The term “hepatitis” refers to an inflammatory condition of the liver and can be due to different possible causes, including toxic substances, such as alcohol or certain drugs and autoimmune diseases.
However, hepatitis viruses are the most common cause of hepatitis around the world. If left untreated, the condition can be self-limiting or can develop scarring of the liver (cirrhosis) or progress to fibrosis or liver cancer.
Viral hepatitis is one of the biggest global health threats of our time and the main viral infections of the liver that are classified as hepatitis include hepatitis A, B, C, D, and E. Some of the symptoms are similar, but they have different treatments:
Hepatitis A, sometimes called Hep A is a viral liver disease that can cause mild to severe illness and is caused by a small, non-enveloped hepatotropic virus named Hepatovirus A (HAV). The virus spreads by the fecal–oral route and is transmitted through ingestion of contaminated food and water or through direct contact with an infectious person. Most people who are infected recover completely with no permanent liver damage. However, although rare, hepatitis A can cause death in some people.
There are no specific medicines to cure infection with hepatitis A but recovery from symptoms following infection may take several weeks or months and normally gets better on its own.
Vaccines against hepatitis A are available, being effective in around 95% of cases and lasting for at least fifteen years after vaccination and possibly a person’s entire life. Vaccination against hepatitis A is recommended if you are travelling to countries where there are poor levels of sanitation and hygiene.
Hepatitis B or Hep B is an infection of the liver caused by a virus that spreads through blood and body fluids. Hepatitis B infections is caused by an enveloped DNA virus named hepatitis B virus (HBV).
In general, the virus is most commonly transmitted from mother to child during birth and delivery, as well as through contact with blood or other body fluids, such as blood, vaginal secretions, or semen, containing the hepatitis B virus.
Hepatitis B virus can can cause both acute and chronic infections. Most people recover in 6 months. However, in a long-term infection could lead to liver damage and be very serious, leading to cirrhosis and liver cancer.
Currently there is no cure for hepatitis B infection but medications can help keep the virus under control and stop it damaging your liver. Fortunately, the hepatitis B vaccine is a safe and effective vaccine that is recommended for all infants at birth, giving protection against the hepatitis B virus.
Hepatitis C or Hep C is the most common type of viral hepatitis and is caused by an enveloped, positive-sense single-stranded RNA virus named hepatitis C virus (HCV).
Hepatitis C is transmitted through direct contact with infected body fluids, typically through injection drug use and sexual contact, being one of the most common bloodborne viral infections in the United States.
About 15 to 25 percent of people with the virus clear it without treatment. However, chronic hepatitis C is long-term and can lead to permanent liver scarring (cirrhosis) or liver cancer.
Currently there is currently no hepatitis C vaccine. However, hepatitis C infection can be treated with medicines that stop the virus multiplying inside the body. In addition, new treatments are available that can cure over 95 per cent of people who take them for eight to 12 weeks with few side effects.
Hepatitis D (hepatitis delta) is a is a serious liver disease contracted through direct contact with infected blood that is caused by the hepatitis D virus (HDV), a small spherical enveloped virusoid.
Hepatitis D virus requires hepatitis B virus for its replication because it requires an envelope protein which is synthesised by the hepatitis B virus to enable it to infect liver cells. Therefore, it only affects people who are already infected with hepatitis B.
Patients who already have chronic hepatitis B infection can acquire hepatitis D virus infection at the same time as they acquire the hepatitis B infection, or at a later time. There is currently no cure or vaccine for hepatitis D, but it can be prevented using hepatitis B vaccines before being already infected with hepatitis B virus. In combination, infection of both, hepatitis B virus and hepatitis D virus, is very difficult to treat.
Hepatitis E is inflammation of the liver caused by infection with a positive-sense, single-stranded, non-enveloped, RNA virus name hepatitis E virus (HEV).
Hepatitis E virus is similar to hepatitis A virus in terms of disease, and mainly occurs in Asia where it is transmitted by contaminated water. Most people with hepatitis E get better within a few months. Usually it doesn’t lead to long-term illness or liver damage and rarely develops into a very severe disease that is fatal in about 2%. However, infection with hepatitis E virus can be very dangerous for anyone with weak immune systems, including elderly people and pregnant women.
In addition, a new Hepatitis G virus (HGV) was recently discovered and is under investigation, being its role in causing disease in humans is unclear.