The Invasion And Infection of Coronavirus
There are thousands of coronaviruses have been found, there are four of them that are related to the influenza, and the other two have caused epidemics that are sufficient to warn the human public health crisis. They included the SARS epidemic in 2002, which caused approximately 770 deaths worldwide. And MERS in 2012, which caused about 800 deaths worldwide. Among them, SARS disappeared bizarrely a year after the epidemic, while MERS still exists in the human world.
The new coronavirus (SARS-CoV-2) caused a more deadly pandemic, partly because once the virus infects a person, it often goes undetected for a long time. People with SARS coronavirus will not begin to spread the virus until 24 to 36 hours after symptoms such as fever and dry cough. People who feel unwell can have time to isolate and avoid infecting other people. However, people with COVID-19 can spread the virus before the symptoms become obvious. During this period, the infected person will not feel unwell, so they will be continuously working, commuting, and releasing the coronavirus from the body to the surroundings. This virus can stay in the body for a long time without being detected, partly because the protein produced by the virus’s genetic mechanism delays our immune system from issuing an alarm, then the normal cells die when the virus reproduces in secret. When the immune system finally hears the warning signal, it will cause an excessive reaction instead, which will kill the healthy cells that should have been protected.
Generally, the SARS-CoV-2 virus particles that have been inhaled into the nasal cavity or oral cavity of humans are about 100 nanometers in diameter. Such a small particle can only be seen through an electron microscope, it is near-spherical coated in the lipoproteins, which can slide into the human protective spiral-like viral RNA (the red part in the picture) – a molecule that holds the viral genetic code. The part called S protein (the deep orange coronal protrusion in the picture) will form surface protrusions, which can grab cells more than a hundred times the size of the human body. Therefore, such virions sneak into human cells and cause infection, and the structural protein – N, M and E proteins can move into the cell to help the formation of new virions.