Pediatric Drug Nitazoxanide: A Potential Choice for Control of Zika

Cao, Rui-Yuan; Xu, Yong-fen; Zhang, Tian-Hong; Yang, Jing-Jing; Yuan, Ye; Hao, Pei; Shi, Yi; Zhong, Jin; Zhong, Wu

Pediatric clinical drug nitazoxanide and its bioactive metabolite tizoxanide were tested at serial concentrations for their ability to inhibit ZIKV proliferation in Vero cells by plaque assay (Supplementary Figure 1) . As shown in the figure, these 2 drugs inhibit virus titer in a dose-dependent manner. Nitazoxanide reduced infectious ZIKV particles by >100-fold at 10 μM, whereas tizoxanide completely abolished supernatant ZIKV proliferation at 10 μM. This inhibition was further demonstrated by immunofluorescence assay detecting the envelope protein expression ( Figure 1A ) and by Western bot detecting the ZIKV capsid protein ( Figure 1B) . No cytotoxicity was observed for these 2 drugs under assay concentrations ( Figure 1C ). We further investigated the kinetics of ZIKV propagation in the presence of these 2 drugs (Supplementary Figure 2) , and obvious inhibition was observed. In addition, both drugs inhibited intracellular ZIKV RNA production in a dose-dependent manner under different multiplicity of infections (MOIs) (Supplementary Figure 3) . To verify whether nitazoxanide and tizoxanide could inhibit ZIKV in human-derived cells, we performed antiviral experiments in A549 cells, and we found that both drugs could inhibit ZIKV infection in a dose-dependent manner under nontoxic doses ( Figure 1D , toxicity data not shown).