Hepatitis Delta Virus

• Hepatitis Delta Virus is a “defective” virus, meaning it requires the presence of Hepatitis B Virus (HBV) to replicate and cause infection.
• HDV infection can manifest as co-infection (simultaneous with HBV) or superinfection (HDV infecting someone already chronically infected with HBV), with superinfection often leading to more severe outcomes.
• Symptoms range from mild to severe, including fatigue, jaundice, and abdominal pain, often worsening the course of HBV-related liver disease.
• Transmission pathways are similar to HBV, primarily through contact with infected blood or bodily fluids.
• Treatment options are limited and challenging, primarily involving interferon-alpha, with ongoing research into new antiviral therapies.

What is Hepatitis Delta Virus?

To understand what is Hepatitis Delta Virus, it’s crucial to recognize its unique characteristic: it is a subviral agent, often referred to as a “defective” RNA virus. This means HDV cannot replicate on its own; it absolutely requires the Hepatitis B Virus (HBV) to provide the necessary surface antigen (HBsAg) for its assembly and spread. Consequently, HDV infection only occurs in individuals who are already infected with HBV, making it the most severe form of viral hepatitis.

Globally, HDV affects an estimated 12 million people, predominantly in regions where HBV is endemic, such as parts of Eastern Europe, the Mediterranean basin, and Central and West Africa. According to the World Health Organization (WHO), HDV infection is associated with more rapid progression to cirrhosis, liver failure, and hepatocellular carcinoma (liver cancer) compared to chronic HBV infection alone, significantly increasing morbidity and mortality rates.

Symptoms and Transmission

The presentation of hepatitis delta virus symptoms can vary significantly depending on whether it occurs as a co-infection or a superinfection. In co-infection, where HBV and HDV are acquired simultaneously, symptoms can range from mild to severe acute hepatitis, often indistinguishable from acute HBV. However, superinfection, where HDV infects an individual already living with chronic HBV, typically leads to a more severe acute hepatitis, often resulting in rapid progression to chronic HDV infection and accelerated liver damage.

Common symptoms, when present, can include:

• Severe fatigue
• Jaundice (yellowing of the skin and eyes)
• Dark urine
• Pale stools
• Abdominal pain, particularly in the upper right quadrant
• Nausea and vomiting
• Loss of appetite

Regarding hepatitis delta virus transmission, the routes are largely identical to those of Hepatitis B Virus. This primarily involves contact with infected blood or other bodily fluids. Key transmission pathways include sharing contaminated needles among people who inject drugs, unprotected sexual contact with an infected person, and from an infected mother to her child during birth. Less commonly, transmission can occur through contaminated medical or dental equipment or through blood transfusions in regions where screening is inadequate.

Treatment for Hepatitis Delta Virus

Currently, hepatitis delta virus treatment options are limited and present significant challenges. The primary therapeutic approach involves the use of pegylated interferon-alpha, which aims to suppress viral replication and reduce liver inflammation. However, the response rates to this treatment are often modest, and it can be associated with considerable side effects, requiring careful monitoring by healthcare professionals.

Given the complexity of HDV, which relies on HBV for its replication, managing the underlying Hepatitis B infection is also crucial. While there is no specific cure for HDV, ongoing research is exploring new antiviral agents and therapeutic strategies, including direct-acting antivirals, to improve outcomes for those affected. Vaccination against Hepatitis B is the most effective way to prevent HDV infection, as it prevents the necessary co-factor for HDV to establish itself.