease resulting in high moratlity and significant costs to the industry. Several factors, natural and human induced, have been studied as to their proposed role in the spread of the ISA-virus and its impact on salmon farming. Spread by equipment and fish movement is well substantiated. Equally substantial is the impact of geographical relations between farms, processing boat lanes, processing plants and other farms. However, the evidence for the proposed direct waterborne spread, that this often is attributed to, is inconclusive and perhaps even negligible in a natural setting. This is because the virion’s ability to survive in biologically active and UV-radiated water might not allow waterborne spread over long distances. There is also evidence suggesting that the general health of a population of salmon affects the risk of outbreaks and that immunosuppression due to chronic stress induced by high stocking densities, routine vaccination via injection and major sea lice infestation might increase susceptibility to the disease. Much like mammalian and avian influenza (other orthomyxoviral agents) there is a substantial difference in the pathogenic potential between different strains, with some producing no clinical disease while others are deadly due to minor changes in the viral genome. The non-pathogenic strains, causing no clinical disease, was in one study found to be highly prevalent and have been shown to be potential ancestors to pathogenic strains, and as such might be central to the disease’s epidemiology. Wild salmonids have been shown to be potential symptomless carriers of the virus and sea lice have under experimental conditions acted as mechanical vectors; suggesting a complex epidemiology that might be dependent on the combined prevalence of pathogenic and non-pathogenic strains as well as an unknown role of natural reservoirs and vectors in the spread of the disease. |
| format | M2 |
| id | RepoSLU14463 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2019 |
| publishDateSort | 2019 |
| publisher | SLU/Dept. of Biomedical Sciences and Veterinary Public Health (until 231231) |
| publisherStr | SLU/Dept. of Biomedical Sciences and Veterinary Public Health (until 231231) |
| record_format | eprints |
| spelling | RepoSLU144632019-05-11T01:00:36Z Epidemiological aspects of infectious salmon anemia Epidemiologiska aspekter av infektiös laxanemi Mård, Karl Infektiös laxanemi ILA epidemiologi Infectious salmon anemia is an orthomyxyviral disease posing a serious challenge to the aquaculture of atlantic salmon (Salmo salar). The virus causes severe disease resulting in high moratlity and significant costs to the industry. Several factors, natural and human induced, have been studied as to their proposed role in the spread of the ISA-virus and its impact on salmon farming. Spread by equipment and fish movement is well substantiated. Equally substantial is the impact of geographical relations between farms, processing boat lanes, processing plants and other farms. However, the evidence for the proposed direct waterborne spread, that this often is attributed to, is inconclusive and perhaps even negligible in a natural setting. This is because the virion’s ability to survive in biologically active and UV-radiated water might not allow waterborne spread over long distances. There is also evidence suggesting that the general health of a population of salmon affects the risk of outbreaks and that immunosuppression due to chronic stress induced by high stocking densities, routine vaccination via injection and major sea lice infestation might increase susceptibility to the disease. Much like mammalian and avian influenza (other orthomyxoviral agents) there is a substantial difference in the pathogenic potential between different strains, with some producing no clinical disease while others are deadly due to minor changes in the viral genome. The non-pathogenic strains, causing no clinical disease, was in one study found to be highly prevalent and have been shown to be potential ancestors to pathogenic strains, and as such might be central to the disease’s epidemiology. Wild salmonids have been shown to be potential symptomless carriers of the virus and sea lice have under experimental conditions acted as mechanical vectors; suggesting a complex epidemiology that might be dependent on the combined prevalence of pathogenic and non-pathogenic strains as well as an unknown role of natural reservoirs and vectors in the spread of the disease. Infektiös laxanemi (ILA) är ett orthomyxovirus som representerar en betydande utmaning för kommersiell laxodling. Viruset orsakar allvarlig sjukdom hos atlantisk lax (Salmo salar) som ofta resulterar i hög dödlighet och stora kostnader för industrin. Flera faktorer, både naturliga och relaterade till mänsklig aktivitet, har studerats utefter deras roll i sjukdomens epidemiologi. Spridning via utrustning och fisktransporter är väldokumenterat och har stort stöd i litteraturen. Ett liknande stöd finns även för den geografiska relationen mellan odlingar, processeringsbåtar, processeringsstationer och andra odlingar. Stödet för den direkta spridningen via vatten som detta ofta associeras med är mindre entydigt, möjligen till och med negligerbart under naturliga förhållande. Det finns evidens som tyder på att den generella hälsostatusen i en odling påverkar risken för ILA-utbrott och att immunosuppression orsakat av kronisk stress till följd av hög beläggningsgrad, rutinmässig vaccination via injektion och betydande infestation av laxlus ökar mottagligheten för sjukdomen. I stil med influensa hos däggdjur och fåglar (andra orthomyxovirala agens) finns stora skillnader i virulens mellan olika stammar av viruset till följd av mindre skillnader i det virala genomet; vissa producerar ingen klinisk sjukdom medan andra leder till hög mortalitet. De lågpatogena stammarna visades i en studie ha en hög prevalens och anses vara en potentiell föregångare till högpatogena varianter, vilket kan tyda på att de har en viktig roll i sjukdomens spridning. Vilda laxfiskar har visats vara potentiella symptomfria bärare av viruset och likaså har laxlus under experimentella förhållanden agerat som mekaniska vektorer. Detta tyder på en komplex epidemiologi med inverkan av den kombinerade prevalensen av hög- och lågpatogena stammar tillsammans med en okänd roll av naturliga reservoarer och vektor. SLU/Dept. of Biomedical Sciences and Veterinary Public Health (until 231231) 2019 M2 eng swe https://stud.epsilon.slu.se/14463/ |
| spellingShingle | Infektiös laxanemi ILA epidemiologi Mård, Karl Epidemiological aspects of infectious salmon anemia |
| title | Epidemiological aspects of infectious salmon anemia |
| title_full | Epidemiological aspects of infectious salmon anemia |
| title_fullStr | Epidemiological aspects of infectious salmon anemia |
| title_full_unstemmed | Epidemiological aspects of infectious salmon anemia |
| title_short | Epidemiological aspects of infectious salmon anemia |
| title_sort | epidemiological aspects of infectious salmon anemia |
| topic | Infektiös laxanemi ILA epidemiologi |