What is hepatitis?

Hepatitis is an inflammation of the liver (‘itis’ meaning inflammation in ancient Greek, and ‘hepato’ meaning relating to the liver). It can have a number of different causes, including infection (viruses, bacteria, fungi and parasites), drugs and chemicals. One common form of hepatitis is caused by drinking too much alcohol over a long period of time and is referred to as ‘alcoholic hepatitis’. 

Viruses are the most common cause of hepatitis due to infection. The period immediately after infection with a hepatitis virus is called the ‘acute’ phase, and when infection with a hepatitis virus persists for more than six months in a row, it is called the ‘chronic’ phase of infection. There are a number of different viruses that cause hepatitis (hepatitis A, B, C, D and E viruses), but only the hepatitis B, C and D viruses can cause chronic hepatitis infections. 

Hepatitis C is one of the most common viral liver diseases (after hepatitis B) and is caused by the hepatitis C virus (HCV). The hepatitis C virus was identified by researchers in 1989. Before this time, doctors were simply aware of an unknown, blood-borne, infectious disease that they called ‘non-A non-B hepatitis’. This disease was so-called because it caused liver inflammation but was different from the hepatitis A and hepatitis B viruses that were already known. 

Most commonly, hepatitis C is a chronic condition, which means that it can continue to cause liver damage over a long period of time (decades). It can be present for many years without any symptoms at all (asymptomatic) and so is often called a ‘silent epidemic’. In some cases, hepatitis C can remain asymptomatic even after significant liver damage has occurred.

By the time any symptoms appear, someone with hepatitis C can already have advanced liver disease. How quickly liver damage develops depends on how long someone has had hepatitis C, their age at the point of infection, race, lifestyle, whether they have any other infections and whether or not they have received treatment. Typically, men are more likely than women to be infected with hepatitis C, although this difference may be largely attributed to risk factors associated with lifestyle.

Since the discovery of the virus, there have been many advances in hepatitis C research. It is now understood that there are different types of hepatitis C virus, based on genetic variations, and that infections with some of these are unequal in their response to treatment. The different genetic types are called genotypes (for example, genotype 1) and each genotype can also contain a number of subtypes (for example, genotype 1, subtype a).