Historical data indicated that CoVs, which infect humans by using a specific host protein as a primary receptor, including HCoV-229E (APN), HCoV-NL63 (ACE2), SARS-CoV (ACE2), SARS-CoV-2 (ACE2) and MERS-CoV (DDP4), originated from bats, whereas HCoV-OC43 and HCoV-HKU1, which use Neu5,9Ac2, originated from rodents [255].