For hematoxylin and eosin (H&E) staining, placentas were embedded in paraffin blocks and sectioned at 5 μm after overnight fixation in 4% paraformaldehyde. On these sections, a qualitative observation was carried out to examine the general structure of decidua and labyrinth regions. Fluorescent staining on placentas was performed on frozen sections of 10 μm obtained from cryostat. Sections were prepared with the same protocol used for brain immunostaining and were incubated overnight with mouse anti-J2. After PBS wash, sections were incubated with goat anti-mouse Alexa Fluor 546 (1:500; AP192SA6) (Thermo Fisher Scientific, USA) and IB4, an isolectin for vasculature staining. In addition, we used a mouse anti-NS1 antibody (1:100; EA88) (Thermo Fisher Scientific, USA) to detect ZIKV in the placenta. Following incubation of the primary antibody, a goat anti-mouse Alexa Fluor 488 (1:1000, A28175) (Thermo Fisher Scientific, USA) was used.