ACE2 and COVID-19: For example, the cynomolgus macaque and ferrets can simulate human mild COVID-19 (Rockx et al., 2020a; Shi et al., 2020); Human ACE2 (hACE2) transgenic mice can simulate human severe, lethal COVID-19 Bao et al. (2020); And Golden Syrian hamsters can be used to study the pathogenesis of moderate-to-severe COVID-19 in humans (Muñoz-Fontela et al., 2020; Bestion et al., 2022; Qiu et al., 2022).