Hepatitis is an infectious liver disease that is either congenital or acquired through a virus or a bacterium. .
The best known are the hepatitis viruses, as a lot of educational work is done in this regard.
It is generally known that if you become infected with a hepatitis virus, you can fall ill with chronic liver inflammation.
What many people are not aware of is that a hepatitis B virus is also an oncovirus, which means that it can not only cause liver inflammation, but also cancer.
Hepatitis B virus (HBV):
The hepatitis B virus (HBV) is a partially double-stranded DNA virus from the family Hepadnaviridae.
The virus multiplies in the hepatocytes, and during this process the HBV antigen is usually released into the bloodstream.
The hepatitis B virus is not cytopathogenic, so it does not affect the function of liver cells, even though it is produced in large quantities.
The virus attaches itself as a solid component in the DNA of the liver, so it cannot be completely eliminated even with treatment.
After acute infection, there is a dormant state, but the virus does not disappear completely and can be reactivated at any time should immunodeficiency occur.
There are 8 known genotypes, with only type 1 being common worldwide (but mainly in the United States, Europe and China). In Japan and Taiwan, mainly types 2 and 4 can be classified, in South America type 3. In Africa, types 5, 6, 7 and 8 occur most frequently.
Transmission:
The virus is transmitted via blood or other body fluids.
Infection can therefore occur during sexual contact (vaginal, anal or oral), but also during injuries, or during drug consumption due to the use of syringes that have already been used.
In addition to blood, the viruses can be detected in body fluids such as urine, saliva, seminal fluid, lacrimal secretions, bile, but they can also be detected in breast milk.
Therefore, especially in developing countries, many babies are still infected with the virus through breastfeeding.
The degree of infectivity depends on how high the viral load is in the body.
A highly viraemic carrier can also pass on the virus in daily life, through small inadvertencies like a cut while shaving, which can get blood on the razor.
If this is used by someone else, they can become infected through it, as a microscopic wound is enough for the virus to enter.
Course of the disease:
Immediately after entry of the hepatitis B virus, replication occurs.
As soon as the virus has multiplied, the immune system becomes active and tries to fight off the virus.
However, this does not necessarily mean that one has to show symptoms. The infection can also be asymptomatic.
This is called an inapparent course. The immune defence does not lead to any symptoms. The virus disappears again without making itself felt.
The survived infection leads to immunity.
If there is a very strong replication of the virus, the immune system also reacts with a stronger defence, which leads to a symptomatic course.
Similar to a flu-like infection, acute hepatitis B causes fever, aching limbs and fatigue. Symptoms similar to gastritis may also occur, such as nausea, loss of appetite, pressure pain in the right upper abdomen and diarrhoea.
Jaundice may occur, causing the urine to turn dark, the skin and eyes to turn a yellowish colour, and itching. Even with acute hepatitis B, healing and the resulting immunity is possible, but there may also be incomplete defence. If hepatitis B does not heal even after 6 months, it is called a chronic course.
In the case of a strong replication of the virus, immune tolerance can also occur, which means that the patient's own immune system does not fight the virus sufficiently to heal it. If this leads to an inadequate defence against the virus, the patient will develop chronic hepatitis. Chronic hepatitis develops in about 10% of cases.
Why does the hepatitis B virus belong to the oncoviruses?
Because of the long-term consequences of an infection.
If you contract hepatitis B so severely that you suffer a chronic course, cirrhosis of the liver can develop as a consequence.
This is the case in about 12% of chronically ill patients. In 0.5% of cases, liver cirrhosis leads to hepatocellular carcinoma. Patients who carry the hepatitis B virus have a 100-200 times higher risk of developing liver cancer.
If the infection occurred in childhood (for example, through breast milk), the risk of developing cancer is particularly high.
Liver carcinoma most often develops as a consequence of liver cirrhosis and usually occurs about 20-30 years after infection.
How can the virus be prevented?
The best way to protect yourself from infection with the hepatitis B virus is to get vaccinated.
The vaccination is not bound to any age, so it can be administered at any age, both in infancy and adulthood.
There are various vaccination schedules, which differ depending on the age at which vaccination is given.
For infants, 4 doses are needed, administered at 0, 1, 2 and 12 months of age. If the vaccination is given as a combination vaccination with the vaccine for hepatitis A, 2 doses are needed if the first vaccination was given before the age of 16. In the case of a single vaccine, 3 doses are needed, which are injected within 6 months. In principle, vaccination is recommended for everyone, but especially for those who belong to a risk group (e.g. relatives with hepatitis, drug users) or who work in a risky profession (e.g. doctors, nurses, police officers working in a drug environment).
Protected sexual intercourse cannot prevent an infection with absolute certainty, but it can reduce the probability of transmission many times over. Since not only hepatitis but many other diseases can also be transmitted through sexual intercourse, "safe sex" should always be practised anyway.
To protect yourself from infection in the drug environment, it is important to always use new syringes. There are many organisations that dispose of used syringes correctly and provide new syringes to reduce infection on the street.