How many coronaviruses cause human disease, and which of them are zoonoses?
Six coronaviruses may cause human disease. Two of them are zoonoses: the severe acute respiratory syndrome coronavirus (SARS-CoV1) and Middle East respiratory syndrome coronavirus (MERS-CoV), which may be fatal. The other four viruses all cause the common cold.
How the SARS-CoV-2 act at the cellular level?
The SARS-CoV-2 virus affects its cellular entry via attachment of its a.k.a. S protein to the angiotensin-converting enzyme II (ACER2) receptor. This fusion between the envelope and the host cell membranes aid viral entry into the host cell. This receptor is on the lung epithelium's alveolar cells, which contributes to diffuse alveolar damage and may explain the pathologic mechanism of GGO, consolidation, and the respiratory symptoms' development as the most typical presentation of COVID-19.
How is the transmission of COVID-19?
Its transmission originates from animals, but now COVID-19 is considered an indirect zoonosis, as its transmission is primarily human-to-human. This disease may be transmitted similarly to the common cold via contact with droplets of infected individuals' upper respiratory tract secretions. Aerosol transmission of SARS-CoV-2 may occur by aerosol-generating procedures in healthcare facilities, as well as there may be aerosol transmission produced by talking, singing, coughing, and expiration. Fomite transmission is another way to disseminate the disease, which explains the care taken on regular handwashing and regular cleaning of surfaces exposed to droplets/aerosols containing virion particles.
What are the primary findings of COVID-19 on chest radiograph and CT?
The primary findings of COVID-19 on chest radiograph and CT are those of atypical pneumonia or organizing pneumonia.
Can a chest radiograph or CT present without pulmonary abnormalities in patients with suspected COVID-19 pneumonia?
Patients may have a normal chest radiograph or CT when mild or early in the disease course.
There are bilateral, multiple rounded consolidations with surrounding ground-glass opacities and the intra/interlobular septal thickening - crazy-paving pattern. The lesions are mostly in the peripheral and posterior parts of the lungs.
No pleural effusion, neither enlarged mediastinal lymph nodes.
This patient tested positive for coronavirus disease-19 and had the CT imaging features for the peak stage (stage 3) COVID-19 pneumonia.