Viruses are tiny particles that cause various diseases in humans, animals and plants. The word "particles" may seem strange, but let's see why we use it. Viruses are so small that they can filter through even the finest filters. Their tiny size does not allow them to be seen under an ordinary microscope, therefore, when studying viruses, scientists are forced to use photographs.


Unlike bacteria, they cannot be diluted in sugar syrup: they grow and multiply only in the presence of living matter. As parasites, they are completely dependent on the organism in which they are located. Due to the fact that they are so small and it is extremely difficult to artificially create conditions for their growth, many researchers are inclined to think that viruses are not living organisms at all.

Viruses are sources of diseases, many of which are known to everyone. By acting on different organs of the body, each group of viruses causes different types of diseases.

Many skin diseases, such as chickenpox, measles are the result of the activity of one group of viruses. Another group of viruses is the cause of the central nervous system diseases: rabies, brain inflammation, infantile paralysis. The third one affects the internal organs and causes yellow fever, flu, common cold and so well knowm coronavirus