Hepatitis

Hepatitis is inflammation of the liver tissue, a condition that can arise from a variety of causes. The most common triggers are viral infections, specifically those caused by the hepatoviruses A, B, C, D, and E. Other viruses, such as cytomegalovirus, Epstein–Barr virus, and yellow fever virus, can also lead to liver inflammation. Beyond viruses, heavy alcohol consumption, certain medications, toxins, other infections, autoimmune diseases, and non-alcoholic steatohepatitis (NASH) are frequent causes. The modes of transmission differ by virus: hepatitis A and E spread mainly through contaminated food and water; hepatitis B is primarily transmitted sexually, from mother to child during pregnancy or childbirth, or through infected blood; hepatitis C is commonly spread via infected blood, such as through needle sharing; and hepatitis D can only infect individuals already carrying hepatitis B. Symptoms vary widely; some people experience no symptoms, while others develop jaundice (yellowing of the skin and eyes), poor appetite, vomiting, tiredness, abdominal pain, and diarrhea. The disease is classified as acute if it resolves within six months and chronic if it persists longer. Acute hepatitis may resolve on its own, progress to chronic hepatitis, or, rarely, lead to acute liver failure. Chronic hepatitis can advance to cirrhosis (liver scarring), liver failure, or liver cancer. Prevention through immunization is available for hepatitis A, B, and D. Treatment options include antiviral medications for chronic hepatitis C, lifestyle changes for NASH, immune-suppressing drugs for autoimmune hepatitis, and liver transplantation for severe liver failure. Globally, hepatitis A affected about 114 million people in 2015, chronic hepatitis B affected roughly 343 million, and chronic hepatitis C about 142 million. In the United States, NASH affects around 11 million people, and alcoholic hepatitis about 5 million. The condition results in over a million deaths each year, mostly from cirrhosis or liver cancer. The word "hepatitis" comes from the Greek *hêpar* (liver) and *-itis* (inflammation).