Hepatitis B virus genotype E variability in Africa

Background: In sub-Saharan Africa, genotype 17 is the predominant genotype throughout a vast region spanning from Senegal to Namibia and extending to the Central African Republic in the East. Despite its wide geographic distribution and the high prevalence throughout this genotype E crescent, this genotype has a very low genetic diversity. Objectives: Here we review Our Current understanding of genotype E reanalysing all Currently available sequences of the S gene and the complete genome. Results: Phylogenetic analysis of the complete genome sequences confirmed a previously Suggested South-West/Central African cluster and several lineages of West African sequences. The overall mean genetic distance was 1.71%, with the more Southern countries of the genotype E crescent exhibiting lower distances than the Northern Countries. Conclusions: Genotype E seems to have a longer natural history in the Northern part of the genotype E Crescent than in the Southern Countries. As genotype E is essentially absent from the Americas despite the Afro-American slave trade until at least the beginning of the 19th century, genotype E strains may have been introduced into the general African population only within the past 200 years. How the virus may have spread throughout the genotype E crescent warrants further investigation. (c) 2008 Elsevier B.V. All rights reserved.