Hepatitis C virus

Hepatitis C virus is the organism that causes hepatitis C. It is an enveloped virus, meaning it is wrapped in a layer of fat, and its genetic information is a strand of RNA, not DNA. It belongs to the family Flaviviridae.

Its target is the hepatocyte, the liver cell. It gets in by endocytosis, which is when the cell wraps around it and pulls it inside. Once inside, it assembles a replication complex, the machinery it uses to copy itself, whose central enzyme is a polymerase called NS5B. It settles into the liver cell and puts it to work copying the virus. One important point: this virus does not integrate into the genome of the cell that hosts it; it does not insert itself into the chromosomes.

The problem is that most people do not clear it on their own. Between 80 and 85 percent of people with acute infection cannot get rid of the virus, and the infection turns chronic. Over the years that chronic infection can lead to cirrhosis, which is scarring of the liver, and to hepatocellular carcinoma, the cancer that arises from the liver itself.