Emergence of a virulent porcine reproductive and respiratory syndrome virus in vaccinated herds in the United States

Virus Res. 2015 Dec 2:210:34-41. doi: 10.1016/j.virusres.2015.07.004. Epub 2015 Jul 11.

Abstract

In early 2014, a Minnesota sow farm with a solid vaccination history suffered a severe porcine reproductive and respiratory syndrome (PRRS) outbreak with unusually high morbidity and mortality in piglets and sows, as well as anorexia and secondary bacterial infections in nursery pigs. Due to the unusual clinical severity in a PRRS-immune herd, genetic characteristics of the virus were examined to determine if a new PRRSV genotype had emerged. Phylogenetic analysis indicated that the virulent strain (PRRSV2/USA/Minnesota414/2014) was related to virulent strains circulating in the mid-western United States in recent years, and that the nonstructural protein 2 (nsp2) gene of MN414 contained an insertion-deletion pattern typical of existing type 2 virulent strains. We conclude that the MN414 isolate is a recently evolved member of the virulent lineage 1 family of type 2 PRRSV.

Keywords: Full genome; Phylogeny; Type 2 PRRSV; Virulent strain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cluster Analysis
  • Disease Outbreaks
  • Evolution, Molecular
  • Genome, Viral*
  • Minnesota / epidemiology
  • Molecular Sequence Data
  • Phylogeny
  • Porcine Reproductive and Respiratory Syndrome / epidemiology*
  • Porcine Reproductive and Respiratory Syndrome / virology*
  • Porcine respiratory and reproductive syndrome virus / classification*
  • Porcine respiratory and reproductive syndrome virus / isolation & purification*
  • Porcine respiratory and reproductive syndrome virus / pathogenicity
  • RNA, Viral / genetics*
  • Sequence Analysis, DNA*
  • Sequence Homology
  • Swine
  • Virulence

Substances

  • RNA, Viral

Associated data

  • GENBANK/KT581982