Journal Article

Unravelling the history of hepatitis B virus genotypes A and D infection using a full-genome phylogenetic and phylogeographic approach

Stefanou, Garyfallia, Paraskevis, Dimitrios, Kostaki, Evangelia-Georgia, Hatzakis, Angelos, Kramvis, Anna, Karamitros, Timokratis, Angelis, Konstantinos, Mamais, Ioannis

2018

Overview

Hepatitis B virus (HBV) infection constitutes a global public health problem. In order to establish how HBV was disseminated across different geographic regions, we estimated the levels of regional clustering for genotypes D and A. We used 916 HBV-D and 493 HBV-A full-length sequences to reconstruct their global phylogeny. Phylogeographic analysis was conducted by the reconstruction of ancestral states using the criterion of parsimony. The putative origin of genotype D was in North Africa/Middle East. HBV-D sequences form low levels of regional clustering for the Middle East and Southern Europe. In contrast, HBV-A sequences form two major clusters, the first including sequences mostly from sub-Saharan Africa, and the second including sequences mostly from Western and Central Europe. Conclusion: We observed considerable differences in the global dissemination patterns of HBV-D and HBV-A and different levels of monophyletic clustering in relation to the regions of prevalence of each genotype. The Hepatitis B virus (HBV) is a major cause of liver disease, and according to the World Health Organization, around 257 million people live with Hepatitis B infection. The virus is a relatively ancient one in human history and has been infecting humans for at least 28,000 years. Previous studies have isolated HBV DNA from human skeletons dating from 800 to 7,000 years ago in Europe and Central Asia. Multiple types of this virus exist. Two types called HBV-A and HBV-D are present worldwide, with HBV-A being prevalent in Africa and in Europe, and HBV-D being very common in the Middle East and also in Europe. Even though HBV has been infecting humans for millennia, there is little detailed knowledge of the how the disease spread among populations and geographical areas in the past. Due to few studies in this discipline, understanding of how the different types of HBV were dispersed and disseminated over time has remained patchy. Now, Kostaki et al. analysed HBV-A and HBV-D DNA sequence data from present-day Hepatitis B patients to piece together a global map of historic spread of the virus. The results showed that HBV-D originated in North Africa and the Middle East, while HBV-A originated close to Africa and Europe and probably in the Middle East and Central Asia. HBV-A initially spread in Central Africa, after which it split into two separate pathways. The first spread to Sub-Saharan/eastern and southern Africa, with the other stretching to Sub-Saharan/eastern Africa. Much later, major regional transmissions happened from Africa to Brazil, Haiti and the Indian subcontinent, which are thought to be most likely due to the slave trade. Uncovering the history of the spread of HBV and the human activities associated with it can help to inform public health strategies for avoiding similar situations happening again. These findings could be specifically useful in prevention of HBV in geographical areas where transmission is a high risk, ultimately helping to take steps toward eliminating HBV.

• Publisher: eLife Sciences Publications Ltd,eLife Sciences Publications, Ltd
• Subject: Africa South of the Sahara / Classification / DNA, Viral - genetics / Epidemiology / Europe / Genome, Viral - genetics / Genomes / Genotype / Genotype & phenotype / Genotypes / global dispersal / Hepatitis / Hepatitis B / Hepatitis B - epidemiology / Hepatitis B - genetics / Hepatitis B - virology / hepatitis B virus / Hepatitis B virus - genetics / Hepatitis B virus - pathogenicity / Humans / Infections / Microbiology and Infectious Disease / Molecular Epidemiology / Phylogenetics / Phylogeny / Phylogeography / Public health / Sequence Analysis, DNA