Antiviral Drugs Against Severe Fever With Thrombocytopenia Syndrome Virus Infection

Takayama-Ito, Mutsuyo; Saijo, Masayuki

Amodiaquine is a novel compound that is routinely prescribed as an antimalarial drug is reported to show antiviral effects against ebolavirus (Gignoux et al., 2016; Sakurai et al., 2018) , dengue virus (Boonyasuppayakorn et al., 2014) , and zika virus (Balasubramanian et al., 2017) . The mechanism of inhibitory activity of amodiaquine against malaria and those viruses remains unclear. Baba et al. (2017) investigated the effect of amodiaquine and other halogen molecules (fluorine, bromine, and iodine) against the replication of SFTSV in vitro. All the derivatives also displayed anti-SFTSV activity, and the IC 50 was 36.6, 31.1, and 15.6 µM for fluorine bromine, and iodine, respectively ( Table 1) . Among the compounds tested, amodiaquine was identified as a selective inhibitor against SFTSV replication. The CC 50 and the IC 50 of amodiaquine was >100 and 19.1 µM, respectively. The IC 50 of amodiaquine was lower than those of ribavirin (40.1 µM) and favipiravir (25.0 µM).