Abstract
Bovine rhinitis B virus (BRBV) (genus: Aphthovirus, family: Picornaviridae), is a significant etiological agent of the bovine respiratory disease complex. Despite global reports on BRBV, genomic data for Japanese strains are unregistered. Herein, we aimed to analyze the genetic characteristics of BRBV in Japan. In nasal swabs from 66 cattle, BRBV was detected in 7/10 and 4/56 symptomatic and asymptomatic cattle, respectively. Metagenomic sequencing and Sanger sequencing identified two Japanese BRBV strains, IBA/2211/2 and LAV/238002, which shared significant genetic similarity with known BRBV strains and exhibited unique mutations and recombination events, indicating dynamic evolution, influenced by regional environmental and biological factors. Notably, the leader gene of LAV/238002 was positioned in a distinct evolutionary lineage, significantly diverging from the other BRBV strains. Phylogenetic analysis based on the amino acid sequence of leader protein showed that both Japanese strains were in a distinctly different clade from other BRBV strains, indicating significant genetic diversity. These findings provide insights into the genetic makeup of the Japanese BRBV strains, enriching our understanding of their genetic diversity and evolutionary mechanisms.