virus

A virus is a microbe, i.e. a very small organism, that infects a cell and often causes infectious diseases such as chicken pox, influenza or covid-19. However, other viruses can be beneficial and protect us. There are more than 5000 different viruses, which can be grouped into families, such as the coronavirus family. Viruses can take many different forms. Scientists consider viruses to be on the borderline of living organisms because they cannot reproduce or move on their own, as they must always enter a living cell in order to reproduce.

A virus is not a bacterium, which is another type of microbe. Viruses are a hundred times smaller than normal bacteria and the main difference is that bacteria are made up of a cell, whereas viruses live inside a cell.

Viruses are not typically coloured, but if we see them coloured, it is because we stain them so that we can see them more clearly under a microscope.