Hepatitis D virus (HDV) is a deltavirus that is dependent on hepatitis B virus (HBV) for replication. It can infect individual simultaneously with HBV (co-infection) or superinfect those who are already chronic carriers of HBV.
HDV infection is particularly seen in IV drug users.
Endemic to Africa, South America and Mediterranean Basin
Co-infections with HBV
Clinically indistinguishable from an acute icteric HBV infection, although usually has severe symptoms.
Superinfections in chronic carriers of HBV
Results in an acute flare-up of previously inactive chronic HBV infection. This is usually followed by spontaneous recovery. An increase in ALT may the only indication of infection. Occasionally, there may be simultaneous recovery of HBC and HDV.
Chronic infection with HBV and HDV frequently causes rapid progression to chronic hepatitis and cirrhosis.
Anti-HDV antibodies are the principal investigation. Co-infection produces low titres (usually IgM), while superinfection results in high titres (IgM initially, then IgG).
There is no specific treatment for HDV. Management relies on adequately controlling HBV.