Human viruses, viruses and viral diseases, viral diseases

Viral diseases of man - is the result of the impact on his body of the smallest forms of life - viruses.

Viruses and viral diseases are carriers of genetic information - nucleic acid molecules surrounded by a dense protective coat of proteins. Being outside the cell, the viruses show no signs of life and behave like organic particles of polymers. Simple in structure, not having a cellular structure, pathogens can live only in living cells of the human body, animals, plants and in fibroblasts of a chicken embryo. Intruding into the cells of the human body , the virus begins to actively feed on the contents of the cell, which ensures rapid death.

Human viral diseases are divided according to epidemiological characteristics into zooanthroponotic, transmitted to humans from animals, and anthroponous, which only a person can get sick. The main ways in which viral infections are transmitted to a person are:

- food path - viral hepatitis A, E are transmitted with contaminated food and water;

- through the blood or parenteral transmission of fragile viruses, which are rapidly destroyed in the environment. These are viruses of rabies, hepatitis B, HIV, etc. Transmission occurs with unprotected sex, when working with infected surgical instruments and transplacental from mother to child;

- Viral infections of influenza, mumps and chickenpox are transmitted by the respiratory system. This path is most dangerous, since with air viruses are transported to a considerable distance, and can cause epidemics.

Each type of virus in the human body has target organs, which are more suitable for the development of a particular viral infection. By the type of organs affected by viruses, there are different types of viral infections: respiratory, intestinal, affecting the peripheral and central nervous system. Viruses affect the skin and mucous membrane, internal organs, the immune system and blood vessels of the human body.

Viral diseases, the types of their clinical development are divided into acute and chronic.

Disease in the acute form proceeds with rising of temperature, pains in muscles and joints, weakness and change of blood composition. When examining the patient, symptoms of a local nature are also revealed - damage to the brain zones, damage to the liver and mucous membranes of the respiratory tract. Acute diseases are easily amenable to drug treatment. Correctly and timely carrying out of treatment of the patient will prevent transition of illness in the chronic form.

Another picture of the course of the disease in the chronic form of viral infection. The disease usually flows imperceptibly, a person's viral diseases of this nature are not amenable to treatment and can last for a long time, which leads to functional changes in internal organs.

Dangerous infections include latent infection, which can be present for a long time in the patient's body with complete absence of symptoms of a viral disease. It is this kind of infection that can activate and move into an acute form with any influence of an internal or external factor, for example, a decrease in immunity or supercooling of the body.

At the site of infection, infection can be local and generalized.

Human viral diseases are local in nature if the virus multiplies at the site of infection and does not spread through the body. Generalized infections, after primary reproduction at the site of penetration, penetrate further into the blood and spread by blood to various organs.