Reproductive failure associated with porcine parvovirus and possible porcine circovirus type 2 co-infection

A 2400-sow multi-site commercial herd experienced an outbreak of reproductive failure characterized by a dramatic increase in mummified fetuses, primarily in primiparous animals. Multiple samples of mummified and stillborn fetuses, placenta, and weak liveborn pigs were submitted to the diagnostic laboratory. Diagnostic testing for porcine parvovirus (PPV) in tissue sections was positive by virus isolation and direct fluorescent antibody. Antibodies to PPV were detected by indirect fluorescent antibody (IFA) and competitive enzyme-linked immunosorbent assay. Porcine circovirus type 2 (PCV2) was also diagnosed by polymerase chain reaction, and antibodies were detected by IFA. Mummified fetuses in gilt litters rose acutely from 3.9% to 31.5%, but in multiparous animals during the same time period the rate rose only slightly, from 3.2% to 4.2%. At its peak, the mummified-fetus rate in gut litters reached 61.0%. Mid- to late-term gilt abortions also increased significantly during the affected time period. Although all animals were vaccinated for PPV during the isolation-acclimation period, it still became an apparent cause of severe reproductive failure. The role of PCV2 in this case is unclear, but PCV2 may have contributed to the severity of the outbreak as a co-infection or by interfering with the effectiveness of the PPV vaccine.