What is a virus?

Viruses are these tiny, invisible structures that cause infections. They make us sick. There are millions of viruses in our environment but only about 5000 have been identified by scientists. The ones you may have heard of are the Human Immunodeficiency Virus or HIV and the Novel Coronavirus or Covid-19.

What do viruses look like?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) illustration, created at the Centers for Disease Control and Prevention (CDC)

Do you think that a virus is some creepy, crawly thing? It is not. A virus is a non-living thing. It is invisible to the human eye. A virus is one hundred times smaller than a bacteria, which is why most viruses cannot be seen even under a microscope.

So how does a virus make someone sick?

To make someone sick, a virus needs a host. The host is that living creature inside which the virus can multiply and spread, and generally make a nuisance of itself. The host could be a human body, an animal, or even as tiny as a bacteria. First, the virus needs to enter the living body. It could enter through blood or saliva or even sneeze droplets. Next, the virus turns that living body into a virus photocopying machine. Once infected by a virus, a living body starts creating multiple copies of the virus. Before you know it, that body is bursting with viruses and is sick.

And how does a virus spread?

To spread from a body full of a virus to a body that does not have the virus, the virus needs a way. Imagine an elevator, taking the virus from one body to the next. In the case of HIV, the elevator that carries the virus from one body to the next is blood, saliva or semen. Let us take the example of a person infected with HIV. If they have a bleed, and they touch someone else who also has a cut in their skin, and their bloods mix, then the HIV virus could enter the second person. Some viruses, like Covid-19, travel in the tiny droplets that come out of our bodies when we cough or sneeze. When an infected person coughs or sneezes, then droplets of fluid carry the virus out. If you are close enough, then the virus will go up your nose and into your lungs. These types of viruses are called respiratory viruses, because they affect our breathing. Which is why doctors say, don’t touch your face, wear a mask, and wash your hands with soap.