Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Apr 19;14(1):133.
doi: 10.1186/s12917-018-1451-y.

Efficacy of live attenuated porcine reproductive and respiratory syndrome virus 2 strains to protect pigs from challenge with a heterologous Vietnamese PRRSV 2 field strain

Tatjana Sattler  1   2 , Jutta Pikalo  3 , Eveline Wodak  3 , Sandra Revilla-Fernández  3 , Adi Steinrigl  3 , Zoltán Bagó  3 , Ferdinand Entenfellner  4 , Jean-Baptiste Claude  5 , Floriane Pez  5 , Maela Francillette  5 , Friedrich Schmoll  3
Affiliations

Efficacy of live attenuated porcine reproductive and respiratory syndrome virus 2 strains to protect pigs from challenge with a heterologous Vietnamese PRRSV 2 field strain

Tatjana Sattler et al. BMC Vet Res. .

Abstract

Background: Effective vaccines against porcine reproductive and respiratory syndrome virus (PRRSV), especially against highly pathogenic (HP) PRRSV are still missing. The objective of this study was to evaluate the protective efficacy of an experimental live attenuated PRRSV 2 vaccine, composed of two strains, against heterologous challenge with a Vietnamese HP PRRSV 2 field strain. For this reason, 20 PRRSV negative piglets were divided into two groups. The pigs of group 1 were vaccinated with the experimental vaccine, group 2 remained unvaccinated. All study piglets received an intranasal challenge of the HP PRRSV 2 on day 0 of the study (42 days after vaccination). Blood samples were taken on days 7 and 21 after vaccination and on several days after challenge. On day 28 after challenge, all piglets were euthanized and pathologically examined.

Results: On days 7 and 21 after vaccination, a PRRSV 2 viraemia was seen in all piglets of group 1 which remained detectable in seven piglets up to 42 days after vaccination. On day 3 after challenge, all piglets from both groups were positive in PRRSV 2 RT-qPCR. From day 7 onwards, viral load and number of PRRSV 2 positive pigs were lower in group 1 than in group 2. All pigs of group 1 seroconverted after PRRSV 2 vaccination. PRRSV antibodies were detected in serum of all study pigs from both groups from day 14 after challenge onwards. In group 2, moderate respiratory symptoms with occasional coughing were seen following the challenge with HP PRRSV 2. Pigs of group 1 remained clinically unaffected. Interstitial pneumonia was found in four piglets of group 1 and in all ten piglets of group 2. Histopathological findings were more severe in group 2.

Conclusions: It was thus concluded that the used PRRSV 2 live experimental vaccine provided protection from clinical disease and marked reduction of histopathological findings and viral load in pigs challenged with a Vietnamese HP PRRSV 2 field strain.

Keywords: Efficacy; HP PRRSV 2; Immune response; Vaccine; Viral replication.

PubMed Disclaimer

Conflict of interest statement

Ethics approval and consent to participate

Housing, animal care and experimental protocol (notification number LF1-TVG-26/022–2014) were approved by the local ethics committee (Agency of the Government in Lower Austria, Department of Agrarian Law). The study piglets were bought by the Austrian Agency for Health and Food Safety for conduction of the study. Consent was given from the original owner of the pigs to conduct the study and take samples.

Competing interests

The authors declare that they have no competing interest.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
PRRSV loads (copies/ml) in serum (a) and tissue samples (b) of the study piglets. Blood sampling points were: before vaccination (day − 42), days − 35, − 21, 0, 3, 7, 10, 14, 21 and 28 after challenge with an HP PRRSV 2 field strain; tissue sample were collected on day 28. Data are given as median, 1st and 3rd quartile. Group 1: pre-vaccinated with a new PRRSV 2 live vaccine, group 2: not pre-vaccinated. On time points marked with *, differences between the groups were significant
Fig. 2
Fig. 2
Neighbour joining tree based on partial ORF5 sequences. Obtained from samples of the study piglets, the challenge virus (AGES 760) and the tested experimental PRRSV 2 live vaccine (AGES 1048). Sequences from the two virus strains included in the experimental vaccine (Vaccine strain 1 and 2) were kindly provided by Kyoto Biken. The size of the alignment was 218 bp. Numbers along the branches show the percentage of 1000 bootstrap iterations
Fig. 3
Fig. 3
Multiple alignment (a), neighbour joining tree (b) and nucleotide sequence identity matrix (c). Graphical view for selected references, sequenced samples of the study piglets, the challenge virus and the tested PRRSV 2 live vaccine. Reference strains: Lelystad virus for PRRSV 1, INGELVAC pMLV and VR2332 for PRRSV 2. The size of the alignment was 1201 bp. Numbers along the branches in (b) show the bootstrap values (%) after 1000 bootstrap iterations
Fig. 4
Fig. 4
Pulmonary lesions in pigs challenged with an HP PRRSV 2 field strain. a: pig from group 1 (vaccinated) without inflammatory alterations (score 0); b: pig from group 2 (non-vaccinated) showing moderate multifocal lymphohistiocytic interstitial pneumonia with peribronchial and perivascular accentuation (score 2); c: pig from group 2 displaying moderate diffuse lymphohistiocytic interstitial pneumonia with peribronchial, perivascular and intralobular accentuation (score 3). Microphoto; H&E-staining; Bar = 200 μm
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Adams MJ, Lefkowitz EL, King AMQ, Harrach B, Harrison RL, Knowles AM, et al. Ratification vote on taxonomic proposals to the international committee on taxonomy of viruses (2016) Arch Virol. 2016;161:2921–2949. doi: 10.1007/s00705-016-2977-6. - DOI - PMC - PubMed
    1. Wensvoort G. Lelystad virus and the porcine epidemic abortion and respiratory syndrome. Vet Res. 1993;24:117–124. - PubMed
    1. Nelson EA, Christopher-Hennings J, Drew T, Wensvoort G, Collins JE, Benfield DA. Differentiation of U.S. and European isolates of porcine reproductive and respiratory syndrome virus by monoclonal antibodies. J Clin Microbiol. 1993;31:3184–3189. - PMC - PubMed
    1. Stadejek T, Stankevicius A, Murtaugh MP, Oleksiewicz MB. Molecular evolution of PRRSV in Europe: current state of play. Vet Microbiol. 2013;165:21–28. doi: 10.1016/j.vetmic.2013.02.029. - DOI - PubMed
    1. Tian K, Yu X, Zhao T, Feng Y, Cao Z, Wang C, et al. Emergence of fatal PRRSV variants: unparalleled outbreaks of atypical PRRS in China and molecular dissection of the unique hallmark. PLoS One. 2007;2:e526. doi: 10.1371/journal.pone.0000526. - DOI - PMC - PubMed

MeSH terms