PPV should be considered in a differential diagnosis of reproductive failure of swine whenever there is evidence of embryonic or fetal death or both. The pathologic sequelae of maternal infection during gestation have been described (see the section on clinical signs). If gilts but not sows are affected, maternal illness is not seen during gestation, there are few or no abortions or fetal developmental anomalies, and other evidence suggests an infectious disease, then a tentative diagnosis of PPV-induced reproductive failure can be made. The relative lack of maternal illness, abortions, and fetal developmental anomalies differentiates PPV from most other infectious causes of reproductive failure. However, a definitive diagnosis requires laboratory support.