Identification and genetic characterization of equine Pegivirus in China.

In 2013, two new viruses, equine pegivirus (EPgV) and Theiler's disease-associated virus (TDAV), both belonging to the genus Pegivirus within the family Flaviviridae, were identified. To investigate the geographical distribution and genetic diversity of these two viruses in China, we screened EPgV and TDAV infection in imported race horses and Chinese work horses by using reverse-transcription polymerase chain reaction (RT-PCR). EPgV was detected in 10.8 % (8/74) of the total horses tested, with a prevalence of 5.8 and 22.7 % in the race horses and work horses, respectively. No TDAV infection was found. A near full-length genome sequence of EPgV was obtained that showed an identity of 89.5-90.6 % at the nucleotide level and 98.1-98.3 % at the amino acid level with an American strain, C0035, and another Chinese strain, LW/216, respectively. Phylogenetic analysis showed two different clusters of the sequences from the race horses and work horses, indicating a difference in virus origin. Our results demonstrated a higher positive rate of EPgV in the Chinese work horses than in the imported race horses, a moderate genetic diversity of EPgV strains worldwide and possibly no liver pathogenesis for EPgV infection.

PCR-based screening and phylogenetic analysis of rat pegivirus (RPgV) carried by rodents in China.

Rodent-borne pegiviruses were initially identified in serum samples from desert wood-rats in 2013, and subsequently in serum samples from commensal rats in 2014. However, the prevalence and phylogenetic characteristics of rodent pegiviruses in China are poorly understood. In this study, we screened serum samples collected from wild rats in southern China between 2015 and 2016 for the presence of rat pegivirus (RPgV) by PCR. Among the 314 serum samples from murine rodents (Rattus norvegicus, Rattus tanezumi, and Rattus losea) and house shrews (Suncus murinus), 21.66% (68/314) tested positive for RPgV. Out of these, 23.81% (62/219) of samples from R. norvegicus tested positive, which was significantly higher than that for the other species: 7.69% (1/13), 5.88% (2/34), and 6.25% (3/48) for R. tanezumi, R. losea, and S. murinus, respectively (χ2=18.91, P<0.001). Phylogenetic analysis revealed clustering of viral sequences in the main rodent clade. Analysis of the 3 near-full-length genome sequences of RPgV obtained in this study showed that these viruses exhibited mean nucleic acid and amino acid identities of 94.1% and 98.5% with Chinese RPgV strains, and 90.3 and 97.1% with an RPgV strain from the USA, respectively. This study provides novel insights into the geographic distribution of rodent pegiviruses in China, and identifies potential animal hosts for future studies of these pegiviruses.