DELTA-HEPATITIS - THE DISEASE AND THE VIRUS

Delta hepatitis virus is a new human pathogen always found associated with hepatitis B virus (HBV) causing both fulminsnt hepatitis and the accelerated progression of preexisting HBV hepatitis. The virus is coated in HBsAg and contains circular single stranded RNA genome with ery high intramolecular base-pairing, similar to the genomes of plaint viroids, and the HDV antigen, a specific marker of HDV infection also found in the nuclei of infected hepatocytes. The genome is about 1700 nucletides long and of minus polarity with a major constant antigenomic Open Reading Frame (ORF) which codes for the antigen. Replication of viral RNA appears to proceed by a rolling circle mechanism and specific self-cleavage and self-ligation of both genomic and antigenomic HDV RNA strands has been demonstrated in vitro. HDV appears to require HBsAg for its propagation and hepatotropism but not to depend on HBV for replication. © 1990 The British Council 1990.