Before learning about How Coronavirus kills the most important part is how it spreads ? scientist have not found any proof that coronavirus is spreading through the air from one person's body to another. But in special case if the virus or droplets stays afloat on the dust particles, as there are many dust particles around us . Then, it can easily enter the body of the person passing by inhaling the dust particles. But this is a rare case.
So by this we can say that it is spread by the water droplets or saliva droplets. when a Infected person sneezes he releases thousands of saliva droplets . now let me tell you as per the study one droplets contains lakhs of Coronavirus particles and can spread up to one meter and that to very quickly . After coming out from the infected person if not on the dust particles they stick on the other surfaces like coronavirus can stay for 96 hours on Glass , 72 hours on Steel and 24 hours on Cardboard . When a non infected person touches this surfaces and then touches there eyes nose or mouth the virus gets inside the body . That's why they say we should always maintain distance about one meter and always wear a mask and Sanitize things and hands regularly.
So as we understand what and how it spreads now lets understand how it affect our body once it enters our body . As of we know that our body is made up of cells , our body is made up of trillions of cells. Now when Coronavirus enter our body it attack only the cells on the boundary of lungs because the lungs boundary cells have Ace2 receptors and coronavirus outer surface presents the spike protein to explain better let us assume that the spike protein on the virus surface is the key and the Ace2 receptors on the lungs cells are lock . Now the cell membrane of the lung cells is semi-permeable so the particle present nearby cant enter the cell but some particles can enter like nutrients can go in the cells and the waste material from the cell can come out. so now when Coronavirus get lock on the Ace2 receptors of the cell the cell thinks its a friendly thing and allow the virus to enter the cell . Now once the Coronavirus enter the cell it quickly transfer the RNA in the cell and will high jack the cell and command the cell to make copies of coronavirus as the RNA of the coronavirus have the instruction of making copies. now in few days the cell been high jacked will make the lakhs of copies of coronavirus and in the end due to less space the cell will burst .
After the coronavirus entering the body and spreading the infection and destroying the first cell this whole process take 2 - 10 days and this period of time is known as the Incubation Period this is the reason the coronavirus spread with this speed as some time the person affected is in incubation period and you never know as he will show no symptoms.
Now when the first cell will burst and the virus will start spreading our innate immune system will get activated and will start fighting the virus we have heard that we get fever once we get affected by virus this is because the immune system of our body will create a hostile environment in body which increase the temperature of the body cause fever .
Some people suffer from the breathing problems this is because when the cells are been destroyed in body and the immune system keep on fighting with the virus this creates the puss in the alveoli of the lungs alveoli is the only place where the CO2(Carbon dioxide) from body goes out and O2 (Oxygen) comes in side the body but if the puss is created then there is a problem of passing of both CO2 and O2 which cause the breathing problems and some time become the cause of death.
In the end the saliva drop is 98% made of water so if the virus would have been killed by water it would have been died in our saliva but its not the case so we suggest to wash hands with not only water but soap . Use of Sanitizer is must as it destroy the outer layer of the virus. Maintain 1 meter distance and always wear a mask while in public places .