The First Full-Genome Characterization and Phylogenetic Analysis of a Potential Recombinant Bovine Herpesvirus Type 1 Isolated in China

Abstract

Bovine herpesvirus type 1 (BHV-1) is a virus of causing bovine respiratory disease that poses significant threat to the cattle industry. The prevalence of BHV-1 has recently increased in China. However, information about the prevalent isolates is scarce. In this study, we identified a novel strain of BHV-1, referred to as BHV SHJS, isolated from nasal swabs of Holstein cows in 2020 of China. The genome of BHV SHJS is 1,35,102 bp in length and is 99.64 % similar to that of SP1777 (KM258883.1) strain. Mutations, insertions, or deletions mainly occur in UL12, UL19, UL27, UL37, UL42, UL44, UL46, UL47, US6, US7, and US8 relative to the different genomic coordinates. Phylogenetic analyses of immunogenic proteins (gB, gC, and gD) revealed that BHV SHJS and other China outbreak strains were displayed on different branches with commonly used vaccine strains. Recombination analysis shown that BHV SHJS could persist even with BoviShield IBR MLV and Arsenal IBR MLV vaccines, suggesting that these vaccines should not completely prevent BHV SHJS infection. These analyses partially explain why the vaccines only partially protect against BHV-1 outbreaks in China. In conclusion, we identified a novel and potential recombinant BHV-1 strain and for the first time characterized BHV-1 genome with a different evolutionary origin from that of known strains prevalent in China. This study will enrich our knowledge regarding BHV outbreak strains in China and contribute to the prevention and pathogenic studies of BHV-1.