Fig 1.

ZIKV proliferation is decreased by co-infection with JEV on BHK-21 cells. BHK-21 cells were co-infected with ZIKV (MOI of 5) and JEV (A) strain SA14-14-2 (MOI of 5) or (B) strain P3 (MOI of 1). ZIKV and JEV RNA levels were determined by qRT-PCR at 30 h post infection. Compared to single-infected cells, ZIKV RNA levels were significantly reduced (P < 0.01) in co-infected cells. Levels of JEV RNA in co-infected cells were not statistically different than in cells infected with JEV alone. (C) Viral protein expression in single- and co-infected BHK-21 cells. JEV NS1 protein (red) and ZIKV NS2B-NS3 protease protein (green) were detected by indirect immunofluorescence assay (IFA) at 30 h post infection. Nuclei were stained with 4'-6-diamidino-2-phenylindole (DAPI) (blue). JEV and ZIKV proteins were detected in single-infected cells. In co-infected cells, the number of JEV-positive cells did not observably change, while the number of ZIKV-infected cells was greatly reduced. ns, non-significant. P > 0.05; **, very significant, P < 0.01.