The effect of porcine parvovirus and porcine reproductive and respiratory syndrome virus on porcine reproductive performance

From a worldwide perspective, porcine parvovirus (PPV) and porcine reproduc tive and respiratory syndrome virus (PRRSV) are the most common viral cause s of porcine reproductive failure. A typical epidemic of PPV-induced reprod uctive failure is presented as an increased number of mummified fetuses and sometimes, entire litters are mummified. If infection with PPV is very ear ly in gestation, the number of liveborn pigs may be further reduced as a re sult of embryonic death and resorption. During the acute stage of infection gilts and sows have few, if any, clinical signs, and it is unlikely that P PV is ever the direct cause of abortion. In contrast, a typical epidemic of PRRSV-induced reproductive failure is presented as a broader spectrum of c linical features including abortions, late-term dead fetuses, stillborn pig s, and weakborn pigs. In the later stages of an epidemic, there may also be an increase in the number of mummified fetuses, but their prevalence is li kely to be far less than during an epidemic of PPV-induced reproductive fai lure. During the acute stage of infection with PRRSV, gilts and sows may ha ve few, if any, clinical signs, or they may be severely affected and even d ie. This difference largely reflects the relative Virulence of the strain o f PRRSV causing the epidemic. A timely and reliable laboratory diagnosis of either disease can be made when appropriate tests are performed with appro priate samples. Vaccines are available for prevention of both diseases. Pub lished by Elsevier Science B.V.