Hepatitis B virus
Hepatitis B virus (HBV) refers to hepadnavirus. Similar viruses cause hepatitis in marmots, ground squirrels and
Chinese ducks, which makes it possible to use these animals as experimental models in the development of medicines and vaccines.
The hepatitis B virus is very stable in the external environment, has a high infectivity. If the immune response is kept, a person with persistent hepatitis B develops a permanent lifelong immunity.
In the environment, the hepatitis B virus can persist for about a week – even in a dry and inconspicuous bloodstain, on the razor’s edge, the end of the needle.
How common is hepatitis B?
Hepatitis B affects more than 2 million people worldwide, the number of infected carriers of the virus is 350 million. Three quarters of the Earth’s inhabitants live in regions with a high incidence.
Annually, about 4 million cases of acute hepatitis B occur, and 1 million people die from the effects of chronic hepatitis B (25% of HBV carriers).
But in recent years, thanks to the widespread ubiquity of hepatitis B vaccination, there has been an encouraging trend towards a decrease in the incidence of this infection.
The mechanism of development of infection due to the hepatitis B virus
The mechanism of transmission of the hepatitis B virus is hematogenous, i.e. through the blood. Infection occurs from a patient with acute or chronic hepatitis B when infected blood enters the body of a healthy person.
The blood of a hepatitis B virus infected becomes viral long before the onset of the first symptoms of the disease, and retains these properties to varying degrees throughout the duration of a chronic infection.
It is possible to transmit the infection sexually and from mother to child in childbirth. The HBV virus itself is large and does not pass through the placenta.
Through damage to the skin and mucous membranes, the HBV virus enters with a blood flow into the liver. The hepatitis B virus penetrates into liver cells–hepatocytes and begins to multiply.
Genetic material of the virus – viral DNA is collected in the nucleus of the hepatocyte cell, and the enveloped proteins are synthesized in the cytoplasm. Then viral chamstice – virions undergo complete assembly and leave the cell, hitting neighboring ones.