RESUMO
Histopathological changes and placental transmission were studied in the late stages of pregnancy in mice infected with a strain of Trypanosoma cruzi, isolated from a Myotis nigricans nigricans bat. Large amastigote nests were observed in uterine muscles, as well as in decidual and endothelial placental cells. In addition, persistent coagulative and fibrotic vascular degeneration was observed. Large amastigote burdens were found in giant cells, spongioblasts and endothelial cells within the labyrinthine layer. Transplacental transmission was confirmed in 30% of the fetuses examined, in which amastigote nests were seen only in striated muscle. During the acute phase, intrauterine development was impaired as the result of parasitic invasion of the placenta, and fetal mortality rose to 10%.