Lesions in fetal pigs with transplacentally-induced toxoplasmosis.

Two sows (Nos. 1, 2) were each fed 1,000 Toxoplasma gondii oocysts. Sow No. 1 was fed oocysts at 60 day of gestation and was euthanatized 49 days later. Sow No. 2 was fed oocysts at day 45 of gestation and euthanatized 62 days later. Sow No. 1 had eight dead fetuses of which one was mummified and unsuitable for histologic study. Sow No. 2 had 11 fetuses, of which four fetuses were mummified and unsuitable for histologic examination, two fetuses were dead and five were live. Lesions and Toxoplasma parasites were identified in seven fetuses from sow No. 1 and three fetuses from sow No. 2. No lesions were found in four fetuses from sow No. 2. Toxoplasma gondii was present in trophoblasts and produced areas of necrosis of the chorioallantois with focal placental separation. The predominant lesions were necrotizing placentitis, non-suppurative encephalomyelitis, and myocardial degeneration, necrosis and mineralization. Numerous tachyzoites were seen in trophoblast cells lining areolae in placenta.