ACE2 and infection: They are named for the crown-like spikes on their surface, and are classified as alpha, beta, gamma, and delta.8 They affect the respiratory, gastrointestinal and central nervous systems.9 Mechanistically, the CoVs-mediated infection is initiated by the entry of the virus into host cells through binding of the viral spike protein (S-protein) to angiotensin-converting enzyme 2 (ACE2) present in the host (mainly epithelial cells such as pneumocytes and enterocytes).