Porcine Circovirus-2 and PMWS: Facts and Speculation on this New Infectious Disease of Swine

Porcine circovirus-2 is a newly described viral pathogen responsible for postweaning multisystemic wasting syndrome (PMWS), reproductive failures and possibly other diseases of swine such as porcine dermatitis/nephropathy syndrome (PDNS). Subclinical infection appears to be endemic in swine and expression of clinical disease is dependent upon host and environmental co-factors including stress associated with early weaning, intercurrent infections and immunostimulation. Reproduction of clinical disease in gnotobiotic piglets requires either co-infection with porcine parvovirus (PPV) or immunization with a strong macrophage-targeted adjuvant. Emerging data from the field implicate management practices and early vaccination, particularly against mycoplasma sp., as risk factors for development of PMWS.