The main feature of viruses is their peculiar structure. They have a heredity, which is due to the same structures as other living organisms – nucleic acids. Most viral diseases are acute respiratory viral infections and intestinal catarrh.
There are viruses that infect the nervous system, such as poliomyelitis, rabies, tick-borne encephalitis. Some viruses contribute to the development of skin diseases, for example, pemphigus, the formation of warts, damage to internal organs, for example, the liver with viral hepatitis, the walls of blood vessels. AIDS, rabies, and almost extinct smallpox also belong to viral diseases.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.