Furthermore, there are still unanswered questions about SARS, e.g., ‘Why did the first SARS case occur in Guangdong Province, but all the human-ACE2-using SARSr-CoVs were found in Yunnan Province?’ and ’Why does R. sinicus in certain areas carry human-ACE2-using SARSr-CoVs but no other Rhinolophus species carry the same viruses?’ Above all, further extensive surveillance of SARSr-CoVs in China is warranted. Here, ACE2 is linked to severe acute respiratory syndrome.