Favipiravir or ribavirin treatment resulted in reduced ZIKV E protein expression. A549 cells were infected with ZIKV (MOI-5) and treated with either DMSO control (0 M), favipiravir (1, 10, 25, and 50 μM), or ribavirin (1, 10, 25, and 50 μg/mL) for 72 h post infection. The ZIKV envelope (E) protein was immunostained with an anti-pan-flavivirus envelope monoclonal antibody. ZIKV E is indicated in red and cell nuclei are stained blue. The images are representative of three independent experiments. Magnification shown is 400 × and the scale bar represents 20 μm. % ZIKV E-stained cells were calculated and the graph represents an average of three independent experiments. * p < 0.05; *** p < 0.001.