ANALYSIS OF A HEPATITIS-DELTA VIRUS ISOLATE FROM THE CENTRAL-AFRICAN-REPUBLIC

Based on the analysis of HDV genomes from different areas of the world , three genotypes of HDV have been identified. Genotype I is the most prevalent and widespread. Genotype II is represented by two isolates f rom Japan and Taiwan. Genotype III has been found only in the Amazonia n basin where it is associated with a history of severe disease, fulmi nant hepatitis with microvesicular steatosis (spongiocytosis). We repo rt here the cloning and the analysis of the complete viral genome from woodchuck serum-derived HDV RNA after transmission from Central Afric an Republic (RCA) patients with fulminant spongiocytic delta hepatitis . Two overlapping cDNA fragments, covering the entire HDV genome, were generated by RT-PCR and cloned. Three clones obtained from each fragm ent were fully sequenced. A complete consensus RCA HDV genome was reco nstituted. The individual and the consensus nucleotide sequences were compared with those of 16 other fully sequenced isolates belonging to the three genotypes. Phylogenetic trees generated by the neighbour joi ning method firmly place our isolate in genotype I, and show that this RCA isolate differs significantly from the east African isolates prev iously analysed. Transfection experiments showed that the isolate is r eplication-competent, but less so than the control ''wild-type'' strai n. Two novel mutations encountered in this work, one in the antigenomi c ribozyme sequence and one affecting delta antigen, were studied.