Genetic and biological characterization of a Porcine Reproductive and Respiratory Syndrome Virus 2 (PRRSV-2)causing significant clinical disease in the field

Lise Kirstine Kvisgaard, Lars Erik Larsen, Charlotte Kristiane Hjulsager, Anette Bøtner, P. H. Rathkjen, Peter Mikael Helweg Heegaard, N. P. Bisgaard, J. Nielsen, Mette Sif Hansen

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    Abstract

    Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is the cause of severe reproductive and respiratory disease in swine worldwide. In Denmark, both PRRSV-1 and PRRSV-2 are circulating and approximately 35% of pig herds are seropositive for PRRSV. In November 2010, a pig herd in the Northern part of Denmark experienced an infection with PRRSV-2 with clinical signs that were much more severe than normally reported from current Danish PRRSV-2 affected herds. Due to the clinical observations of reproductive failure in sows and high mortality in piglets, it was speculated that a new, more pathogenic or vaccine evading PRRSV strain had emerged in Denmark. The overall aim of the present study was to perform a genetic and biological characterization of the virus isolated from the diseased herd. Complete genome sequencing of isolates from this herd revealed that although the case strain had some unique genetic features including a deduced 3 amino acid deletion, it was in overall very similar to the other PRRS-2 viruses circulating in Denmark. In an experimental trial in growing pigs, no overt clinical signs or pathology were observed following intranasal inoculation with the new virus isolate. Virus shedding, acute phase protein responses and serological responses were comparable to those seen after experimental challenge with a Danish PRRSV-2 reference strain isolated in 1997. Vaccination with a commercial modified live PRRSV-2 vaccine had a clear reducing effect on virus shedding, magnitude, and duration of viremia and viral load in the lungs. Overall, the results indicate that the severe disease observed in the field was contributed by additional factors in combination with the PRRS virus infection.
    Original languageEnglish
    JournalVeterinary Microbiology
    Volume211
    Pages (from-to)74-83
    ISSN0378-1135
    DOIs
    Publication statusPublished - 2017

    Bibliographical note

    This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).

    Keywords

    • PRRSV
    • PRRSV-2
    • Type 2
    • Virulence
    • Pigs
    • Experimental infection

    Cite this

    Kvisgaard, Lise Kirstine ; Larsen, Lars Erik ; Hjulsager, Charlotte Kristiane ; Bøtner, Anette ; Rathkjen, P. H. ; Heegaard, Peter Mikael Helweg ; Bisgaard, N. P. ; Nielsen, J. ; Hansen, Mette Sif. / Genetic and biological characterization of a Porcine Reproductive and Respiratory Syndrome Virus 2 (PRRSV-2)causing significant clinical disease in the field. In: Veterinary Microbiology. 2017 ; Vol. 211. pp. 74-83.
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    abstract = "Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is the cause of severe reproductive and respiratory disease in swine worldwide. In Denmark, both PRRSV-1 and PRRSV-2 are circulating and approximately 35{\%} of pig herds are seropositive for PRRSV. In November 2010, a pig herd in the Northern part of Denmark experienced an infection with PRRSV-2 with clinical signs that were much more severe than normally reported from current Danish PRRSV-2 affected herds. Due to the clinical observations of reproductive failure in sows and high mortality in piglets, it was speculated that a new, more pathogenic or vaccine evading PRRSV strain had emerged in Denmark. The overall aim of the present study was to perform a genetic and biological characterization of the virus isolated from the diseased herd. Complete genome sequencing of isolates from this herd revealed that although the case strain had some unique genetic features including a deduced 3 amino acid deletion, it was in overall very similar to the other PRRS-2 viruses circulating in Denmark. In an experimental trial in growing pigs, no overt clinical signs or pathology were observed following intranasal inoculation with the new virus isolate. Virus shedding, acute phase protein responses and serological responses were comparable to those seen after experimental challenge with a Danish PRRSV-2 reference strain isolated in 1997. Vaccination with a commercial modified live PRRSV-2 vaccine had a clear reducing effect on virus shedding, magnitude, and duration of viremia and viral load in the lungs. Overall, the results indicate that the severe disease observed in the field was contributed by additional factors in combination with the PRRS virus infection.",
    keywords = "PRRSV, PRRSV-2, Type 2, Virulence, Pigs, Experimental infection",
    author = "Kvisgaard, {Lise Kirstine} and Larsen, {Lars Erik} and Hjulsager, {Charlotte Kristiane} and Anette B{\o}tner and Rathkjen, {P. H.} and Heegaard, {Peter Mikael Helweg} and Bisgaard, {N. P.} and J. Nielsen and Hansen, {Mette Sif}",
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    Genetic and biological characterization of a Porcine Reproductive and Respiratory Syndrome Virus 2 (PRRSV-2)causing significant clinical disease in the field. / Kvisgaard, Lise Kirstine; Larsen, Lars Erik; Hjulsager, Charlotte Kristiane; Bøtner, Anette; Rathkjen, P. H.; Heegaard, Peter Mikael Helweg; Bisgaard, N. P.; Nielsen, J.; Hansen, Mette Sif.

    In: Veterinary Microbiology, Vol. 211, 2017, p. 74-83.

    Research output: Contribution to journalJournal articleResearchpeer-review

    TY - JOUR

    T1 - Genetic and biological characterization of a Porcine Reproductive and Respiratory Syndrome Virus 2 (PRRSV-2)causing significant clinical disease in the field

    AU - Kvisgaard, Lise Kirstine

    AU - Larsen, Lars Erik

    AU - Hjulsager, Charlotte Kristiane

    AU - Bøtner, Anette

    AU - Rathkjen, P. H.

    AU - Heegaard, Peter Mikael Helweg

    AU - Bisgaard, N. P.

    AU - Nielsen, J.

    AU - Hansen, Mette Sif

    N1 - This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).

    PY - 2017

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    N2 - Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is the cause of severe reproductive and respiratory disease in swine worldwide. In Denmark, both PRRSV-1 and PRRSV-2 are circulating and approximately 35% of pig herds are seropositive for PRRSV. In November 2010, a pig herd in the Northern part of Denmark experienced an infection with PRRSV-2 with clinical signs that were much more severe than normally reported from current Danish PRRSV-2 affected herds. Due to the clinical observations of reproductive failure in sows and high mortality in piglets, it was speculated that a new, more pathogenic or vaccine evading PRRSV strain had emerged in Denmark. The overall aim of the present study was to perform a genetic and biological characterization of the virus isolated from the diseased herd. Complete genome sequencing of isolates from this herd revealed that although the case strain had some unique genetic features including a deduced 3 amino acid deletion, it was in overall very similar to the other PRRS-2 viruses circulating in Denmark. In an experimental trial in growing pigs, no overt clinical signs or pathology were observed following intranasal inoculation with the new virus isolate. Virus shedding, acute phase protein responses and serological responses were comparable to those seen after experimental challenge with a Danish PRRSV-2 reference strain isolated in 1997. Vaccination with a commercial modified live PRRSV-2 vaccine had a clear reducing effect on virus shedding, magnitude, and duration of viremia and viral load in the lungs. Overall, the results indicate that the severe disease observed in the field was contributed by additional factors in combination with the PRRS virus infection.

    AB - Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is the cause of severe reproductive and respiratory disease in swine worldwide. In Denmark, both PRRSV-1 and PRRSV-2 are circulating and approximately 35% of pig herds are seropositive for PRRSV. In November 2010, a pig herd in the Northern part of Denmark experienced an infection with PRRSV-2 with clinical signs that were much more severe than normally reported from current Danish PRRSV-2 affected herds. Due to the clinical observations of reproductive failure in sows and high mortality in piglets, it was speculated that a new, more pathogenic or vaccine evading PRRSV strain had emerged in Denmark. The overall aim of the present study was to perform a genetic and biological characterization of the virus isolated from the diseased herd. Complete genome sequencing of isolates from this herd revealed that although the case strain had some unique genetic features including a deduced 3 amino acid deletion, it was in overall very similar to the other PRRS-2 viruses circulating in Denmark. In an experimental trial in growing pigs, no overt clinical signs or pathology were observed following intranasal inoculation with the new virus isolate. Virus shedding, acute phase protein responses and serological responses were comparable to those seen after experimental challenge with a Danish PRRSV-2 reference strain isolated in 1997. Vaccination with a commercial modified live PRRSV-2 vaccine had a clear reducing effect on virus shedding, magnitude, and duration of viremia and viral load in the lungs. Overall, the results indicate that the severe disease observed in the field was contributed by additional factors in combination with the PRRS virus infection.

    KW - PRRSV

    KW - PRRSV-2

    KW - Type 2

    KW - Virulence

    KW - Pigs

    KW - Experimental infection

    U2 - 10.1016/j.vetmic.2017.10.001

    DO - 10.1016/j.vetmic.2017.10.001

    M3 - Journal article

    VL - 211

    SP - 74

    EP - 83

    JO - Veterinary Microbiology

    JF - Veterinary Microbiology

    SN - 0378-1135

    ER -