The Global Hepatitis B Virus Genotype Distribution Approximated from Available Genotyping Data

Abstract

Hepatitis B virus (HBV) is divided into nine genotypes, A to I. Currently, it remains unclear how the individual genotypes contribute to the estimated 250 million chronic HBV infections. We performed a literature search on HBV genotyping data throughout the world. Over 900 publications were assessed and data were extracted from 213 records covering 125 countries. Using previously published HBV prevalence, and population data, we approximated the number of infections with each HBV genotype per country and the genotype distribution among global chronic HBV infections. We estimated that 96% of chronic HBV infections worldwide are caused by five of the nine genotypes: genotype C is most common (26%), followed by genotype D (22%), E (18%), A (17%) and B (14%). Genotypes F to I together cause less than 2% of global chronic HBV infections. Our work provides an up-to-date analysis of global HBV genotyping data and an initial approach to estimate how genotypes contribute to the global burden of chronic HBV infection. Results highlight the need to provide HBV cell culture and animal models that cover at least genotypes A to E and represent the vast majority of global HBV infections to test novel treatment strategies.

High prevalence and genetic diversity of hepatitis B viruses in insectivorous bats from China

“…These results suggesting that HBV originated in bats a long time ago, possibly during the early phases of bat evolution, and the different species of bat HBVs have since co-evolved with their host species. Combined with previous studies (Drexler et al, 2013;He et al, 2013He et al, , 2015Nie et al, 2018;Van Nguyen et al, 2018;Velkov et al, 2018;Wang et al, 2017;Yang et al, 2018), these data indicate that bats should be an important natural reservoir of orthohepadnaviruses.…”

“…HBV classification is based on partial viral S gene or whole genome sequences. When whole genomes are used, the established nucleotide divergence must be of at least 7.5% for defining a genotype, while a classification exclusively based on the S gene requires at least a 4% divergence (Bonvicino et al, 2014;Littlejohn et al, 2016;Velkov et al, 2018). Because full-length nucleotide sequence was not successfully determined in this study, a partial nucleotide sequence of the S gene was used for phylogeny.…”

In Silico Analysis of Genetic Diversity of Human Hepatitis B Virus in Southeast Asia, Australia and New Zealand

“…Due to its high sequence heterogeneity, HBV has 10 recognised genotypes (A to I, and a provisional genotype J) with at least 8% nucleotide divergence, and over 35 subgenotypes with at least 4-8% nucleotide divergence over the whole genome [13,14]. Viral strains typically exhibit geographical and ethnic distributions [13,15]. Generally, genotypes A and D are highly prevalent in Europe, North Africa, North America and Asia, whilst in East and Southeast Asia, Australia and New Zealand genotypes B and C are more commonly found [15].…”

“…Viral strains typically exhibit geographical and ethnic distributions [13,15]. Generally, genotypes A and D are highly prevalent in Europe, North Africa, North America and Asia, whilst in East and Southeast Asia, Australia and New Zealand genotypes B and C are more commonly found [15]. Genotypes E and A predominate in Sub-Saharan Africa, whilst genotypes F, G and H are recorded in Latin America [15].…”

“…A study in 2004 [13] identified only HBV genotypes B and C in the region, except for Australia, in which genotypes D and C were found. Meanwhile, a recent systematic literature review [15] reported genotypes B, C, D and A circulating in these countries. This study therefore aimed to robustly update the situation of HBV types in this region.…”