Dhepatiit

Dhepatiit, or hepatitis D, is a viral liver disease caused by the hepatitis D virus (HDV). HDV is a defective RNA virus that cannot replicate without the hepatitis B surface antigen (HBsAg). Consequently, HDV infects only people who currently have hepatitis B virus (HBV) infection or who are susceptible to HBV infection.

Transmission occurs through exposure to infected blood and bodily fluids. Risk factors include injection drug use, unsafe medical injections, blood transfusions before screening, and unprotected sex. HDV is most prevalent in regions with high HBV prevalence, including parts of Eastern Europe, the Mediterranean, the Middle East, and the Amazon basin; international migration has broadened its distribution. Infection can be acute (coinfection) or occur as superinfection in someone with chronic HBV, with the latter more likely to cause chronic liver disease.

HDV replication occurs in hepatocytes by co-opting host enzymes and requires HBsAg to form infectious virions. The liver injury results from the host immune response and viral activity. Coinfection may be self-limiting, but superinfection on chronic HBV commonly leads to rapid progression to cirrhosis and carries a higher risk of decompensation and hepatocellular carcinoma than HBV alone.

Many cases are asymptomatic; when symptoms occur they include fatigue, jaundice, abdominal pain, and elevated liver enzymes. Diagnosis relies on positive anti-HDV antibodies and/or HDV RNA testing in a patient who is HBsAg positive. Distinguishing acute from chronic infection involves serology and RNA levels.

There is no widely effective cure for HDV. Management focuses on treating HBV and monitoring liver disease. Interferon-based therapy has limited durability. Newer therapies, such as bulevirtime (an entry inhibitor), have shown activity in trials and are approved in some regions. Vaccination against HBV prevents HDV infection; maintaining vaccination and safe practices reduces risk.