Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, or 2019-nCoV) is an enveloped non-segmented positive-sense RNA virus. It is the cause of coronavirus disease 2019 (COVID-19), which is contagious in humans. The new coronavirus belongs to the beta coronavirus of the genus β, which has an envelope, the particles are round or oval, often polymorphic, and the diameter is 60-140nm. Its genetic characteristics are significantly different from SARSr-CoV and MERSr-CoV. Current research shows that it has more than 85% homology with bat SARS-like coronavirus (bat-SL- CoVZC45). In vitro isolation and culture, 2019-nCoV can be found in human respiratory epithelial cells in about 96 hours, while it takes about 6 days to isolate and culture in Vero E6 and Huh-7 cell lines. Based on current epidemiological investigations, the incubation period is generally 7 days, with a maximum of 14 days.
Main symptoms of infection include fever, fatigue, and dry cough. A few patients have symptoms such as nasal congestion, runny nose, and diarrhea. In severe cases, dyspnea occurs more than a week later. Besides, acute respiratory distress syndrome, septic shock, difficult to correct metabolic acidosis, and coagulation dysfunction develop rapidly. Current detection methods for new coronaviruses include nucleic acid detection and antibody detection. New coronavirus nucleic acids can be detected in throat swabs, sputum, lower respiratory tract secretions, and blood. Serum antibody testing helps confirm the infection status of a case.