Questions and Answers
What is the primary means of transmission for Hepatitis D virus (HDV)?
Which of the following accurately describes the genetic composition of the Hepatitis D virus (HDV)?
HDV requires which of the following for its replication cycle?
Which receptor is shared by both Hepatitis B virus (HBV) and Hepatitis D virus (HDV) for entry into hepatocytes?
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What percentage of patients typically develop chronic hepatitis after HDV infection?
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The pattern of HDV and HBV infections influences which of the following outcomes?
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Which pattern of HDV infection occurs during the simultaneous infection with HBV and HDV?
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What is a characteristic of individuals infected with HDV regarding HBV replication?
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Which of the following populations is considered high-risk for HDV infection?
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The acute liver failure risk is higher in patients co-infected with which two viruses?
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What percentage of patients with HDV superinfection generally progresses to chronic hepatitis D?
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Which laboratory finding is most indicative of acute HDV infection in a patient already infected with HBV?
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What is the primary endpoint for assessing the effectiveness of Bulevirtide therapy in patients?
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What is a common consequence of chronic HDV infection compared to chronic HBV infection?
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What is the main mechanism of action for Bulevirtide in treating HBV/HDV infections?
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In a patient with suspected HDV superinfection, which serological markers would most likely be absent?
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Which of the following statements is TRUE about the sustained virology response rate for PEG-IFN alpha?
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Which treatment option is available for patients suffering from chronic hepatitis D?
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After the clinical onset of hepatitis D, when does anti-HDV IgM typically disappear?
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Lonafarnib's role in HDV treatment primarily involves which type of mechanism?
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Which of the following is true about the relationship between HDV and HBV infection?
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Which of the following is associated with the administration of Lonafarnib therapy?
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What is the recommended dosage of Bulevirtide for patients receiving treatment?
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What is a primary goal of education for HBV carriers to prevent HDV superinfection?
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What is the primary concern associated with chronic hepatitis D patients who progress to cirrhosis?
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What characterizes the diagnosis of HDV/HBV co-infection?
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What condition may result from acute hepatitis D infection superimposed on chronic HBV infection?
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Which side effect is NOT commonly associated with Bulevirtide treatment?
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What percentage of patients experience relapse after treatment with PEG-IFN alpha for chronic hepatitis D?
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Study Notes
Hepatitis D Virus (HDV) Overview
- HDV is a defective RNA virus requiring Hepatitis B Virus (HBV) for replication.
- Diameter of HDV is 35–37 nm; it has a unique circular RNA genome enveloped by HBsAg.
- Single structural protein encoded by HDV genome: Hepatitis D Antigen (HDAg).
- HDV and HBV utilize the same NTCP receptor to enter human hepatocytes.
- Lacks its own RNA polymerase, relying on host RNA polymerase II for transcription.
Transmission and Infections
- HDV infection occurs only in persons already infected with HBV.
- Transmission mainly through parenteral routes (blood exposure); infrequent sexually and rare vertically.
- High-risk groups: healthcare workers, transfusion recipients, intravenous drug users.
- Two infection patterns:
- Co-infection: simultaneous infection with HBV and HDV.
- Superinfection: HDV infects a chronically HBV-infected patient.
Clinical Presentations
- Co-infection often results in acute hepatitis resembling classic hepatitis B, usually self-limiting.
- Most patients clear both viruses; HDV cannot survive without HBs antigen.
- Severe acute hepatitis may occur, with a risk of acute liver failure in some cases.
- Chronic hepatitis develops in less than 5% of co-infection patients.
- Superinfection typically leads to severe acute hepatitis in 80-90% and often results in chronic hepatitis D.
- Increased morbidity and complications (cirrhosis, HCC) associated with chronic HDV infections.
Diagnosis
- Serological testing for HDV is essential in HBV infected patients.
- First-line screening: detection of anti-HDV antibodies (IgM and IgG).
- Anti-HDV IgM appears 1–2 weeks post-infection, can last up to 12 weeks; anti-HDV IgG emerges as IgM declines.
- Detection of HDV RNA in serum is the most sensitive method for early diagnosis.
- HDAg can be transiently detected in serum but is impractical for routine testing.
Co-infection and Superinfection Diagnostics
- Co-infection diagnosed by the presence of HBV and HDV serological markers.
- Specificity of acute HDV infection marked by finding HDAg, anti-HDV IgM, HDV RNA alongside HBV markers.
- Superinfection indicated by the presence of HBsAg but absence of anti-HBc IgM, with early HDAg and HDV RNA.
Prevention Strategies
- No vaccine specifically for HDV; vaccination against HBV can prevent HDV infections.
- Education for HBV carriers to avoid HDV risks through drug use, sexual, and household transmission.
Treatment of Hepatitis D
- Most cases of acute hepatitis D improve with supportive care; liver transplantation may be needed for fulminant cases.
- NUCs may help with HBV DNA positivity, but they do not treat HDV.
- Bulevirtide available for treatment, inhibits HBV/HDV entry by targeting NTCP receptor.
Chronic Hepatitis D Treatment Options
- Limited treatment options; NUCs typically ineffective.
- PEG-IFN alpha: effective for chronic hepatitis D, but sustained response rates are low (25%).
- Liver transplantation is the only option for progressive cirrhosis cases.
Novel Therapies: Bulevirtide and Lonafarnib
- Bulevirtide: a compound mimicking pre-S1 HBsAg, effective in reducing HDV viremia and normalizing ALT levels; well tolerated.
- Lonafarnib: inhibits farnesyltransferase, essential for HDV replication; promising all-oral therapy options, especially when combined with PEG-IFNα.
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Description
Explore the unique characteristics of the Hepatitis D virus (HDV), a defective RNA virus requiring HBV for its replication. This quiz covers HDV's structure, genome, and the receptor it shares with HBV for entry into human hepatocytes. Test your knowledge of virology and the intricacies of these viruses.
