In this second article we will look at how the coronavirus virus infects us and causes the disease we know as Covid-19. We already know that coughs and sneezes from an infected person can spread millions of viral particles within droplets into the air and anyone coming in contact with them can become infected by inhaling just a few hundred such particles. It is also easy to touch a surface which has the viral particles on it and then to touch your mouth, nose or eyes allowing the virus to enter your body. That is why washing your hands frequently and social distancing are so important in disease prevention.
But now let’s look at the virus in more detail and see what mechanisms it uses to make us ill. The virus is not a living thinking enemy. It is a simple strand of Ribonucleic Acid or RNA. It has one purpose in life and that is to reproduce. Although it is not complicated, it does carry everything it needs within that strand to carry out its mission.
Many of you will already have seen images and illustrations of what the virus looks like. It appears spherical in shape with spikes sticking out of it. These spikes look like little hammers or crowns and this is where its gets its name; corona is another word for crown. These spikes are crucial in how the virus infects and reproduces itself. But it is also its “Achilles’ Heel” which we will discuss later. So what is its method of reproduction?
Once inside our body the virus is looking to invade our cells and reproduce itself. The throat is a favoured place but the nose will also serve its purpose. It is looking for cells which have on their surface an enzyme called ACE2. This enzyme is very useful in controlling our blood pressure but in this particular scenario, it is a weak spot in our cell’s defences. The enzymes stick up out of the cell and it just so happens that the spikes on the virus fit nicely into them, so that it can lock onto the cell. This action allows the virus to enter the cell and the real problems begin.
A cell has the ability to manufacture a range of things that the body may need. But when the virus enters, it gives the host cell a new set of instructions; it tells it to produce numerous copies of itself. These are then released out of the cell and these new virus particles move on to infect more cells. That in very simple terms is how the virus reproduces and spreads to other parts of the body.
However, the body has a number of defenses standing by which will attempt to slow up the spread and then to find a way to kill off the invading virus. This is our immune system and I shall discuss this in the next article.