Hepatitis C virus genotype 4 is highly prevalent in central Africa (Gabon)

Following a survey of hepatitis C virus (HCV) infection recently carried in central Africa (Gabon), we cloned and sequenced PCR products of the 5' non-coding and capsid-encoding regions of HCV RNA from three randomly selected HCV RNA-positive Gabonese subjects. In the capsid-encoding region, the identity between the three Gabonese isolates was 91 to 98%. The three Gabonese sequences showed a divergence of 11 to 17% from published HCV genotypes I to IV (1a, 1b, 2a and 2b) isolates and of 6 to 11% from HCV genotype 4 isolates. Thus the Gabonese isolates, termed HC-G, belong to HCV genotype 4. Based on the sequences of the three isolates, a specific probe (cpsG) was designed to detect the HC-G genotype in 30 randomly selected anti-HCV-positive Gabonese subjects, 14 of whom were HCV RNA-positive. Analysis with cpsG showed that 10 of 14 of the HCV RNA-positive subjects were infected by the HC-G genotype. HC-G is therefore highly prevalent in the HCV RNA-positive Gabonese population. The availability of these Gabonese sequences should facilitate the design of specific serological tests for African HCV isolates.