Hepatitis D is a defective virus that requires hepatitis B to replicate and is only found with hepatitis B co-infection. In adults, hepatitis B infection is most commonly self-limiting, with less than 5% progressing to chronic state, and 20 to 30% of those chronically infected developing cirrhosis or liver cancer. Infection in infants and children frequently leads to chronic infection.Unlike hepatitis B, most cases of hepatitis C lead to chronic infection. Hepatitis C is the second most common cause of cirrhosis in the US (second to alcoholic hepatitis). In the 1970s and 1980s, blood transfusions were a major factor in spreading hepatitis C virus. Since widespread screening of blood products for hepatitis C began in 1992, the risk of acquiring hepatitis C from a blood transfusion has decreased from approximately 10% in the 1970s to 1 in 2 million currently. Parasitic hepatitis
Parasites can also infect the liver and activate the immune response, resulting in symptoms of acute hepatitis with increased serum IgE (though chronic hepatitis is possible with chronic infections). Of the protozoans, Trypanosoma cruzi, Leishmania species, and the malaria-causing Plasmodium species all can cause liver inflammation. Another protozoan, Entamoeba histolytica, causes hepatitis with distinct liver abscesses.Of the worms, the cestode Echinococcus granulosus, also known as the dog tapeworm, infects the liver and forms characteristic hepatic hydatid cysts. The liver flukes Fasciola hepatica and Clonorchis sinensis live in the bile ducts and cause progressive hepatitis and liver fibrosis.
There is some evidence of hepatitis E infection of animals, serving as a reservoir for human infection. Alcoholic hepatitis
Alcoholic hepatitis (AH) in its severe form has a one-month mortality as high as 50%. Most people who develop AH are men but women are at higher risk of developing AH and its complications likely secondary to high body fat and differences in alcohol metabolism. Other contributing factors include younger age <60, binge pattern drinking, poor nutritional status, obesity and hepatitis C co-infection. It is estimated that as much as 20% of people with AH are also infected with hepatitis C.  In this population, the presence of hepatitis C virus leads to more severe disease with faster progression to cirrhosis, hepatocellular carcinoma and increased mortality. Obesity increases the likelihood of progression to cirrhosis in cases of alcoholic hepatitis. It is estimated that 70% of people who have AH will progress to cirrhosis. Non-alcoholic steatohepatitis
Non-alcoholic steatohepatitis (NASH) is projected to become the top reason for liver transplantation in the United States by 2020, supplanting chronic liver disease due to hepatitis C.  About 20–45% of the U.S. population have NAFLD and 6% have NASH. The estimated prevalence of NASH in the world is 3–5%. Of NASH patients who develop cirrhosis, about 2% per year will likely progress to hepatocellular carcinoma. Worldwide, the estimated prevalence of hepatocellular carcinoma related to NAFLD is 15–30%. NASH is thought to be the primary cause of cirrhosis in approximately 25% of patients in the United States, representing 1–2% of the general population.