Lesions in transplacentally induced toxoplasmosis in goats.

Fifteen pregnant does were inoculated orally with 10 to 1,000 oocysts of the GT-1 strain of Toxoplasma gondii. Two does were euthanatized on postinoculation days (PID) 10 and 14, and the remaining 13 does aborted or delivered kids transplacentally infected with T gondii on PID 9 to 65. Tissues of all 34 fetuses or kids from the inoculated does were examined for gross and microscopic lesions. Placental necrosis and encephalomyelitis were the most prominent lesions. Toxoplasma gondii invaded the fetal placenta between PID 9 and 11 and invaded fetal tissues 2 to 3 days later. Necrosis attributed to toxoplasmosis, confined to cotyledons, was found in all placentas examined on PID 18. Encephalomyelitis was found in most fetuses or kids between PID 30 and 65. Lesions in fetal tissues were sparse. Because T gondii is rarely found in lesions, histologic examination of the fetal tissues is not likely to help in diagnosing every case of transplacentally induced toxoplasmosis in goats.