As Hans Nauwynck explains in his previously published articles "Understanding viruses from the cell to the farm" and "What is driving PCV2 evolution?", PCV2 replicates in the lymphoblasts, the immune-stimulated lymphocytes.
In a high health animal that is not exposed to other infections, PCV2 has little power. It will replicate at low levels. But, when multiple coinfections generate a strong stimulation of the immune response including the creation of lymphoblasts, PCV2 can replicate in a higher degree, and the impact of the virus will become more destructive.

