Mapping hepatitis B virus genotypes on the African continent from 1997 to 2021: a systematic review with meta-analysis

Abstract

Hepatitis B virus (HBV) has ten genotypes (A–J) and over 40 sub-genotypes based on the divergence of ≥ 8% and 4 to < 8% in the complete genome respectively. These genotypes and sub-genotypes influence the disease prognosis, response to therapy and route of viral transmission. Besides, infection with mixed genotypes and recombinant genotypes has also been reported. This study aimed at mapping the de novo genotypes and correlate them with the immigration trends in order to inform future research on the underlying reasons for the relative distribution of HBV genotypes from a large sample size pooled from many primary studies. Data was extracted from 59 full research articles obtained from Scopus, PubMed, EMBASE, Willy library, African Journal Online (AJOL) and Google Scholar. Studies that investigated the genotypes, sub-genotypes, mixed genotypes and recombinant were included. The Z-test and regression were used for the analysis. The study protocol is registered with PROSPERO under the registration number CRD42022300220. Overall, genotype E had the highest pooled prevalence significantly higher than all the other genotypes (P < 0.001). By region, genotype A posted the highest pooled prevalence in eastern and southern Africa, E in west Africa and D in north Africa (P < 0.0001). Regarding the emerging genotypes B and C on the African continent, genotype B was significantly higher in south Africa than C (P < 0.001). In contrast, genotype C was significantly higher in east Africa than west Africa (P < 0.0001). The A1 and D/E were the most diverse sub-genotypes and genotype mixtures respectively. Finally, we observed a general progressive decrease in the prevalence of predominant genotypes but a progressive increase in the less dominant by region. Historical and recent continental and intercontinental migrations can provide a plausible explanation for the HBV genotype distribution pattern on the African continent.

An Oxford Nanopore Technology-Based Hepatitis B Virus Sequencing Protocol Suitable For Genomic Surveillance Within Clinical Diagnostic Settings

“…Nevertheless, the fact that HBV recombinants have been so widely and increasingly detected suggests that the recombinants detected here are likely accurate. Genotype B/E recombinants identified in Eritria are the most common in Africa [35]. Genotype D/E recombinants are also common, having been identified in eight countries, namely Kenya, Niger, Egypt, Ghana, Libya, Mali, Eritria, and Uganda [35], followed by genotype A/E, identified in five countries, namely Uganda, Eretria, Ghana, Niger, and Mozambique [35, 36], and genotype A/D, reported in Egypt, Eretria, and Uganda [35].…”

Hepatitis B virus genotype surveillance in Canadian blood donors and a referred patient population, 2016–2021

“…These genotypes have distinct geographic distribution [19], as do their sub-genotypes, characterized by >3%-4% genomic nucleotide divergence [6,20]. Accordingly, infection with different HBV genotypes and their related clinical outcomes are often highly associated with different ethnic populations [21][22][23].…”

Host and HBV Interactions and Their Potential Impact on Clinical Outcomes

“…( 10) Some viral particles are transported back into the nucleus to increase the pool of cccDNA. (11,12) Within the RER, the viral particles are enveloped by a lipid membrane, which carries hepatitis B surface antigen (HBsAg). ( 13) Finally, the mature virions are released into the bloodstream, accompanied by empty particles that serve as decoys for the immune response.…”

“…(11) Immune cells produce cytokines that initiate apoptosis through cytoplasmic and nuclear pathways. (12) The nuclear pathway starts with perforin release, forming channels in the cell membrane for granzymes to enter the cytoplasm. Granzymes affect mitochondria, generating reactive oxygen species (ROS).…”

“…(4) CD8 lymphocytes (CD8 T cells) can be activated by the major histocompatibility complex class I (MHC-I), specifically human leukocyte antigen-A2 (HLA-A2) subtype, presenting the peptides produced by the proteasome (11). Immune cells produce cytokines that initiate apoptosis through cytoplasmic and nuclear pathways (12). The nuclear pathway starts with perforin release, forming channels in the cell membrane for granzymes to enter the cytoplasm.…”