Natural recombination of equine hepacivirus subtype 1 within the NS5A and NS5B genes.

Equine hepacivirus (EqHV) was first reported in 2012 and is the closest known homolog of hepatitis C virus (HCV). A number of studies have reported HCV recombination events. The aim of this study was to determine whether recombination events occur in EqHV strains. Considering that no information on the Chinese EqHV genome sequence is available, we first sequenced the near-complete genomes of three field EqHV strains. Through systemic analysis, we obtained strong evidence supporting a recombination event within the NS5A and NS5B genes in the American EqHV strains, but not in the strains from China or other countries. Finally, using cut-off values for determination of HCV genotypes and subtypes, we classified the EqHV strains from around the world into one unique genotype and three subtypes. The recombination event occurred in subtype 1 EqHV strains. This study provides critical insights into the genetic variability and evolution of EqHV.