Summary and Explanation
The Severe Acute Respiratory Syndrome 2 virus (SARS-CoV-2) is abetacoronavirus first isolated in Wuhan, China, in late 2019. The virushas a 29.8 kbp genome,containing instructions for the membrane,envelope, nucleocapsid, and spike glycoprotein. The spike proteins arecleaved by TMPRSS2 serine protease, and then bind to the ACE2 orCD147 to enter the cell. The Receptor Binding Domain of the Spikeprotein binds tighter to the ACE2 receptor than the similar spike proteinof the SARS virus isolated in 2003.
The SARS-2 virus has been shown to infect the tracheal and lungepithelium, gastrointestinal tract, and olfactory neuron, brain, bonemarrow and possibly other organs. Cough, fever, and trouble breathingare the main symptoms, although gastrointestinal distress, fatigue, andneurological distress are also common. Severe symptoms are more likelyto appear in patients with advanced age and/or preexistingcardiovascular disease or diabetes. The virus has a 2-11 dayincubationperiod and mortalityrate around 2.5%. Severe symptoms include diffusealveolar damage in the lungs, hyaline membrane formation,microthrombi in the lungs, heart, and brain, and extreme inflammationas“cytokine storms” that flood the body with cytokines (elevated 1L1,IL-6, IL-8, and TNFa among others) and immune cells (especially CD4+,CD8+ T cells and CD68+ and CD163+ Macrophages).