Hepatitis Delta Virus – Introduction
Hepatitis delta is the severest form of viral hepatitis and it has the highest fatality rate of all the hepatitis infections, at 20%. The word hepatitis refers to an inflammation of the liver which compromises its functions.
Hepatitis delta is caused by the hepatitis D virus (HDV) which requires the simultaneous presence of the hepatitis B virus (HBV) to propagate. The two viruses act in concert, leading to greater complications than those caused by HBV alone. The immune system attempts to combat the infections by mobilising inflammatory cells that eventually cause cell damage and death. This strategy does not always lead to a clearance of the virus. Thus, repeated cycles of inflammation and resolution (healing) are required which lead to scarring (cirrhosis) and a loss of liver function. Eventually, the infection, coupled with the immune response may also lead to the development of liver cancer. HDV replication in the liver leads to rapid cirrhosis at annual rates of 4% and liver cancer at annual rates of 2.8%.
HDV infection was endemic in the 1970s throughout Southern Europe and caused worse outcomes in patients with positive hepatitis B surface antigen (HBsAg), i.e. those suffering from hepatitis B. Improving standards of health care and the implementation of hepatitis B vaccination programs resulted in a global decline in HDV occurrence. However, hepatitis delta is still a major health concern in the developing world, and with increased immigration to the developed nations, hepatitis delta is poised to make a comeback. The resurgence concern is especially pertinent in light of the fact that there is a lack of effective antiviral drugs to combat this severe disease.
Author: Minaam Abbas