Background Hepatitis B virus (HBV) places a substantial health burden on Africa. Here, we investigated genetic diversity of HBV variants circulating in 4 countries of sub-Saharan Africa using archived samples. In total, 1492 plasma samples were tested from HIV-infected individuals and pregnant women, among which 143 (9.6%) were PCR-positive for HBV DNA (Côte d’Ivoire, 70/608 [11.5%]; Ghana, 13/444 [2.9%]; Cameroon, 33/303 [10.9%]; and Uganda, 27/137 [19.7%]). Study design/results Phylogenetic analysis of the S-gene sequences identified HBV genotypes E (HBV/E, n = 96) and A (HBV/A, n = 47) distributed as follows: 87% of HBV/E and 13% of HBV/A in Côte d’Ivoire; 100% of HBV/E in Ghana; 67% of HBV/E and 33% of HBV/A in Cameroon; and 100% of HBV/A in Uganda. The average and maximal nucleotide distances among HBV/E sequences were 1.9% and 6.4%, respectively, suggesting a greater genetic diversity for this genotype than previously reported (p < 0.001). HBV/A strains were classified into subgenotypes HBV/A1, HBV/A2 and HBV/A3. In Uganda, 93% of HBV/A strains belonged to HBV/A1 whereas HBV/A3 was the only subgenotype of HBV/A found in Cameroon. In Côte d’Ivoire, HBV/A strains were classified as HBV/A1 (11.1%), HBV/A2 (33.3%) and HBV/A3 (55.6%). Phylogeographic analysis of the sequences available from Africa supported earlier suggestions on the origin of HBV/A1, HBV/A2 and HBV/A3 in East, South and West/Central Africa, respectively. Using predicted amino acid sequences, hepatitis B surface antigen (HBsAg) was classified into serotype ayw4 in 93% of HBV/E strains and adw2 in 68% of HBV/A strains. Also, 7.7% of the sequences carried substitutions in HBsAg associated with immune escape. Conclusions The observations of pan-African and global dissemination of HBV/A1 and HBV/A2, and the circulation of HBV/E and HBV/A3 almost exclusively in West and Central Africa suggest a more recent increase in prevalence in Africa of HBV/E and HBV/A3 compared to HBV/A1 and HBV/A2. The broad genetic heterogeneity of HBsAg detected here may impact the efficacy of prevention and control efforts in sub-Saharan Africa.

Hepatitis C virus (HCV) infection presents an important, but underappreciated public health problem in Africa. In Côte d’Ivoire, very little is known about the molecular dynamics of HCV infection. Plasma samples (n = 608) from pregnant women collected in 1995 from Côte d’Ivoire were analyzed in this study. Only 18 specimens (~3%) were found to be HCV PCR-positive. Phylogenetic analysis of the HCV NS5b sequences showed that the HCV variants belong to genotype 1 (HCV1) (n = 12, 67%) and genotype 2 (HCV2) (n = 6, 33%), with a maximum genetic diversity among HCV variants in each genotype being 20.7% and 24.0%, respectively. Although all HCV2 variants were genetically distant from each other, six HCV1 variants formed two tight sub-clusters belonging to HCV1a and HCV1b. Analysis of molecular variance (AMOVA) showed that the genetic structure of HCV isolates from West Africa with Côte d’Ivoire included were significantly different from Central African strains (P = 0.0001). Examination of intra-host viral populations using next-generation sequencing of the HCV HVR1 showed a significant variation in intra-host genetic diversity among infected individuals, with some strains composed of sub-populations as distant from each other as viral populations from different hosts. Collectively, the results indicate a complex HCV evolution in Côte d’Ivoire, similar to the rest of West Africa, and suggest a unique HCV epidemic history in the country.

The aims of this study are to determine seroprevalence of Hepatitis E virus (HEV) in Tunisian blood donors and to evaluate its risk of parenteral transmission. Sera collected from 426 blood donors were tested for HEV IgG by indirect ELISA. Individuals were recruited from two national transfusion centers, in the North and the South of the country. Seroprevalence of HEV IgG was then compared with two other groups with increased risk of exposure to parenterally transmitted agents: 80 hemophiliac and 286 hemodialysis patients. Among blood donors, the seroprevalence was estimated to be 4.5%. It was significantly higher in the hemophiliac and hemodialysis groups with 7.5% and 10.2%, respectively, (P = 0.002). No significant correlation was observed for this IgG 1 seroprevalence between age and sex among three studied groups. These results suggest that HEV has a high risk of parenteral transmission and confirm that the low endemicity of hepatitis E in Tunisia was observed.