Reproductive failure associated with porcine circovirus type 2 in gilts

A 4800-sow farrow-to-wean farm with a new on-site gilt-development facility experienced an 8-week period of increased abortions and mummified pigs in gilt litters. Replacement gilts previously supplied from an external source at 24 weeks of age were not affected. Fetuses from 10 aborted litters were necropsied. Placenta, umbilical cord, stomach contents, thoracic fluid, heart, lung, liver, spleen, kidney, and thymus, and whole blood from dams, were collected. Histopathological evaluation demonstrated nonsuppurative myocardial mononuclear inflammation with extensive multifocal myocardial mineralization. In all litters submitted, porcine circovirus type 2 (PCV2) antigen was identified by immunohistochemistry in fetal heart lesions. Pooled fetal lung tissue was positive for PCV2 by polymerase chain reaction (PCR). Fetal lung tissue and thoracic fluid were PCR-negative for porcine reproductive and respiratory syndrome virus (PRRSV). Fetal lung tissue was negative for parvovirus by fluorescent antibody testing. Fetal kidneys were culture-negative for Leptospira and other pathogenic bacteria. Gilt sera were negative for PRRSV by PCR and negative for antibodies to PRRSV by ELISA. Serological testing of gilts demonstrated low antibody titers to parvovirus and six serovars of Leptospira interrogans. In addition, PCV2-associated enteritis, pneumonia, and systemic infections were diagnosed in five 20-week-old gilts during the period of reproductive failure.