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dc.contributor.authorKunttu, Heidi
dc.date.accessioned2010-05-03T06:34:41Z
dc.date.available2010-05-03T06:34:41Z
dc.date.issued2010
dc.identifier.isbn978-951-39-3867-3
dc.identifier.otheroai:jykdok.linneanet.fi:1128636
dc.identifier.urihttps://jyx.jyu.fi/handle/123456789/23323
dc.description.abstractFlavobacterium columnare is a bacterial pathogen of fresh water fish causing lethal columnaris disease worldwide. At Finnish fish farms, columnaris disease has occurred since the early 1980s, and is a serious problem in salmonid farming in Finland. Currently, the only effective treatment is with antibiotics. Factors related to the pathogenicity of F. columnare, transmission of columnaris disease and the immunity of salmonids to columnaris infections are poorly known. F. columnare strains isolated from Finnish fish farms were characterized geno- and phenotypically, virulence and transmission experiments were conducted, and the efficacy of two immunostimulants against columnaris infections in rainbow trout (Oncorhynchus mykiss Walbaum) fingerlings was evaluated. Finnish F. columnare strains constituted a genetically homogeneous group that differed from strains isolated from other parts of the world and tolerated narrower pH and salinity ranges than F. columnare type strain (NCIMB 2248T). Finnish strains could be divided into seven genetic groups, which can co-occur during the same outbreak at fish farms. Among the genetic groups, four colony types were formed. Formation of rhizoid colonies is suggested to be a prerequisite for virulence of F. columnare. Colony types may have a role in the infection process and persistence of F. columnare at fish farms. The bacterium was able to survive in fresh water and also as a saprophyte, and to use saprophytism as a transmission strategy. These properties, together with co-occurrence of different genetic groups, may promote the continuous nature of outbreaks at fish farms and lead to development of highly virulent F. columnare strains. Immunostimulation was effective in boosting innate immune defence parameters of rainbow trout, but was inefficient in protecting fish against F. columnare infections. This suggests that antibody-mediated immunity is also essential in protecting fish from columnaris disease.en
dc.format.extent69 sivua
dc.language.isoeng
dc.publisherUniversity of Jyväskylä
dc.relation.ispartofseriesJyväskylä studies in biological and environmental science
dc.relation.isversionofISBN 978-951-39-3853-6
dc.subject.otherkalapatogeenit
dc.subject.othersaprofytia
dc.subject.otherimmunostimulaatio
dc.subject.othervirulenssi
dc.subject.othercolumnaris disease
dc.subject.otherfish pathogens
dc.subject.othersaprophytism
dc.subject.otherimmunostimulation
dc.subject.othervirulence
dc.subject.otherbacterial colony types
dc.titleCharacterizing the bacterial fish pathogen Flavobacterium columnare, and some factors affecting its pathogenicity
dc.typeDiss.
dc.identifier.urnURN:ISBN:978-951-39-3867-3
dc.type.dcmitypeTexten
dc.type.ontasotVäitöskirjafi
dc.type.ontasotDoctoral dissertationen
dc.contributor.tiedekuntaMatemaattis-luonnontieteellinen tiedekuntafi
dc.contributor.tiedekuntaFaculty of Mathematics and Scienceen
dc.contributor.yliopistoUniversity of Jyväskyläen
dc.contributor.yliopistoJyväskylän yliopistofi
dc.contributor.oppiaineBiologiafi
dc.relation.issn1456-9701
dc.relation.numberinseries206
dc.rights.accesslevelopenAccessfi
dc.subject.ysotaudinaiheuttajat


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