Study of the efficacy of an inactivated virus vaccine against porcine parvovirus.

The efficacy of an inactivated virus vaccine against porcine parvovirus has been studied by immunizing 4 sows during pregnancy. A parvovirus virulent strain has been inoculated to these sows and to two other unvaccinated sows used as controls. The infection was performed between the 52nd and the 57th day of gestation. In the litters born from the vaccinated sows, 82% of the piglets were alive and normal. Neither PPV antibodies nor antigen could be revealed in the stillborn fetuses born from the 4 vaccinated sows. Reversely, only 9.5% of the piglets born from the 2 unvaccinated sows were alive at birth, although they were probably infected during pregnancy. In total, 86% of fetuses in these 2 litters were mummified. A field study allowed to show that the double vaccination antibodies induced, persisted with constant titers for, at least, 13 months. Moreover, the reproductive performance of 413 gilts, vaccinated twice before mating, were not affected by this treatment.