Hepatitis C is an inflammation of the liver caused by a specific virus called the hepatitis C virus (HCV). The word "hepatitis" is derived from two Latin segments: "hepat" refers to the liver, and "itis", meaning inflammation. The term "hepatitis" is not specific for a particular cause of the inflammation, as hepatitis can be caused by reactions to medications, toxic drugs, poisons, alcohol, allergic reactions, autoimmune diseases (when the body attacks itself by mistake) and a variety of viruses. The most common viruses that specifically cause hepatitis include
- hepatitis A virus,
- hepatitis B virus, and
- hepatitis C virus. Other hepatitis viruses also exist and cause a small number of infections. Additionally, other viruses can cause hepatitis even though they are not specifically "hepatitis viruses". These most commonly include Epstein Barr Virus (EBV), the cause of mononucleosis, and cytomegalovirus (CMV), which causes a variety of illnesses in different parts of the body, especially in patients whose immune function is depressed due to steroids, chemotherapy for cancer, and HIV/AIDS.
There are two stages of hepatitis C. The acute (early) phase occurs soon after infection. Most people have no symptoms at this stage. Roughly 75% - 85% of individuals infected go on to develop a chronic infection. At this second, chronic stage, there may be no symptoms for years or decades. Eventually, if left untreated, most people with chronic hepatitis C will become symptomatic with progressive liver disease.
There are multiple subtypes of hepatitis C, called genotypes. These include genotypes 1a, 1b, 2, 3, 4, 5 and 6. The differences between the genotypes has an important impact on how we treat HCV infection (type of medication used, dosing and duration of therapy)