Hepatitis D Virus (HDV)

Categorization
Genome: RNA Virus
Transmission
  • Parenteral Transmission
  • Sexually Transmitted Disease
  • Mother-to-Child Transmission
Viral Components
  • Hepatitis D Virus is solely composed of a nucleocapsid and uses the envelope of Hepatitis B Virus (HBV) to spread from cell to cell. Consequently, HDV can only replicate if a patient is simultaneously infected with HBV.
Sequences of Infection
  • Co-infection: HBV and HDV may be transmitted simultaneously during a single infective event. Superinfection: HDV may be transmitted to a patient already chronically infected with HBV.
Serology
  • The immune system elaborates Anti-HDV IgM following infection which in many cases switches to Anti-HDV IgG later on. However, in many cases Anti-HDV IgM does not switch to IgG; therefore, the sole presence of IgM cannot distinguish between acute or chronic infection with HDV.
Clinical Consequences
  • Co-infection:
  • Superinfection:
    • Superinfection of HDV on a background of chronic HBV infection may appear as a flareup in chronic viral hepatitis or resemble a syndrome akin to acute viral hepatitis. However, in most cases HDV infection also enters a chronic course but increases the risk of developing cirrhosis above that of single infection with HBV.