Hepatitis D Virus (HDV) is a liver infection that can lead to severe health complications. This virus can only infect individuals already infected with the Hepatitis B virus (HBV). HDV infection is a global health concern, impacting populations already living with HBV due to its potential for aggressive liver disease.
Understanding Hepatitis D Virus
Hepatitis D Virus is a small, circular RNA virus that cannot replicate on its own. It is considered a defective virus because it requires the presence of the Hepatitis B surface antigen (HBsAg) for its assembly and spread within the human body. This means HDV infection only occurs in individuals already positive for HBV.
There are two main patterns of HDV infection: co-infection and superinfection. Co-infection happens when a person acquires both HBV and HDV simultaneously. This acute form often resolves spontaneously, with a low chance of becoming chronic. Superinfection occurs when HDV infects someone already living with chronic HBV. This scenario leads to a more severe and rapidly progressing liver disease, with a high likelihood of developing chronic HDV infection.
How Hepatitis D Virus Spreads
The transmission routes for Hepatitis D Virus are similar to those of Hepatitis B Virus, primarily involving contact with infected blood or other body fluids. This can occur through sharing needles or syringes, which is a common risk factor among people who inject drugs. Unprotected sexual contact with an infected individual also poses a risk for transmission.
Perinatal transmission, from mother to child during birth, is rare. Casual contact, such as hugging, kissing, or sharing food and drinks, does not transmit HDV. Avoiding sharing personal items like razors or toothbrushes, which might have blood on them, also helps prevent spread.
Recognizing Hepatitis D Virus Symptoms
Symptoms of Hepatitis D Virus infection often resemble those of other forms of viral hepatitis. In acute HDV infection, symptoms appear three to seven weeks after exposure. These can include general fatigue, nausea, vomiting, and abdominal discomfort. Distinct signs like dark urine, pale or clay-colored stools, and jaundice, a yellowing of the skin or eyes, may also be present.
Symptoms in chronic HDV infection can be less apparent or even absent. Despite this, the virus continues to cause progressive liver damage, which can lead to severe conditions like cirrhosis and liver failure over time. Some people with chronic HDV may not experience noticeable signs for many years.
Diagnosis and Management
Diagnosing Hepatitis D Virus infection involves specific blood tests. Healthcare providers look for antibodies against HDV or directly detect HDV RNA in the blood. Since HDV requires HBV, concurrent testing for Hepatitis B surface antigen (HBsAg) and other HBV markers is always performed to confirm co-infection.
The primary approved treatment for chronic HDV infection has been pegylated interferon-alpha. This medication works by using the body’s immune system to suppress viral replication and reduce liver inflammation. While it can improve liver condition, it does not consistently achieve high rates of viral clearance and can have side effects.
Newer antiviral agents are under development and have shown promise. Bulevirtide, for instance, is an entry inhibitor that prevents the virus from entering liver cells. Other investigational therapies include nucleic acid polymers, prenylation inhibitors, and RNA interference-based treatments. These emerging treatments aim to offer improved efficacy and fewer side effects, with some already approved in certain regions. In severe cases where liver function declines significantly due to HDV-related damage, a liver transplant may become a necessary intervention.
Preventing Hepatitis D Virus
The most effective way to prevent Hepatitis D Virus infection is to prevent Hepatitis B Virus infection. The Hepatitis B vaccine is highly effective in preventing HBV, thus preventing HDV. This vaccine is recommended for all infants at birth, children up to 18 years of age, and adults at higher risk.
Other preventive measures align with those for HBV. These include practicing safe injection habits by avoiding sharing needles or syringes. Engaging in safe sexual practices also reduces the risk of transmission. Screening blood products before transfusions is a standard safety measure that prevents the spread of blood-borne viruses, including HDV. Screening pregnant women for HBV also allows for interventions to prevent mother-to-child transmission, which helps prevent HDV.