What are the transmission routes of hepatitis B?
In principle, infection with hepatitis B is possible through any body fluid, since the virus, due to its small size, can in principle enter the production sites of all secretions. The most common route of infection worldwide is the transmission of the virus from mother to child during the birth process: after such an infection, a chronic disease almost always develops in the child. In order to understand the various transmission pathways of the hepatitis B virus, it is best to first gain an overview of the occurrence of the virus in the body: the highest concentration of the virus is found in the bloodstream. Depending on the number of virus particles detected by the diagnostic tests, one can then draw conclusions about the presence of infectious virus particles in other body fluids: If a particularly large number of particles are found in the blood, it is a so-called highly viral carrier, in which the presence of particles in other secretions is very likely. Accordingly, the body secretions of such a person are highly likely to be infectious.
Sexual transmission
The hepatitis B virus often occurs not only in the blood but also in body fluids such as vaginal secretions or sperm. Infection with the hepatitis B virus through sexual intercourse is therefore possible. Whether virus particles are actually present in the body fluids depends on the viral load of the respective infected person.
If the blood contains a lot of virus particles (high viral load), it is likely that other body fluids contain infectious virus particles. If there are few viruses in the blood or a low viral load, infection through sexual intercourse is less likely, but still possible. The pathogens enter the body and the bloodstream through tiny injuries in the skin or the mucous membrane, which cannot be seen with the eye. As with many other sexually transmitted diseases, sperm is also more infectious than vaginal secretions. This may explain why there are still many homosexual men among the reported cases of hepatitis B infection.
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