Genetic and phylogenic characterization of hepatitis B virus in the eastern part of the Democratic Republic of Congo.

Hepatitis B virus (HBV) genotypes show a distinctive geographical distribution worldwide and genotypes A, D, and E are the most frequently found in Africa. There are only limited studies on HBV genotype distribution in Democratic Republic of Congo (DRC), all done in the western part showing a vast majority of genotype E. In our study, HBV strains from South Kivu, an eastern province of the DRC, were analyzed. Sequencing of 41 serum samples from HBV infected patients revealed strains of genotype A in 40/41 (97.6%) and genotype E in 1/41 (2.4%). The phylogenetic analysis showed that nearly all genotypes A (38/40) were closely related to A1 subgenotype strains found in Rwanda, Haiti, and Martinique while only two strains attached to the A2 subgenotype cluster were isolated. The remaining genotype E case was linked to the western African E crescent. Only the I169T nucleotide substitution was observed in two genotype A samples. In conclusion, the genotype A seems to be the most predominant genotype in eastern DRC with the majority belonging to the Afro-Asian subgenotype (A1). This contrasts with the western part of DRC where genotype E is predominant. These results support the hypothesis of an East-West genotypic demarcation.