Prenatal and preweaning deaths caused by pseudorabies virus and porcine parvovirus in a swine herd.

Sequential outbreaks of pseudorabies virus and porcine parvovirus infections were documented at a swine farm in southern Minnesota. Data for the prevalence of mummified fetuses born and the preweaning mortality were recorded over a 3-year-period. The farm was a farrow-to-finish facility, with breeding females housed in 4 groups according to their stage of pregnancy. The herd consisted of approximately 130 breeding females in December 1981, and expanded to 220 females during the 12 months of 1982. Excluding the outbreaks, the mean preweaning mortality was 20.43% (SE 1.59) and the number of mummified fetuses per litter was 0.19 (SE 0.01). An outbreak of porcine parvovirus infection caused the preweaning mortality and number of mummified fetuses to increase to 50% and 4.10 per litter, respectively. Two outbreaks of pseudorabies 27 months apart, caused the preweaning mortality to increase to 95% and 82%, and the number of mummified fetuses to increase to 0.96 and 1.25 mummified fetuses per litter, respectively. The increase in mummification was observed 1 month after the increase in preweaning mortality caused by pseudorabies virus infections, whereas the increase in mummification and preweaning mortality was simultaneous with porcine parvovirus infections.