ACE2 and COVID-19: Two groups showed that the viral RNA could be excreted from nose and throat in the absence of clinical signs in SARS-CoV-2-infected macaques, and pulmonary infiltrates and histological lesions could also be observed.7,8 By using transgenic mice bearing human ACE2, Shi and Qin groups found that the infected mice generated typical interstitial pneumonia and pathology that were similar to those of COVID-19 patients.9–11 Ferrets were also used as a potential animal model.