Research Note: Complete genome cloning and genetic evolution analysis of four Cherry Valley duck circovirus strains in China in 2022

In recent years, with the expansion of duck breeding industry in China, the infection rate of DuCV duck circovirus (DuCV) in duck and the mixed infection rate of DuCV with other diseases increased significantly, which seriously endanger the development of duck breeding industry. To study the epidemic status of duck circovirus in China, analyze the virus's genetics and evolution, and establish a foundation for scientific prevention and control of duck circovirus, our laboratory collected four disease materials preliminarily diagnosed as duck circovirus infections. Conventional PCR was used to amplify four strains of duck circovirus with a full length of 1993bp, and their sequences were compared and analyzed. The analysis showed that the four DuCVs had typical circovirus characteristics, including three major ORFs: ORFV1 (Rep protein), ORFC1 (Cap protein), ORFC2 (apoptosis-related protein), and a stem ring structure. The four strains were compared with 22 other reference strains, and the results revealed that all four strains belonged to the DuCV-I type represented by the German strain AY228555. Furthermore, the homology between the four DuCVs and the reference strains was up to 98.6%, which help us to understand the genotype and genetic variation of DuCV in these regions and provide a reference for the prevention and control of DuCV.