Bovine herpesvirus-1: evaluation of genetic diversity of subtypes derived from field strains of varied clinical syndromes and their relationship to vaccine strains

Vaccine. 2015 Jan 15;33(4):549-58. doi: 10.1016/j.vaccine.2014.11.033. Epub 2014 Nov 30.

Abstract

Bovine herpesvirus-1 (BoHV-1) causes significant disease in cattle. Control programs in North America incorporate vaccination with modified live viral (MLV) or killed (KV) vaccine. BoHV-1 strains are isolated from diseased animals or fetuses after vaccination. There are markers for differentiating MLV from field strains using whole-genome sequencing and analysis identifying single nucleotide polymorphisms (SNPs). Using multiple primer sets and sequencing of products permits association of BoHV-1 isolates with vaccines. To determine association between vaccine virus and strains isolated from clinical cases following vaccination, we analyzed 12 BoHV-1 isolates from animals with various clinical syndromes; 9 corresponded to BoHV-1.1 respiratory group. The remaining three corresponded to BoHV-1.2b, typically found in genital tracts of cattle. Four BoHV-1 isolates were identical to a vaccine strain; three were from post-vaccination abortion episodes with typical herpetic lesions whose dams had received MLV vaccine during pregnancy, and one from a heifer given a related MLV vaccine; Sequences of two respiratory isolates perfectly matched mutations characterizing RLB106 strain, a temperature sensitive mutant used in intranasal and parenteral vaccines. The last three respiratory strains clearly appeared related to a group of MLV vaccines. Previously the MLV vaccines were grouped into four groups based on SNPs patterns. In contrast with above-mentioned isolates that closely matched SNP patterns of their respective MLV vaccine virus, these 3 strains both lacked some and possessed a number of additional mutations compared to a group of MLV vaccine viral genome. Finding BoHV-1.2b in respiratory cases indicates focus should be given BoHV-1.2b as an emerging virus or a virus not recognized nor fully characterized in BRD.

Keywords: Bovine herpesvirus-1; Clinical syndromes; Genetics; Vaccines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Cattle Diseases / prevention & control*
  • Cattle Diseases / virology*
  • DNA, Viral / chemistry
  • DNA, Viral / genetics
  • Female
  • Genetic Variation*
  • Genotype
  • Herpesviridae Infections / pathology
  • Herpesviridae Infections / veterinary*
  • Herpesviridae Infections / virology*
  • Herpesvirus 1, Bovine / classification*
  • Herpesvirus 1, Bovine / genetics*
  • Herpesvirus 1, Bovine / isolation & purification
  • Herpesvirus Vaccines / immunology*
  • Mutation
  • North America
  • Polymorphism, Single Nucleotide
  • Pregnancy
  • Sequence Analysis, DNA

Substances

  • DNA, Viral
  • Herpesvirus Vaccines