INVESTIGATIONS ON INFECTIOUS AGENTS FOR ABORTION AND STILLBIRTH IN SWINE IN SWITZERLAND

Fetuses and placentae of 171 cases of porcine abortion, stillbirth and mummification were examined for pathological lesions, bacterial infections and PPV (porcine parvovirus) infection. Furthermore IgG (immunogrobulin G) levels were determined in fetal body fluids. Selected maternal sera were tested for antibodies against Leptospira, Aujeszky's disease and hog cholera. PPV infection was diagnosed in 29.2 % of all cases. Bacterial abortion was diagnosed in 8.2 %. Indications for an infectious agent were demonstrated in about 10 % of the cases. The etiology of the abortion could not be identified in 52 %. Inflammatory alterations in association with the isolation of bacteria consisted of neutrophilic infiltration and necrosis and were of particular value to differentiate bacterial contamination from infection. Infiltrations of mononuclear leucocytes in brain, leptomeninx, kidney or myocard were observed in about 50 % of the fetuses with PPV infection. IgG levels were consistently elevated in fetuses serologically positive for PPV, bur: also in two fetuses, where no infectious agent could be identified.