Porcine Circovirus type 2 (PCV2) associated diseases

To date, PCV2 infection in domestic pigs and wild boars is widespread worldwide and has been associated with several syndromes, collectively called porcine circovirus diseases (PCVD). They include: postweaning multisystemic wasting syndrome (PMWS), porcine dermatitis and nephropathy (PDNS), and, in some cases, porcine respiratory disease complex (PRDC). PMWS only is considered to have the higher economic impact on pig farms. It is considered a multifactorial disease in which PCV2, in combination with other factors, is able to determine the clinical signs of the disease. Its main clinical signs were observed in piglets and in fattening pigs; wasting is considered to be the major one. This syndrome is diagnosed by detection of histopathological lesions typical of lymphoid tissues and the simultaneous presence of PCV2 antigen. PDNS is a disease characterized by immuno-complexes, fibrino-necrotizing glomerulonephritis and necrotizing vasculitis. These lesions are associated with PCV2, but to date the pathogenetic role of the virus in the development of such lesions has not yet been demonstrated. As to PRDC, the identification of PCV2 in the lungs suggested that the virus could play a kay role in determining it, especially in the presence of a low prevalence of other viral pathogens and/or bacterial. Currently, the clinical signs of PRDC are highly variable and nonspecific. Three vaccines are now available in Europe. Two of them are to be used for piglets only, while the third one is lincensed for both sows and piglets.