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What causes hepatitis B in children?
Last reviewed: 23.04.2024
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Causes of hepatitis B in children
The causative agent of hepatitis B is a DNA-containing virus from the family of hepadnaviruses (from the Greek hepar - liver and English DNA - DNA).
Hepatitis B virus (Dana particles) is a spherical formation with a diameter of 42 nm, consisting of an electronically dense core (nucleocapsid) with a diameter of 27 nm and an outer shell 7-8 nm in thickness. In the center of the nucleocapsid is the genome of the virus, represented by double-stranded DNA.
The virus contains 3 antigens, which are of great importance for laboratory diagnosis of the disease:
- HBcAg is a nuclear, core antigen, having a protein nature;
- HBeAg - transformed HBcAg (antigen of infectiousness);
- HBsAg is a superficial (Australian antigen) that forms the outer shell of a Dane particle.
The hepatitis B virus is very resistant to high and low temperatures. At a temperature of 100 ° C, the virus dies after 2-10 minutes; at room temperature is 3-6 months, in the refrigerator - 6-12 months, frozen - up to 20 years; in dried plasma - 25 years. The virus is extremely resistant to chemical factors: 1-2% chloramine solution kills the virus after 2 hours, 1.5% formalin solution - after 7 days. The virus is resistant to lyophilization, the effects of ether, ultraviolet rays, the effect of acids, etc. When autoclavable (120 ° C), the virus is completely inhibited only after 5 minutes, and when exposed to dry heat (160 ° C) after 2 hours.
[The pathogenesis of hepatitis B in children
In the mechanism of development of the pathological process with hepatitis B, several leading links can be distinguished:
- introduction of the pathogen - infection;
- fixation on the hepatocyte and penetration into the cell;
- multiplication and isolation of the virus on the surface of the hepatocyte, and also into the blood;
- inclusion of immune reactions aimed at eliminating the pathogen; o defeat of extrahepatic organs and systems;
- formation of immunity, release from the pathogen, recovery.