Zika Virus Infection at Different Pregnancy Stages: Anatomopathological Findings, Target Cells and Viral Persistence in Placental Tissues

Lucia de Noronha; Camila Zanluca; Marion Burger; Andreia Akemi Suzukawa; Marina Azevedo; Patricia Z. Rebutini; Iolanda Maria Novadzki; Laurina Setsuko Tanabe; Mayra Marinho Presibella; Claudia Nunes Duarte dos Santos

The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. . https://doi.org/10.1101/370528 doi: bioRxiv preprint Eight of the 23 third trimester human placental tissue samples exhibited pathological features in routine H&E-stained sections (whereas placentas without pathological signs were observed in the remaining 15 cases). The most prevalent alteration was delayed villous maturation with additional stromal changes, such as hyperplasia of HCs (75%), as shown in Table 2 and Figures 1B, 1C and 1E. Of the nine cases exhibiting pathological signs in the H&E staining, five were associated with congenital disorders (55.6%), and one evolved to a spontaneous abortion (first trimester placenta, case LRV/15 572). In the remaining 15 cases, no pathological evidence was observed in the H&E sections, but three of these cases presented with congenital disorders (20%) (Tables 1 and 2). Of the six cases with villous immaturity, four had a congenital disorder diagnosed at birth (66.7%), two had intrauterine fetal death (Table 1) , one had acute funisitis, and one had umbilical artery agenesis (Table 2 ). Morphometric analysis of the placentas from women infected during the third trimester of pregnancy confirmed the villous immaturity and hyperplasia of HCs ( Figure 2 ). Syncytial knots and sprouts were quantified to demonstrate disorders of villus maturation, and a higher number of sprouts was detected in the ZIKV-infected group than in the control group (p<0.05) ( Figure 2B ). Villi and CD163+ HCs were measured to evaluate hyperplasia of HCs. Compared to the placentas in the control group, the placentas from women infected with ZIKV during the third trimester showed increased numbers of HCs (hyperplasia) ( Figure Figure 3D ). ZIKV infection of this sample was confirmed by RT-qPCR using RNA extracted from a FFPE tissue core corresponding to a villitis area (Noronha et al., 2016) .