Genetic diversity of hepatitis viruses in West-African countries from 1996 to 2018

Abstract

The severity of hepatic pathology and the response to treatment depend on the hepatitis virus genotype in the infected host. The objective of this review was to determine the distribution of hepatitis virus genotypes in West African countries. A systematic review of the literature in PubMed, Google Scholar and Science Direct was performed to identify 52 relevant articles reporting hepatitis A, B, C, D, E and G viruses genotypes. Hepatitis B virus (HBV) genotype E with a prevalence of 90.6% (95%CI: 0.891-0.920) found in this review, is characterized by low genetic diversity. Hepatitis C virus (HCV) genotypes 1 and 2 represented 96.4% of HCV infections in West African countries, while hepatitis delta virus, hepatitis A virus, hepatitis G virus genotypes 1 and HEV genotype 3 were reported in some studies in Ghana and Nigeria. HBV genotype E is characterized by high prevalence, low genetic diversity and wide geographical distribution. Further studies on the clinical implications of HBV genotype E and HCV genotypes 1 and 2 are needed for the development of an effective treatment against this viral hepatitis in West African countries. Surveillance of the distribution of different genotypes is also needed to reduce recombination rates and prevent the emergence of more virulent viral strains.

Keywords: Genotypes; Hepatitis virus; Mutations; Recombination; West African Economic and Monetary Union.

Figure 1

Flow diagram showing the method for the study selection. The database search for the search strategy described in the section was cleaned up to exclude review articles and duplicates. Titles and abstracts were included in the literature review. Seroprevalence articles, articles with ambiguous data that did not meet the inclusion criteria were then excluded during the full-text review. Fifty-two (52) relevant articles were finally included for this review.

Figure 2

Phylogenetic tree of 53 hepatitis B virus genotype E and A sequences identified in West African Economic and Monetary Union countries including Ghana and Nigeria (indicated ♦). Phylogenetic analysis was performed with the neighbor-joining algorithm based on the Kimura two-parameter distance estimation method. Only bootstrap values of > 80% are shown (1.000 replicates). Reference hepatitis B virus sequences (44) recovered from GenBank are denoted with their accession numbers and genotypes/sub-genotypes are indicated.

Figure 3

Hepatitis B virus genotypes reported in West African Economic and Monetary Union countries, Ghana and Nigeria. Pie charts show the proportion of different hepatitis B virus genotypes in West African countries according to the data in Table 1.

Figure 4

Hepatitis C virus genotypes reported in West African Economic and Monetary Union countries, Ghana and Nigeria. Pie charts show the proportion of different hepatitis B virus genotypes in West African countries according to the data in Table 2.