CT Imaging Features of Patients Infected with 2019 Novel Coronavirus

Coronavirus disease 2019 (COVID-19) is an acute, infectious pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection after full genetic testing [1, 2]. Coronaviruses are enveloped segmental positive RNA viruses belonging to the Coronaviridae family and the Nidovirales order. Coronaviruses are widespread among humans and other mammals, and can cause severe respiratory, intestinal, liver, and nervous system diseases [3]. SARS-CoV-2 belongs to the genus coronavirus, and its genetic characteristics are significantly different from severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERSCoV) and are more similar to bat SARSlike coronaviruses (bat-SL-CoV ZC45 and bat-SL-CoV ZXC21) [4–6]. The confirmed human-to-human transmission of SARSCoV-2 [7–10] makes it a highly infectious virus, resulting in the ongoing global pandemic. People are generally susceptible, normally with an incubation period of 1–14 days [8], but the case fatality rate is higher in the elderly and people with underlying diseases [11, 12]. Respiratory droplets and contact transmission are the main routes of infection [13]. The virus can also be spread by aerosols, especially in a relatively closed environment. Furthermore, recent research has suggested that the virus can be spread through feces and urine [14, 15]. Patients infected with SARS-CoV-2 usually have a history of epidemiological exposure, and a small number of patients show signs of throat congestion and tonsil swelling when infected. COVID-19 patients mainly present symptoms of lower respiratory tract infection, such as dry cough, fever, dyspnea, sputum production, etc. Besides, there is the possibility of accompanying symptoms of fatigue, myalgia or arthralgia, headache and chills [16–18]. In severe cases, SARS-CoV-2 can cause acute respiratory distress syndrome (ARDS) and sepsis. Asymptomatic infected people might also become the source of infection.