Where did novel coronavirus come from? Where is the source? It is not clear at present. There is no unified statement about who patient 0 is. But what is certain is that COVID-19 is a new acute respiratory infectious disease, which is highly contagious. It is contagious in the incubation period and within five days after onset. The sources of infection are patients infected with COVID-19 and asymptomatic infected people. The incubation period is 1- 14 days, mostly 3-7 days, and individual patients can reach more than 20 days.

Viral characteristics

According to the existing case data, novel coronavirus is mainly characterized by fever, dry cough and fatigue, and a few patients are accompanied by symptoms of upper respiratory tract and digestive tract such as nasal congestion, runny nose and diarrhea. Most severe cases have dyspnea after 1 week, and severe cases rapidly progress to acute respiratory distress syndrome, septic shock, metabolic acidosis that is difficult to correct, bleeding and coagulation dysfunction and multiple organ failure. It is worth noting that severe and critically ill patients may have moderate to low fever or even no obvious fever during the course of the disease.

Mild patients only show low fever and mild fatigue. , and no pneumonia. Judging from the cases admitted at present, most patients have recovered well, and a few patients are in critical condition. The prognosis of the elderly and those with chronic basic diseases is poor. The symptoms of children's cases are relatively mild. The main routes of transmission are respiratory droplet transmission and contact transmission. In addition, contact with articles contaminated by COVID-19 will also be infected, and people are generally susceptible. The main clinical manifestations are fever, fatigue and dry cough, and some patients have a sense of smell.