Characterization of a VHS virus genotype III isolated from rainbow trout (Oncorhychus mykiss) at a marine site on the west coast of Norway

Abstract Background Norwegian production of rainbow trout ( Oncorhynchus mykiss ) has been without any outbreaks of VHS for many years until the disease emerged in a farm in western Norway in November 2007. The fish were, in addition to VHS virus, positive for gill chlamydia-like bacteria, Flavobact...

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Main Authors: Duesund, Henrik, Nylund, Stian, Watanabe, Kuninori, Ottem, Karl F, Nylund, Are
Format: Other/Unknown Material
Language:English
Published: BioMed Central Ltd. 2010
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Online Access:http://www.virologyj.com/content/7/1/19
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spelling ftbiomed:oai:biomedcentral.com:1743-422X-7-19 2023-05-15T17:38:44+02:00 Characterization of a VHS virus genotype III isolated from rainbow trout (Oncorhychus mykiss) at a marine site on the west coast of Norway Duesund, Henrik Nylund, Stian Watanabe, Kuninori Ottem, Karl F Nylund, Are 2010-01-26 http://www.virologyj.com/content/7/1/19 en eng BioMed Central Ltd. http://www.virologyj.com/content/7/1/19 Copyright 2010 Duesund et al; licensee BioMed Central Ltd. Research 2010 ftbiomed 2010-02-21T00:26:34Z Abstract Background Norwegian production of rainbow trout ( Oncorhynchus mykiss ) has been without any outbreaks of VHS for many years until the disease emerged in a farm in western Norway in November 2007. The fish were, in addition to VHS virus, positive for gill chlamydia-like bacteria, Flavobacterium psychrophilum , and a microsporidian. A new VHS virus genotype III was isolated from the fish in RTgill-W1 cells and the complete coding region (11,065 nucleotides) was sequenced. This virus was also used in a challenge experiment to see if it could cause any mortality in rainbow trout in sea water. Results This is the first time a nearly complete sequence of a genotype III virus isolate has been presented. The organization of the genes is the same as in the other VHS virus genotypes studied (GI and GIV). Between the ORFs are nontranslated regions that contain highly conserved sequences encompassing the polyadenylation signal for one gene, and the putative transcription initiation site of the next gene. The intergenic regions vary in length from 74 nt to 128 nt. The nucleotide sequence is more similar to genotype I isolates compared to isolates from genotype II and IV. Analyses of the sequences of the N and G protein genes show that this new isolate is distinct from other VHS virus isolates and groups closely together with isolates from genotype III. In a challenge experiment, using intraperitoneal (ip) injection of the isolate, co-habitation with infected fish, and bath challenge, mortalities slightly above 40% were obtained. There was no significant difference in mortality between the bath challenged group and the ip injected group, while the mortality in the co-habitation group was as low as 30%. Conclusions All VHS virus isolates in genotype III are from marine fish in the North East Atlantic. Unlike the other known genotype III isolates, which are of low virulence, this new isolate is moderately virulent. It was not possible to detect any changes in the virus genome that could explain the higher virulence. A major problem for the study of virulence factors is the lack of information about other genotype III isolates. Other/Unknown Material North East Atlantic BioMed Central Norway
institution Open Polar
collection BioMed Central
op_collection_id ftbiomed
language English
description Abstract Background Norwegian production of rainbow trout ( Oncorhynchus mykiss ) has been without any outbreaks of VHS for many years until the disease emerged in a farm in western Norway in November 2007. The fish were, in addition to VHS virus, positive for gill chlamydia-like bacteria, Flavobacterium psychrophilum , and a microsporidian. A new VHS virus genotype III was isolated from the fish in RTgill-W1 cells and the complete coding region (11,065 nucleotides) was sequenced. This virus was also used in a challenge experiment to see if it could cause any mortality in rainbow trout in sea water. Results This is the first time a nearly complete sequence of a genotype III virus isolate has been presented. The organization of the genes is the same as in the other VHS virus genotypes studied (GI and GIV). Between the ORFs are nontranslated regions that contain highly conserved sequences encompassing the polyadenylation signal for one gene, and the putative transcription initiation site of the next gene. The intergenic regions vary in length from 74 nt to 128 nt. The nucleotide sequence is more similar to genotype I isolates compared to isolates from genotype II and IV. Analyses of the sequences of the N and G protein genes show that this new isolate is distinct from other VHS virus isolates and groups closely together with isolates from genotype III. In a challenge experiment, using intraperitoneal (ip) injection of the isolate, co-habitation with infected fish, and bath challenge, mortalities slightly above 40% were obtained. There was no significant difference in mortality between the bath challenged group and the ip injected group, while the mortality in the co-habitation group was as low as 30%. Conclusions All VHS virus isolates in genotype III are from marine fish in the North East Atlantic. Unlike the other known genotype III isolates, which are of low virulence, this new isolate is moderately virulent. It was not possible to detect any changes in the virus genome that could explain the higher virulence. A major problem for the study of virulence factors is the lack of information about other genotype III isolates.
format Other/Unknown Material
author Duesund, Henrik
Nylund, Stian
Watanabe, Kuninori
Ottem, Karl F
Nylund, Are
spellingShingle Duesund, Henrik
Nylund, Stian
Watanabe, Kuninori
Ottem, Karl F
Nylund, Are
Characterization of a VHS virus genotype III isolated from rainbow trout (Oncorhychus mykiss) at a marine site on the west coast of Norway
author_facet Duesund, Henrik
Nylund, Stian
Watanabe, Kuninori
Ottem, Karl F
Nylund, Are
author_sort Duesund, Henrik
title Characterization of a VHS virus genotype III isolated from rainbow trout (Oncorhychus mykiss) at a marine site on the west coast of Norway
title_short Characterization of a VHS virus genotype III isolated from rainbow trout (Oncorhychus mykiss) at a marine site on the west coast of Norway
title_full Characterization of a VHS virus genotype III isolated from rainbow trout (Oncorhychus mykiss) at a marine site on the west coast of Norway
title_fullStr Characterization of a VHS virus genotype III isolated from rainbow trout (Oncorhychus mykiss) at a marine site on the west coast of Norway
title_full_unstemmed Characterization of a VHS virus genotype III isolated from rainbow trout (Oncorhychus mykiss) at a marine site on the west coast of Norway
title_sort characterization of a vhs virus genotype iii isolated from rainbow trout (oncorhychus mykiss) at a marine site on the west coast of norway
publisher BioMed Central Ltd.
publishDate 2010
url http://www.virologyj.com/content/7/1/19
geographic Norway
geographic_facet Norway
genre North East Atlantic
genre_facet North East Atlantic
op_relation http://www.virologyj.com/content/7/1/19
op_rights Copyright 2010 Duesund et al; licensee BioMed Central Ltd.
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