Low prevalence of HCV infection with predominance of genotype 4 among HIV patients living in Libreville, Gabon

Abstract

Background: Gabon is an endemic area for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) and the risk of co-infection is high.

Method: Between November 2015 and April 2016, we conducted retrospective study on HCV infection among people living with HIV/AIDS (PLHA). A total of 491 PLHA were included in this study and tested for the presence of HCV infection. HIV viral loads were obtained using the Generic HIV viral Load® assay and the CD4+ T cells count was performed using BD FACSCount™ CD4 reagents. HCV screening was performed using the MP Diagnostics HCV ELISA 4.0 kit. HCV genotypes were determined by sequence analysis of NS5B and Core regions. The Mann-Whitney test was used to compare the groups. Chi-2 test and Fisher's Exact Test were used to compare prevalence.

Results: HCV seroprevalence was 2.9% (14/491), (95% confidence interval (CI):1.4-4.3%). The percentage of HCV viremic patients, defined by the detection of HCV RNA in plasma, was 57% (8/14), representing 1.6% of the total population. HCV seroprevalence and replicative infection were not statistically differ with gender. The percentage of co-infection increased with age. No correlation with CD4+ T cells count and HIV viral load level was registered in this study. Identified HCV strains were predominantly of genotype 4 (87.5%) including 4k, 4e, 4g, 4p, 4f and 4c subtypes. Only one strain belonged to genotype 2 (subtype 2q). Analysis of the NS5B region did not reveal the presence of resistance-associated substitutions for sofosbuvir.

Conclusion: A systematic screening of hepatitis C is therefore strongly recommended as well as genotyping of HCV strains in order to adapt treatments for the specific case of people living with HIV/AIDS in Central Africa.

Fig 1. Phylogenetic analysis of HCV NS5B sequences.

Neighbor-joining phylogenetic tree constructed with our sequences and reference sequences for HCV genotypes retrieved from the GenBank. The Kimura two-parameter method of estimating genetic distance was used. Numbers next to the nodes of the tree represent bootstrap values (1000 replicates). Branches for genotype 4 are indicated in red and in green for genotype 2. Our sequences are preceded by a spot. The Gen-Bank accession numbers of the new NS5b sequences of HCV are KY661744 to KY661751.

Fig 2. Phylogenetic analysis of HCV Core sequences.

Neighbor-joining phylogenetic tree constructed with our sequences and reference sequences for HCV genotypes retrieved from the Gen-Bank. The Kimura two-parameter method of estimating genetic distance was used. Numbers next to the nodes of the tree represent bootstrap values (1000 replicates). Branches for genotype 4 are indicated in red and in green for genotype 2. Our sequences are preceded by a spot. The Gen-Bank accession numbers of the new core sequences of HCV are KY661736 to KY661743.