HDV is an unusual, defective, single-stranded RNA virus. It requires the presence of HBV to replicate. HDV infection develops only in patients who are positive for the hepatitis B surface antigen (HBsAg). Infection may be acquired along with HBV (co-infection) or after HBV infection (superinfection).
An estimated 15-20 million people infected with HBV worldwide are also infected with HDV.
It is an important cause of acute and severe chronic liver damage in some parts of the world (Mediterranean, parts of Eastern Europe, Middle East, Africa, and South America).
Route of transmission
It needs hepadnavirus to function and for its propagation in hepatocytes, and is therefore acquired as a co-infection with HBV, or as a superinfection in those with existing chronic HBV infection. Therefore transmission is, like HBV, by exposure to infected blood and blood products. It can be transmitted percutaneously and sexually. Perinatal transmission is rare.
Hepatitis – Hepatitis D
HDV replicates only in liver cells and so the cellular damage associated with HDV infection involves mainly the liver. Immune-mediated liver damage is thought to be implicated in HDV infection. HDV co-infection with HBV may be associated with increased risk of severe clinical hepatitis, fulminant hepatic failure, chronic liver disease, cirrhosis and hepatocellular carcinoma.
Anti-HDV antibody. Other investigations as indicated for hepatitis, liver failure, cirrhosis and hepatocellular carcinoma.
Current treatments include pegylated interferon alfa and liver transplantation, which can be curative. Management is otherwise supportive.