Fig. 2.

It is the timeline of coronavirus that was first discovered in human history. The 229E was first founded in 1966, and it was the first invented coronavirus of which seven ones could infect people. Secondly is OC43, which was isolated from patients with cold. The next one is SARS, the outbreak of SARS was discovered in November 2002 and ended in 2003. In the same year, NL63 was detected using the VIDISCA and PCR method. In 2004, HKU1 was reported by HKU and named. Seven years later, an outbreak was founded in the Middle East, caused by a novel coronavirus named MERS-CoV. In 2018, researchers surprisingly analyzed nasal swabs from 301 pneumonia patients treated in a hospital in East Malaysia. It was found that eight patients, except for one child, were infected with the newly discovered coronavirus, which the researchers of the study named CCOV-HuPn-2018. In December 2019, a case of SARS-CoV-2 was reported in Asia. Nevertheless, there is also evidence in NEJM that revealed that the 2019-nCoV infection could be diagnosed in Germany and transmitted outside to Asia. The authentic original place of SARS-CoV-2 is still unknown.