HEPATITIS-C VIRUS GENOTYPE-4 IS HIGHLY PREVALENT IN CENTRAL-AFRICA (GABON)

Following a survey of hepatitis C virus (HCV) infection recently carri ed in central Africa (Gabon), we cloned and sequenced PCR products of the 5' non-coding and capsid-encoding regions of HCV RNA from three ra ndomly selected HCV RNA-positive Gabonese subjects. In the capsid-enco ding region, the identity between the three Gabonese isolates was 91 t o 98%. The three Gabonese sequences showed a divergence of 11 to 17% f rom published HCV genotypes I to IV (1a, 1b, 2a and 2b) isolates and o f 6 to 11% from HCV genotype 4 isolates. Thus the Gabonese isolates, t ermed HC-G, belong to HCV genotype 4. Based on the sequences of the th ree 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 genotyp e. HC-G is therefore highly prevalent in the HCV RNA-positive Gabonese population. The availability of these Gabonese sequences should facil itate the design of specific serological tests for African HCV isolate s.