What is Hepatitis D?

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Hepatitis D – known as "hepatitis delta" - is a liver infection caused by the hepatitis D virus that results in the most severe form of viral hepatitis known to humans. Only those already infected with hepatitis B, however, can acquire hepatitis D, as it is dependent on the hepatitis B virus to reproduce.

Worldwide, more than 240 million people live with hepatitis B and of this number, an estimated 15-20 million are also infected with the hepatitis delta virus (HDV). Hepatitis D infections lead to more serious liver disease than hepatitis B infection alone. It is associated with faster progression to liver fibrosis, increased risk of liver cancer, and early decompensated cirrhosis and liver failure.

Types of Infection

Hepatitis D can be acquired either through co-infection (infection with HDV and hepatitis B at the same time) or super-infection (infection with HDV after a person has already acquired hepatitis B). A co-infection generally resolves spontaneously after about 6 months, but it can sometimes result in a life-threatening or fatal liver failure.

A super-infection is the most common form of hepatitis D and leads to a more severe liver disease than a chronic hepatitis B infection alone. Up to 90% of super-infected individuals will develop chronic hepatitis D, of which approximately 70% will progress to cirrhosis (liver scarring), compared to 15-30% of those infected only with the hepatitis B virus.

Prevention

There is no vaccine for HDV, but it can be prevented by getting the hepatitis B vaccine to help eliminate the risk of infection with the hepatitis B virus. There is a simple and easily accessible blood test for HDV.  It is important that patients with chronic HBV get tested for HDV. Having the HDV test may help save lives by making sure infected persons receive appropriate medical care and treatment. It is important for patients with chronic hepatitis B infection to get tested for HDV. 

About the Virus

Virus

Source: Eiger Biopharmaceuticals

The hepatitis D virus (HDV) is a single-stranded, circular RNA virus that is the smallest virus known to infect humans. It is unusual in that it needs specific help from the hepatitis B virus in order to infect and replicate in liver cells. The HDV’s defective structure requires the envelope proteins of the hepatitis B virus for its own assembly; thus, new hepatitis D virus particles can only be produced in a liver cell that is infected with both viruses.