Pathogen and transmission
Pathogen and transmission: The hepatitis B pathogen belongs to the family of Hepadnaviridae. The structure of the virus particle is of great importance for the diagnosis and for the course of the infection. The hepatitis B virus consists of several antigenically active components.
Antigenically active means that the human body recognizes these structures as foreign and can form specific antibodies against them ().The structure and the virus components are: The infected person excretes the virus in almost all body fluids, such as blood, saliva, urine, semen, vaginal mucus, tears, cerebral fluid (liquor), and in breast milk. These potential sources of infection result in parenteral (through the gastrointestinal tract), perinatal (between the 28th week of pregnancy until the end of the first week of life) and transmissible infections. The most common transmission route worldwide is from the infected mother to the child (perinatal).
Today, in the “western world”, this route of infection has been reduced by prophylactic measures. On the other hand, other transmission paths predominate, with various risk groups being particularly affected. These include patients requiring transfusions (recipients of blood and blood products), patients requiring dialysis, medical personnel, persons with frequent and unprotected sexual intercourse (promiscuity) and i.v.
drug addicts. It is estimated that more than half of all infections are transmitted in Germany. The infectivity of the virus is enormously high, it even exceeds the infectivity of HIV.
Already 1μl blood can serve as a source of infection. An important feature of the hepatitis B virus is the fact that HBV multiplies its “genes” (DNA, genome) with the help of a special enzyme, reverse transcriptase, and can incorporate them into the DNA of the healthy liver cell (hepatocyte). HBV is therefore closely related to the actual retroviruses (e.g. :HIV).
and transmission of hepatitis B
- Surface envelope => HBs antigen (“s” as surface=surface)
- Core of circular HBV-DNA
- DNA polymerase (DNA multiplication enzyme)
- Hepatitis B core antigen => HBc antigen (“core” like core)
- Hepatitis B envelope antigen => HBe antigen (“envelope” as in envelope)
The incubation period of hepatitis B is between 45 and 180 days. On average, the time between infection and onset of symptoms is about 60 to 120 days. In about 1/3 of the cases, however, the disease runs asymptomatic, so that no incubation period can be specified here.
In extremely rare cases, e.g. when the body is in a strong immune deficiency (immunosuppression), the infection can flare up again. Such an immunodeficient condition exists when strong immunosuppressive drugs are administered after organ transplants, after chemotherapy or in the case of a late-stage HIV infection. Special case: Hepatitis D virus infection The hepatitis D virus can only become infectious with the help of hepatitis B.
The hepatitis D virus (HDV) has a defect and can only multiply with the help of the hepatitis B virus surface antigen (HBs-Ag). Hepatitis B virus infection (HBV) is made considerably more difficult by the additional second virus. It is possible to become infected with HBV and HDV simultaneously, but HDV can also be a graft to HBV. Vaccination against hepatitis B virus always protects against hepatitis D virus as well.
