An inactivated, oil-emulsion vaccine for the prevention of porcine parvovirus-induced reproductive failure

Pig fetuses inoculated at 45 days gestation with virulent porcine parvovirus (PPV) were harvested 10 days later. Virus was extracted, inactivated with binary ethylenimine and the antigen suspension emulsified with mineral oil adjuvant. One dose of this vaccine, or two doses with a 14 day interval, stimulated high and long lasting serum antibody titres in gilts. Vaccination caused no clinical reactions and lesions at injection sites were minor. Vaccination of seronegative gilts at 40 days gestation caused no adverse effects on fetuses. Six gilts which had been vaccinated five to nine weeks before mating were challenged intravenously with live, virulent PPV at 40 days gestation. At 98 days gestation 78 out of 84 (93 per cent) fetuses were alive and normal and no evidence of PPV infection was found in the six dead (mummified) fetuses. In four unvaccinated gilts similarly challenged with PPV at 40 days gestation only five out of 51 (10 per cent) fetuses survived to 98 days gestation and the virus was detected in 41 of the 46 dead (mummified) fetuses. This vaccine appears to be safe and effective for prevention of PPV-induced fetal loss in gilts.