Chronic hepatitis B and D
Summary
Hepatitis B virus (HBV) is a DNA-containing virus but it relies on reverse transcription of an RNA intermediate for replication. The HBV transcriptional template exists in the nucleus of the infected hepatocyte as a population of covalently closed circular DNA molecules organized into a viral minichromosome. Accurate assessment of liver inflammation and fibrosis is important in guiding decisions on when to initiate treatment. The outcome of chronic HBV infection is variable and affected by patient, virus, and environmental factors. Hepatitis D virus (HDV) is a defective virus which depends on hepatitis B surface antigen for packaging and secretion; thus, chronic HDV infection occurs only in persons with chronic HBV infection. There are two types of HDV infection: simultaneous HBV and HDV coinfection, which rarely results in chronic HDV infection, and HDV superinfection in the setting of chronic HBV infection which almost invariably results in chronic HDV infection.