Fig. 1
ZIKV infects and replicates in first trimester placental explants. First trimester placental explant tissue cultures (n = 6 patients in duplicate) were infected with ZIKV at 106 or 107 PFU/well and (A) ZIKV RNA genomes quantified by qRT-PCR. Data were log transformed and analysed by Ordinary Two Way ANOVA (* P < 0.05, ** P < 0.01. *** P < 0.005) or (B) infectious ZIKV particles in culture supernatant from infected explant tissues detected by plaque assay. Some explants that were infected at 106 PFU/well did not produce infectious plaques at 72hpi. The 24hpi data represents the viral inoculum, as virus was left on explants for 24 h. This data was not included in subsequent statistical analysis. Data were log transformed and analysed by Ordinary Two-Way ANOVA. (* P < 0.05, **** P < 0.0001). (C) Frozen sections from ZIKV infected explant tissues (96hpi) were stained for ZIKV-Envelope antigen (red), cytokeratin (green) and nuclei (DAPI). Bars represent 100 μm unless otherwise indicated. Images are representative of multiple samples analysed (D). First trimester placental explant tissue cultures (6 patients in duplicate) were infected with DENV and at timepoints indicated DENV RNA genomes quantified by qRT-PCR including in uninfected controls. (E) infectious DENV particles in the culture supernatant from infected explant tissues detected by focus forming assay. All data are means± SE