First identification and genomic characterization of equine hepacivirus sub-type 3 strain in China.

Equine Hepacivirus (EqHV) is a newly discovered equine virus that is classified under the Hepacivirus genus of the Flaviviridae family. There are three sub-types of EqHV worldwide namely; sub-types 1-3. The majority of EqHV sub-type 1 strains were found in China. While different sub-types have been found in Japan and USA, therefore, to investigate whether the other sub-types of EqHV strains were present in China, a total of 60 horse serum samples were collected and screened for EqHV RNA through RT-PCR. The results revealed that 19 serum samples were RNA-positive (19/60) and the EqHV detection rate was 31.67%. One EqHV strain named GD23 was obtained and its near-complete genome sequence was acquired. Analysis of nucleotide p-distance with reference to the entire polyprotein gene revealed that GD23 was classified into sub-type 3. In addition, the phylogenetic analysis demonstrated that GD23 was clustered together with EqHV strains of sub-type 3 in other countries. The present study is the first to identify an EqHV sub-type 3 strain in China.