Hepatitis delta virus (HDV) infection and disease.

The conformational and biologic properties of the hepatitis delta virus (HDV), a defective RNA hepatotropic pathogen dependent on obligatory helper functions provided by the hepatitis B virus (HBV), are different from the properties of conventional RNA animal viruses but resemble in many aspects the characteristics of the satellite RNAs and satellite viruses of higher plants. The HBsAg coat provided to HDV by HBV makes the defective virus transmissible via the vectors and modes of transmission of the ubiquitous helper; alike HBV, HDV is prevalent in tropical and subtropical areas and in the Mediterranean basin. In contrast to HBV, HDV is highly pathogenic and its infection aggravates the underlying HBV infection upon which it thrives. The defective pathogen has been recognized worldwide as a major cause of fulminant hepatitis and of severe chronic hepatitides leading to cirrhosis and liver failure. There is yet no established therapy for this ominous disease.