Genetic and In Vitro Characteristics of a Porcine Circovirus Type 3 Isolate from Northeast China

Porcine circovirus 3 (PCV3) is an emerging virus first discovered in the United States in 2015, and since then, PCV3 has been found in many regions of the world, including America, Asia, and Europe. Although several PCV3 investigations have been carried out, there is a lack of knowledge regarding the pathogenicity of PCV3, mostly due to the limited number of PCV3 isolates that are readily available. In this study, PCV3-DB-1 was isolated in PK-15 cells and characterized in vitro. Electron microscopy revealed the presence of PCV-like particles, and in situ hybridization RNA analysis demonstrated the replication of PCV3 in PK-15 cell culture. Based on phylogenetic analysis of PCV3 isolates from the Heilongjiang province of China, PCV3-DB-1 with 24 alanine and 27 lysine in the Cap protein was originally isolated and determined to belong to the clade PCV3a.