Genetic diversity of imported PRRSV-2 strains, 2005-2020, Hungary

Szilvia Jakab; Eszter Kaszab; Szilvia Marton; Krisztián Bányai; Ádám Bálint; Imre Nemes; István Szabó

doi:10.3389/fvets.2022.986850

Genetic diversity of imported PRRSV-2 strains, 2005-2020, Hungary

Front Vet Sci. 2022 Oct 11:9:986850. doi: 10.3389/fvets.2022.986850. eCollection 2022.

Authors

Szilvia Jakab^{1

2}, Eszter Kaszab^{1

2}, Szilvia Marton^{1

2}, Krisztián Bányai^{1

2

3}, Ádám Bálint⁴, Imre Nemes⁵, István Szabó⁶

Affiliations

¹ Veterinary Medical Research Institute, Budapest, Hungary.
² National Laboratory for Infectious Animal Diseases, Antimicrobial Resistance, Veterinary Public Health and Food Chain Safety, Budapest, Hungary.
³ Department of Pharmacology and Toxicology, University of Veterinary Medical Research, Budapest, Hungary.
⁴ Veterinary Diagnostic Directorate, National Food Chain Safety Office, Budapest, Hungary.
⁵ Hungarian Association for Porcine Health Management, Budapest, Hungary.
⁶ National PRRS Eradication Committee, Budapest, Hungary.

Abstract

Porcine reproductive and respiratory syndrome virus 2 (PRRSV-2) remains sporadic in Europe. In this study, we investigated the molecular epidemiology of PRRSV-2 infections encompassing 15 years in Hungary. Partial (423 bp long) ORF5 sequences (n = 44) from 20 Hungarian pig herds were analyzed. The study strains fell into two genetic lineages, L1 and L5, being L5 strains more prevalent (88.6 vs. 11.4%). Pairwise sequence identities within Hungarian representative PRRSV-2 strains ranged between 84.7 to 100% (nucleotide, nt) and 85 to 100% (amino acid, aa). When compared with reference strains, identity values fell between 87 and 100% (L1, nt 87-91%, aa 87-93%, reference strain IAF-exp91; L5, nt 87-100%, aa 88-100%, reference strain Ingelvac MLV). Epidemiologic examination implied that the majority of L5 strains were imported repeatedly from other European countries where Ingelvac MLV was approved for routine use. The emergence of L1 strains was thought to be associated with a single introduction and subsequent dissemination between pig farms of a large integrator. Results presented here contribute to a better understanding of the epizootiology of PRRSV-2 infections and shed light on the genetic diversity of viral strains in non-endemic countries.

Keywords: Betaarterivirus suid 2; ORF5; molecular epidemiology; phylogenetic analysis; vaccine virus.