Coronaviruses (CoVs) are a viruses group that co-infects humans and other vertebrate animals. CoV infections affect the respiratory, gastrointestinal, liver, and central nervous systems of humans, livestock, birds, bats, mice, and many other wild animals [Wang, et.al, 2006, Ge].
The source of unexplained pneumonia was first discovered in Wuhan in Dec, 2019, and SARS-CoV-2, a new coronavirus, was isolated from the respiratory epithelium of patients. It belongs to a new evolutionary branch within the CoV. On Feb. 11th, 2020, the new coronavirus was officially renamed “SARS-CoV-2" from “2019-nCoV" [Gorbalenya et.al,2020]. The disease caused by SARS-CoV-2 was called “coronavirus disease 2019" (COVID-19) [Who 2020].