| Abstract: | PCV 3 is an emerging swine virus associated with porcine dermatitis and nephropathy syndrome (PDNS ), reproductive failure, respiratory diseases and systematic inflammation. Although first identified in 2015, the earliest case has been traced back to 2009 in the United States. In China, PCV 3 infection was first detected in 2015, but little information has been available about its occurrence and prevalence there before 2015. In this study, 200 porcine clinical samples collected from 20 provinces, five autonomous regions and four municipalities between 1990 and 1999 were analysed for PCV 3 infection by PCR . Results showed that 6.5% of the porcine samples collected from eight provinces and one autonomous region were PCV 3 positive, with the earliest cases occurring in 1996. Nucleotide sequence analysis showed that PCV 3 strains obtained in this study shared 96.6%–99.7% and 97.1%–99.4% sequence identity at the ORF 2 gene and genome levels with all available reference strains from China and other countries, indicating the high genetic stability of PCV 3 over the past 20 years. |
