title: Screening for viral hemorrhagic septicemia virus in marine fish along the Norwegian coastal line.
abstract: Viral hemorrhagic septicemia virus (VHSV) infects a wide range of marine fish species. To study the occurrence of VHSV in wild marine fish populations in Norwegian coastal waters and fjord systems a total of 1927 fish from 39 different species were sampled through 5 research cruises conducted in 2009 to 2011. In total, VHSV was detected by rRT-PCR in twelve samples originating from Atlantic herring (Clupea harengus), haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus) and silvery pout (Gadiculus argenteus). All fish tested positive in gills while four herring and one silvery pout also tested positive in internal organs. Successful virus isolation in cell culture was only obtained from one pooled Atlantic herring sample which shows that today's PCR methodology have a much higher sensitivity than cell culture for detection of VHSV. Sequencing revealed that the positive samples belonged to VHSV genotype Ib and phylogenetic analysis shows that the isolate from Atlantic herring and silvery pout are closely related. All positive fish were sampled in the same area in the northern county of Finnmark. This is the first detection of VHSV in Atlantic herring this far north, and to our knowledge the first detection of VHSV in silvery pout. However, low prevalence of VHSV genotype Ib in Atlantic herring and other wild marine fish are well known in other parts of Europe. Earlier there have been a few reports of disease outbreaks in farmed rainbow trout with VHSV of genotype Ib, and our results show that there is a possibility of transfer of VHSV from wild to farmed fish along the Norwegian coast line. The impact of VHSV on wild fish is not well documented.
authors.affiliation: Research group Disease and Pathogen transmission, Institute of Marine Research, Bergen, Norway.
authors.forename: Nina
authors.initials: N
authors.lastname: Sandlund
authors.affiliation: Section of Virology, National Veterinary Institute, Oslo, Norway.
authors.forename: Britt
authors.initials: B
authors.lastname: Gjerset
authors.affiliation: Research group Oceanography and climate, Institute of Marine Research, Bergen, Norway.
authors.forename: Øivind
authors.initials: Ø
authors.lastname: Bergh
authors.affiliation: Section of Virology, National Veterinary Institute, Oslo, Norway.
authors.forename: Ingebjørg
authors.initials: I
authors.lastname: Modahl
authors.affiliation: Section of Virology, Technical University of Denmark, Frederiksberg C, Denmark.
authors.forename: Niels Jørgen
authors.initials: NJ
authors.lastname: Olesen
authors.affiliation: Section of Virology, National Veterinary Institute, Oslo, Norway.
authors.forename: Renate
authors.initials: R
authors.lastname: Johansen
mesh_terms: D000367:Age Factors; D000818:Animals; D058070:Asymptomatic Diseases; D001267:Atlantic Ocean; D001483:Base Sequence; D004197:Disease Reservoirs; D004198:Disease Susceptibility; D005399:Fishes / Q000821:virology*; D005880:Gills / Q000821:virology; D031941:Hemorrhagic Septicemia, Viral / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D008969:Molecular Sequence Data; D009664:Norway; D029141:Novirhabdovirus / Q000302:isolation & purification*; D010802:Phylogeny; D015995:Prevalence; D012367:RNA, Viral / Q000302:isolation & purification; D017423:Sequence Analysis, RNA; D013045:Species Specificity; D014781:Viscera / Q000821:virology
chemical_list: D012367:RNA, Viral