Hepatitis is inflammation of the liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), poor appetite, vomiting, tiredness, abdominal pain, and diarrhea. Hepatitis is acute if it resolves within six months, and chronic if it lasts longer than six months. Acute hepatitis can resolve on its own, progress to chronic hepatitis, or (rarely) result in acute liver failure. Chronic hepatitis may progress to scarring of the liver (cirrhosis), liver failure, and liver cancer.Hepatitis is most commonly caused by the virus hepatovirus A, B, C, D, and E. Other viruses can also cause liver inflammation, including cytomegalovirus, Epstein–Barr virus, and yellow fever virus. Other common causes of hepatitis include heavy alcohol use, certain medications, toxins, other infections, autoimmune diseases, and non-alcoholic steatohepatitis (NASH). Hepatitis A and E are mainly spread by contaminated food and water. Hepatitis B is mainly sexually transmitted, but may also be passed from mother to baby during pregnancy or childbirth and spread through infected blood. Hepatitis C is commonly spread through infected blood such as may occur during needle sharing by intravenous drug users. Hepatitis D can only infect people already infected with hepatitis B.Hepatitis A, B, and D are preventable with immunization. Medications may be used to treat chronic viral hepatitis. Antiviral medications are recommended in all with chronic hepatitis C, except those with conditions that limit their life expectancy.
Risk of infection is highest among intravenous drug users, people with high-risk sexual behaviors, healthcare workers, people who had multiple transfusions, organ transplant patients, dialysis patients and newborns infected during the birthing process. Close to 780,000 deaths in the world are attributed to hepatitis B. The most endemic regions are in sub-Saharan Africa and East Asia, where as many as 10% of adults are chronic carriers. Carrier rates in developed nations are significantly lower, encompassing less than 1% of the population. In endemic regions, transmission is thought to be associated with exposure during birth and close contact between young infants. Hepatitis C
Chronic hepatitis C is a major cause of liver cirrhosis and hepatocellular carcinoma. It is a common medical reason for liver transplantation due to its severe complications. It is estimated that 130–180 million people in the world are affected by this disease representing a little more than 3% of the world population. In the developing regions of Africa, Asia and South America, prevalence can be as high as 10% of the population. In Egypt, rates of hepatitis C infection as high as 20%  have been documented and are associated with iatrogenic contamination related to schistosomiasis treatment in the 1950s–1980s. Currently in the United States, approximately 3.5 million adults are estimated to be infected. Hepatitis C is particularly prevalent among people born between 1945 and 1965, a group of about 800,000 people, with prevalence as high as 3.2% versus 1.6% in the general U.S. population.