1 Etiology

In the initial Diagnosis and Treatment Plan of Corona Virus Disease 2019(Tentative First Edition), the description of coronavirus etiology was based on the understanding of physicochemical properties of previously discovered coronaviruses. With the continuously in-depth research, the second edition added “coronaviruses cannot be effectively inactivated by chlorhexidine”, as well asadded in the fourth edition “2019-nCoV belongs to the genus b, with envelope,round or elliptic and often pleomorphic form, and 60–140 nm in diameter. Its genetic characteristics are obviously different from those of SARSr-CoV and MERSr-CoV.The homology between 2019-nCoV and bat-SL-CoVZC45 is over 85%.” and “when cultured in vitro, 2019-nCoV can be found in human respiratory epithelial cells after about 96 hours, while it takes about 6 days to isolate and culture VeroE6 and Huh-7 cell lines”, as well as “coronaviruses are sensitive to ult raviolet rays”.