Virulence marker candidates in N-protein of viral haemorrhagic septicaemia virus (VHSV): virulence variability within VHSV Ib clones

Takafumi Ito*, Jun Kurita, Koh-ichiro Mori, Helle Frank Skall, Niels Lorenzen, Niccolò Vendramin, Nikolaj Gedsted Andersen, Katja Einer-Jensen, Niels Jørgen Olesen

*Corresponding author for this work

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    Abstract

    Four major genotypes of viral haemorrhagic septicaemia virus (VHSV), which have been isolated from many marine and freshwater fish species, are known to differ in virulence. While fast and low-cost genotyping systems based on monoclonal antibodies (MAbs) have been developed for typing of VHSV virulence, there is a need for supplementing the knowledge. In particular, 2 field isolates from viral haemorrhagic septicaemia (VHS) outbreaks in sea-reared rainbow trout Oncorhynchus mykiss in Sweden, SE-SVA-14 and SE-SVA-1033 (both genotype Ib), have yielded contradictory reactions. In the present study, upon cloning by limited dilution, both isolates appeared to be heterogeneous in terms of reactivity with nucleo (N)-protein-specific MAbs as well their gene sequences. Infection trials in rainbow trout further revealed differences in the virulence of these virus clones derived from the same primary isolate. Based on a comparative analysis of the entire genome of the clones tested, we suggest that the differences in virulence are tentatively linked to substitutions of amino acids (aa) in the N-protein region covered by aa 43-46 and aa position 168, or a combination of the two. The fact that such minor naturally occurring genetic differences affect the virulence implies that even low-virulent VHSV isolates in the marine environment should be considered as a potential threat for the trout farming industry. The described MAbs can represent useful tools for initial risk assessment of disease outbreaks in farmed trout by marine VHSV isolates.
    Original languageEnglish
    JournalDiseases of Aquatic Organisms
    Volume128
    Issue number1
    Pages (from-to)51-62
    Number of pages12
    ISSN0177-5103
    DOIs
    Publication statusPublished - 2018

    Keywords

    • Viral haemorrhagic septicaemia virus
    • VHSV
    • Virulence
    • Oncorhynchus mykiss
    • Genotype Ib
    • Nucleo-protein

    Cite this

    Ito, Takafumi ; Kurita, Jun ; Mori, Koh-ichiro ; Skall, Helle Frank ; Lorenzen, Niels ; Vendramin, Niccolò ; Andersen, Nikolaj Gedsted ; Einer-Jensen, Katja ; Olesen, Niels Jørgen. / Virulence marker candidates in N-protein of viral haemorrhagic septicaemia virus (VHSV): virulence variability within VHSV Ib clones. In: Diseases of Aquatic Organisms. 2018 ; Vol. 128, No. 1. pp. 51-62.
    @article{0a536ebd79364f7ab008c0078e3e6a1e,
    title = "Virulence marker candidates in N-protein of viral haemorrhagic septicaemia virus (VHSV): virulence variability within VHSV Ib clones",
    abstract = "Four major genotypes of viral haemorrhagic septicaemia virus (VHSV), which have been isolated from many marine and freshwater fish species, are known to differ in virulence. While fast and low-cost genotyping systems based on monoclonal antibodies (MAbs) have been developed for typing of VHSV virulence, there is a need for supplementing the knowledge. In particular, 2 field isolates from viral haemorrhagic septicaemia (VHS) outbreaks in sea-reared rainbow trout Oncorhynchus mykiss in Sweden, SE-SVA-14 and SE-SVA-1033 (both genotype Ib), have yielded contradictory reactions. In the present study, upon cloning by limited dilution, both isolates appeared to be heterogeneous in terms of reactivity with nucleo (N)-protein-specific MAbs as well their gene sequences. Infection trials in rainbow trout further revealed differences in the virulence of these virus clones derived from the same primary isolate. Based on a comparative analysis of the entire genome of the clones tested, we suggest that the differences in virulence are tentatively linked to substitutions of amino acids (aa) in the N-protein region covered by aa 43-46 and aa position 168, or a combination of the two. The fact that such minor naturally occurring genetic differences affect the virulence implies that even low-virulent VHSV isolates in the marine environment should be considered as a potential threat for the trout farming industry. The described MAbs can represent useful tools for initial risk assessment of disease outbreaks in farmed trout by marine VHSV isolates.",
    keywords = "Viral haemorrhagic septicaemia virus, VHSV, Virulence, Oncorhynchus mykiss, Genotype Ib, Nucleo-protein",
    author = "Takafumi Ito and Jun Kurita and Koh-ichiro Mori and Skall, {Helle Frank} and Niels Lorenzen and Niccol{\`o} Vendramin and Andersen, {Nikolaj Gedsted} and Katja Einer-Jensen and Olesen, {Niels J{\o}rgen}",
    year = "2018",
    doi = "10.3354/dao03215",
    language = "English",
    volume = "128",
    pages = "51--62",
    journal = "Diseases of Aquatic Organisms",
    issn = "0177-5103",
    publisher = "Inter Research",
    number = "1",

    }

    Virulence marker candidates in N-protein of viral haemorrhagic septicaemia virus (VHSV): virulence variability within VHSV Ib clones. / Ito, Takafumi; Kurita, Jun; Mori, Koh-ichiro; Skall, Helle Frank; Lorenzen, Niels; Vendramin, Niccolò; Andersen, Nikolaj Gedsted; Einer-Jensen, Katja; Olesen, Niels Jørgen.

    In: Diseases of Aquatic Organisms, Vol. 128, No. 1, 2018, p. 51-62.

    Research output: Contribution to journalJournal articleResearchpeer-review

    TY - JOUR

    T1 - Virulence marker candidates in N-protein of viral haemorrhagic septicaemia virus (VHSV): virulence variability within VHSV Ib clones

    AU - Ito, Takafumi

    AU - Kurita, Jun

    AU - Mori, Koh-ichiro

    AU - Skall, Helle Frank

    AU - Lorenzen, Niels

    AU - Vendramin, Niccolò

    AU - Andersen, Nikolaj Gedsted

    AU - Einer-Jensen, Katja

    AU - Olesen, Niels Jørgen

    PY - 2018

    Y1 - 2018

    N2 - Four major genotypes of viral haemorrhagic septicaemia virus (VHSV), which have been isolated from many marine and freshwater fish species, are known to differ in virulence. While fast and low-cost genotyping systems based on monoclonal antibodies (MAbs) have been developed for typing of VHSV virulence, there is a need for supplementing the knowledge. In particular, 2 field isolates from viral haemorrhagic septicaemia (VHS) outbreaks in sea-reared rainbow trout Oncorhynchus mykiss in Sweden, SE-SVA-14 and SE-SVA-1033 (both genotype Ib), have yielded contradictory reactions. In the present study, upon cloning by limited dilution, both isolates appeared to be heterogeneous in terms of reactivity with nucleo (N)-protein-specific MAbs as well their gene sequences. Infection trials in rainbow trout further revealed differences in the virulence of these virus clones derived from the same primary isolate. Based on a comparative analysis of the entire genome of the clones tested, we suggest that the differences in virulence are tentatively linked to substitutions of amino acids (aa) in the N-protein region covered by aa 43-46 and aa position 168, or a combination of the two. The fact that such minor naturally occurring genetic differences affect the virulence implies that even low-virulent VHSV isolates in the marine environment should be considered as a potential threat for the trout farming industry. The described MAbs can represent useful tools for initial risk assessment of disease outbreaks in farmed trout by marine VHSV isolates.

    AB - Four major genotypes of viral haemorrhagic septicaemia virus (VHSV), which have been isolated from many marine and freshwater fish species, are known to differ in virulence. While fast and low-cost genotyping systems based on monoclonal antibodies (MAbs) have been developed for typing of VHSV virulence, there is a need for supplementing the knowledge. In particular, 2 field isolates from viral haemorrhagic septicaemia (VHS) outbreaks in sea-reared rainbow trout Oncorhynchus mykiss in Sweden, SE-SVA-14 and SE-SVA-1033 (both genotype Ib), have yielded contradictory reactions. In the present study, upon cloning by limited dilution, both isolates appeared to be heterogeneous in terms of reactivity with nucleo (N)-protein-specific MAbs as well their gene sequences. Infection trials in rainbow trout further revealed differences in the virulence of these virus clones derived from the same primary isolate. Based on a comparative analysis of the entire genome of the clones tested, we suggest that the differences in virulence are tentatively linked to substitutions of amino acids (aa) in the N-protein region covered by aa 43-46 and aa position 168, or a combination of the two. The fact that such minor naturally occurring genetic differences affect the virulence implies that even low-virulent VHSV isolates in the marine environment should be considered as a potential threat for the trout farming industry. The described MAbs can represent useful tools for initial risk assessment of disease outbreaks in farmed trout by marine VHSV isolates.

    KW - Viral haemorrhagic septicaemia virus

    KW - VHSV

    KW - Virulence

    KW - Oncorhynchus mykiss

    KW - Genotype Ib

    KW - Nucleo-protein

    U2 - 10.3354/dao03215

    DO - 10.3354/dao03215

    M3 - Journal article

    C2 - 29565253

    VL - 128

    SP - 51

    EP - 62

    JO - Diseases of Aquatic Organisms

    JF - Diseases of Aquatic Organisms

    SN - 0177-5103

    IS - 1

    ER -