Pseudorabies virus variant in Bartha-K61-vaccinated pigs, China, 2012

Emerg Infect Dis. 2013 Nov;19(11):1749-55. doi: 10.3201/eid1911.130177.

Abstract

The widely used pseudorabies virus (PRV) Bartha-K61 vaccine has played a key role in the eradication of PRV. Since late 2011, however, a disease characterized by neurologic symptoms and a high number of deaths among newborn piglets has occurred among Bartha-K61-vaccinated pigs on many farms in China. Clinical samples from pigs on 15 farms in 6 provinces were examined. The PRV gE gene was detectable by PCR in all samples, and sequence analysis of the gE gene showed that all isolates belonged to a relatively independent cluster and contained 2 amino acid insertions. A PRV (named HeN1) was isolated and caused transitional fever in pigs. In protection assays, Bartha-K61 vaccine provided 100% protection against lethal challenge with SC (a classical PRV) but only 50% protection against 4 challenges with strain HeN1. The findings suggest that Bartha-K61 vaccine does not provide effective protection against PRV HeN1 infection.

Keywords: Bartha-K61 vaccine strain; China; immune evasion; pigs; pseudorabies virus; virulent; virus variant; viruses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Viral / immunology
  • China
  • Herpesvirus 1, Suid / genetics*
  • Herpesvirus 1, Suid / immunology*
  • Herpesvirus 1, Suid / isolation & purification
  • Neutralization Tests
  • Phylogeny
  • Pseudorabies / immunology*
  • Pseudorabies / prevention & control*
  • Pseudorabies Vaccines / immunology*
  • Swine
  • Swine Diseases*
  • Vaccination
  • Viral Envelope Proteins / genetics

Substances

  • Antibodies, Viral
  • Pseudorabies Vaccines
  • Viral Envelope Proteins