Causes

Causes of hepatitis C infection are in most cases transmission of the virus via blood contact. This can be due to a lack of hygiene standards for tattoos, piercings or the use of syringes and needles (especially in the drug scene), blood products (blood transfusions), organ transplants or dialysis. Transfusions through needle-stick injuries or other blood contacts between hepatitis C infected persons and medical personnel are also possible.

In addition, there is a low residual risk of virus transmission via semen or breast milk of a person infected with hepatitis C. Transmission of the virus from an infected pregnant woman to the unborn child is about 5% in a normal, complication-free birth. After infection, the virus multiplies within the liver cells and is subsequently released into the blood. As a result, the virus can then spread and multiply unchecked throughout the newborn’s body.

Pathogen and transmission

The hepatitis C pathogen belongs to the Flaviviridae family and is an RNA virus. There are 6 different subgroups of the hepatitis C virus (HCV). In Germany, the types 1,2,3 occur most frequently.

In Africa, on the other hand, type 4 is more common. The most important difference between these subtypes is their response to interferon therapy. Types 2 and 3 respond better to this therapy than the others.

Humans are the only possible host for HCV, i.e. only humans contract the virus. The transmission routes cannot always be traced. However, people who have a lot of contact with blood and blood products belong to the largest risk group.

This includes people in need of a transfusion, people on dialysis, i.v. drug addicts, people after a needlestick injury such as tattoos and piercings on contaminated instruments, or medical personnel who handle the blood of infected persons carelessly. In very rare cases, sexual transmission has been described.

Transmission of the virus from mother to child is estimated to be about 5% in a normal birth. The hepatitis C virus is an RNA virus of which 6 genotypes have been identified so far. In addition, the hepatitis C virus can be further divided into about 100 subtypes.

The respective genotypes show differences in the genetic material. Known are the genotypes 1a, 1b, 2a, 2b, 3a, 3b, 4, 5 and 6. In Europe and North America mainly the genotypes 1-3 occur, genotype 1 has a share of almost 80% in Germany.

In Africa, genotype 4 is the most common, and the different genotypes are based on a difference in genetic makeup. Therefore the different genotypes show different characteristics in their response to different drugs. Genotype 1b, for example, is more resistant to interferon therapy than other types.

The genotype of the hepatitis C virus determines the type and duration of therapy. Furthermore, some genotypes are more aggressive than others. For example, types 1 and 3 are associated with more severe damage and an increased risk of liver cirrhosis and liver cancer. Once infected with a certain hepatitis C genotype, infection with another genotype is still possible.