Hepatitis is an inflammation of the liver commonly caused by viral infections. but other infections, toxic substances (e.g. alcohol, certain drugs), and autoimmune diseases can also cause hepatitis. Hepatitis can be self-limiting or can progress to fibrosis (scarring), cirrhosis or liver cancer.
There are 5 main hepatitis viruses, referred to as types A, B, C, D and E. Types B and C especially lead to chronic disease in a majority of affected people and, together, are the most common cause of liver cirrhosis and cancer.
Hepatitis A and E are typically caused by ingestion of food or water contaminated by the virus from faecal matter. Hepatitis B, C and D usually occur as a result of parenteral contact (contact with infected body fluids). Common modes of transmission for these viruses include receipt of contaminated blood or blood products, invasive medical procedures using contaminated equipment and for hepatitis B transmission from mother to baby at birth, from family member to child, and also by sexual contact.
Acute infections may be asymptomatic or associated with Jaundice, Dark urine, Fatigue, Nausea and abdominal pain.
Hepatitis A Virus Infections are in many cases mild, with most people making a full recovery and remaining immune from further HAV infections. Hepatitis B Virus spreads mainly through parenteral route and as a Sexually Transmitted Disease(STD). Safe and effective vaccines are available to prevent HBV.
There is no vaccine for Hepatitis C Virus and it mainly spreads through blood and blood products. It can also be an STD, though rarely.
Hepatitis D virus infects only those people who are already affected by HBV. The dual infection of HDV and HBV can result in a more serious disease and worse outcome. Hepatitis B vaccines provide protection from HDV infection.
HEV is a common cause of hepatitis outbreaks in developing parts of the world and is increasingly recognized as an important cause of disease in developed countries. Safe and effective vaccines to prevent HEV infection have been developed but are not widely available.