Coronavirus is so called because its morphology has a crown-like periphery under electron microscopy. It is widespread in nature and its natural hosts include domestic animals, poultry, rodents, and wild mammals. Middle East Respiratory Syndrome (MERS), Severe Acute Respiratory Syndrome (SARS), and the novel pneumonia outbreak in late 2019 are all caused by coronaviruses. (2019 novel coronavirus) Classification of coronaviruses Coronaviruses belong to the order Cepoviridae, family Coronaviridae, subfamily Coronaviridae, genus Coronavirus. in 2014, the International Committee on Virological Classification divided the family Coronaviridae into four genera, namely alpha, beta, gamma and delta genera. 1, Alpha coronavirus genus: the representative species is A coronavirus 1, this genus can be divided into 2 groups. Group 1 includes porcine infectious gastroenteritis coronavirus, feline intestinal coronavirus, canine coronavirus, etc. Group 2 includes human coronavirus 229E, long-winged bat coronavirus HKU1, etc.; 2. Beta coronavirus genus: the representative species is mouse coronavirus, and this genus can be divided into 4 groups. The genus Gamma coronavirus: the representative species is avian coronavirus, including chicken infectious bronchitis virus, duck coronavirus, etc.; 4. The genus Delta coronavirus: the representative species is the nightingale coronavirus HKU11, including the pictorial coronavirus, porcine butyl coronavirus, etc. (SARS virus) 7 coronaviruses that can cause disease in humans 2019 novel coronavirus, namely “2019-nCoV”, was discovered due to Wuhan viral pneumonia in 2019, which is a brand new coronavirus. Prior to this, there were six coronaviruses that could cause disease in humans: 1. SARS-CoV: highly pathogenic to humans, SARS ravaged the world from winter 2002 to spring 2003, causing severe acute respiratory syndrome; 2. Classical human coronavirus 229E: identified in 2004, can cause infection in young children, immunocompromised people and the elderly, with some people showing symptoms of colds and diarrhea, and has been 3. Human coronavirus OC43: a close relative of classical human coronavirus 229E, with similar pathogenicity, identified in 2004; 4. HCoV-NL63: discovered in 2004, mainly manifests as lower respiratory tract infection, asthma and capillary bronchitis, reported worldwide; 5. winter, associated with upper and lower respiratory tract infections, and most of the symptoms disappear over time, with a small proportion of people infected with severe disease such as pneumonia, capillary bronchitis, and acute exacerbation of asthma; 6. HERS-CoV: i.e., Middle East Respiratory Syndrome coronavirus, discovered in 2012, can cause severe respiratory tract infections. (MERS virus under the microscope) Current issues regarding coronaviruses and their harmful effects on human infections have raised a high level of alarm. However, further research is needed on the direct or indirect transmission pathways between diseased animals and humans, whether there is a possibility of mass transmission between humans, and the mutation of coronaviruses in animals to appear as cross-species transmission. China is actively developing effective antiviral drugs and preventive vaccines in order to implement effective preventive and surveillance measures. Source: Dr. You Lai References State Key Laboratory of Infectious Disease Diagnosis and Treatment, Center for Infectious Diseases, The First Hospital of Zhejiang University School of Medicine Ma Yilin. Progress in the study of the characteristics of coronaviruses and their pathogenicity[J]. Chinese Journal of Clinical Infectious Diseases,2018,11(4):305-315.