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What causes hepatitis B in children?
Medical expert of the article
Last reviewed: 04.07.2025
Causes of Hepatitis B in Children
The causative agent of hepatitis B is a DNA-containing virus from the hepadnavirus family (from the Greek hepar - liver and English DNA - DNA).
Hepatitis B virus (Dane particles) is a spherical formation with a diameter of 42 nm, consisting of an electron-dense core (nucleocapsid) with a diameter of 27 nm and an outer shell with a thickness of 7-8 nm. In the center of the nucleocapsid is the virus genome, represented by double-stranded DNA.
The virus contains 3 antigens that are essential for laboratory diagnostics of the disease:
- HBcAg is a nuclear, core antigen of protein nature;
- HBeAg - transformed HBcAg (infectivity antigen);
- HBsAg is a surface (Australian) antigen that forms the outer shell of the Dane particle.
The hepatitis B virus is very resistant to high and low temperatures. At a temperature of 100 °C, the virus dies in 2-10 minutes; at room temperature it survives for 3-6 months, in the refrigerator - 6-12 months, in frozen form - up to 20 years; in dried plasma - 25 years. The virus is extremely resistant to the effects of chemical factors: a 1-2% chloramine solution kills the virus in 2 hours, a 1.5% formalin solution - in 7 days. The virus is resistant to lyophilization, exposure to ether, ultraviolet rays, acids, etc. When autoclaved (120 °C), the activity of the virus is completely suppressed only after 5 minutes, and when exposed to dry heat (160 °C) - after 2 hours.
[ Pathogenesis of hepatitis B in children
In the mechanism of development of the pathological process in hepatitis B, several leading links can be identified:
- introduction of the pathogen - infection;
- fixation on the hepatocyte and penetration into the cell;
- reproduction and release of the virus onto the surface of the hepatocyte, as well as into the blood;
- activation of immune responses aimed at eliminating the pathogen; o damage to extrahepatic organs and systems;
- formation of immunity, release from the pathogen, recovery.