Abstract
Porcine circoviruses (PCV) belong to the family Circoviridae, genus Circovirus. PCV1 is considered to be a non-pathogenic virus, while PCV2 is associated with several diseases collectively referred to as porcine circovirus diseases (PCVD). When the commercial vaccines based on the PCV2a genotype appeared, disease control became effective, so vaccination is a widely used control and preven…