Abstract
Porcine circoviruses (PCV) belong to the family Circoviridae, genus Circovirus. Currently, four species are known: PCV1, PCV2, PCV3, and PCV4. PCV1 is considered a non-pathogenic virus. PCV3 and PCV4 have recently been described - although their pathogenic importance remains to be clarified, while PCV2 is associated with several diseases collectively referred to as porcine circovirus dise…