Detection and genetic characterization of porcine pegivirus from pigs in China

Porcine pegiviruses (PPgV) have been first discovered in serum samples from domestic pigs in Germany in 2016 and then in the USA in 2018. To date, there is no documentation with respect to the presence of PPgVs in domestic pigs in China. Herein, we attempted to determine the presence and prevalence of PPgV in China and its genetic characterization. In this study, 469 sera were tested and 34 (7.25%) were positive for PPgV. An ascending trend of the positive rate for PPgV was observed from suckling piglets (1.61%) to nursing piglets (1.85%), finishing pigs (6.56%), and sows (11.34%). The complete genome sequence of a representative strain of PPgV, PPgV_GDCH2017, and the complete E2 gene of 17 PPgV isolates discovered in this study was determined. Sequence analysis indicated that PPgV_GDCH2017 was highly related to other PPgVs with nucleotide and amino acid identities ranging from 87.3 to 97.4% and 94.6–99.3%, respectively, in the complete coding region. Phylogenetic analyses demonstrated that the PPgV_GDCH2017 discovered in this study was closely related to the PPgVs from the USA and clustered in the same genus with pegiviruses from other hosts. The topology of the phylogenetic tree based on the complete E2 gene was consistent with that based on the complete genome of PPgV. Further studies on pathogenicity and pathogenesis of PPgVs are needed.