Fig. 1. : pathological findings and immunohistochemistry reactions in placental tissues. (A) Histological section of case 1 immunostained by the conventional immunohistochemistry technique, omitting the primary antibody, which was used as a negative control. We observed chronic placentitis (TORCH type) with chronic villous inflammation (histiocytic-predominant villitis - arrow), edema and trophoblastic epithelial lesions (arrow head) as compared to normal villous tissue (dashed arrow). There was an increase in villous Hofbauer cells and villous stromal lymphohistiocytic cells. (B) Histological section of case 1 immunostained with a non-related anti-Chikungunya virus monoclonal antibody as the primary antibody, which was used as a negative control. We observed the same features observed in A (arrow shows histiocytic-predominant villitis, arrow head shows non lesional trophoblastic epithelial cells and dashed arrow shows normal villi). (C-D) Histological section of case 1 immunostained with the anti-flavivirus monoclonal antibody 4G2. Chronic placentitis (TORCH-type) was observed with immunopositivity in Hofbauer cells (arrow) and some histiocytes in the intervillous spaces (dashed arrow). There was no immunopositivity in the trophoblastic epithelium (arrow head).