PCV2 is a ubiquitous virus in domestic pig and wild boar, both in countries where porcine circovirus diseases (PCVDs) have or have not been described. PCV2 was associated with postweaning multisystemic wasting syndrome (PMWS) by mid 90s, and since then it has also been linked to a number of diseases and conditions such as reproductive failure, porcine dermatitis and nephropathy syndrome (PDNS), porcine respiratory disease complex (PRDC) and proliferative necrotizing pneumonia.