Possible origins and evolution of the hepatitis B virus (HBV)

Locarnini, Stephen; Littlejohn, Margaret; Aziz, Muhammad Nazri; Yuen, Lilly

doi:10.1016/j.semcancer.2013.08.006

Cited by 83 publications

(70 citation statements)

References 120 publications

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“…It has been shown that the evolution of exogenous hepadnaviruses is characterized by frequent recent host-switching [62,63]. Our rooted tree indicates that snake hepadnaviruses are probably paraphyletic and that bird hepadnaviruses (endogenous þ exogenous) are closer to mammalian than to snake hepadnaviruses, which is incongruent with the host phylogeny (in which birds are closer to snakes than to mammals [64]).…”

Section: Discussionmentioning

confidence: 73%

Endogenous hepadnaviruses, bornaviruses and circoviruses in snakes

et al. 2014

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We report the discovery of endogenous viral elements (EVEs) from Hepadnaviridae, Bornaviridae and Circoviridae in the speckled rattlesnake, Crotalus mitchellii, the first viperid snake for which a draft whole genome sequence assembly is available. Analysis of the draft assembly reveals genome fragments from the three virus families were inserted into the genome of this snake over the past 50 Myr. Cross-species PCR screening of orthologous loci and computational scanning of the python and king cobra genomes reveals that circoviruses integrated most recently (within the last approx. 10 Myr), whereas bornaviruses and hepadnaviruses integrated at least approximately 13 and approximately 50 Ma, respectively. This is, to our knowledge, the first report of circo-, borna-and hepadnaviruses in snakes and the first characterization of non-retroviral EVEs in non-avian reptiles. Our study provides a window into the historical dynamics of viruses in these host lineages and shows that their evolution involved multiple host-switches between mammals and reptiles.

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Section: Discussionmentioning

confidence: 73%

Endogenous hepadnaviruses, bornaviruses and circoviruses in snakes

et al. 2014

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“…When compared with 1,440 human and nonhuman HBV strains, its sequence diverged by 10.7-15.7% from other genotypes and did not show any evidence of recombination [13]. In a later analysis, using additional gibbon/orangutan HBV sequences for comparison, Locarnini et al [44] concluded that genotype ‘J' is in fact a recombinant of genotype C and gibbon HBV in the S region. Thus, although the high intergroup divergence of genotype ‘J' meets the criterion for classification into a separate genotype, it may represent a cross-species transmission [13], and identification and analysis of additional sequences will be required before the existence of this 10th genotype can be confirmed.…”

Section: ‘Genotype J'mentioning

confidence: 99%

Genotypes and Genetic Variability of Hepatitis B Virus

Kramvis¹

2014

Intervirology

408

367

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Sequence heterogeneity is a feature of hepatitis B virus (HBV), the prototype member of the family Hepadnaviridae. Based on an intergroup divergence of greater than 7.5% across the complete genome, HBV has been classified phylogenetically into 9 genotypes, A-I, with a putative 10th genotype ‘J', isolated from a single individual. With between approximately 4 and 8% intergroup nucleotide divergence across the complete genome and good bootstrap support, genotypes A-D, F, H, and I are classified further into subgenotypes. There is a broad and highly statistically significant correlation between serological subtypes and genotypes, and in some cases, serological subtypes can be used to differentiate subgenotypes. The genotypes, and certain subgenotypes, have distinct geographical distributions and are important in both the clinical manifestation of infection and response to antiviral therapy. HBV genotypes/subgenotypes and genetic variability of HBV are useful in epidemiological and transmission studies, tracing human migrations, and in predicting the risk for the development of severe liver disease and response to antiviral therapy. Moreover, knowledge of the genotype/subgenotype is important in implementing preventative strategies. Thus, it is crucial that new strains are correctly assigned to their respective genotype/subgenotype and consistent, unambiguous, and generally accepted nomenclature is utilized.

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“…For example, previous large cohort studies in Taiwan showed that the prevalence of mixed HBV genotype infections was 16.3% and 34.4%, respectively, in HBsAg-positive and occult HBV-infected intravenous drug users (Chen et al 2004a;Lin et al 2007a). Coinfection with different HBV genotypes further leads to recombination of different viral strains (Locarnini et al 2013). Intergenotypic recombination of HBV strains has been widely reported.…”

Section: Intergenotypic Recombinationmentioning

confidence: 99%

Hepatitis B Virus Genotypes and Variants

Lin

Kao

2015

Cold Spring Harbor Perspectives in Medicine

210

139

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At least 10 hepatitis B virus (HBV) genotypes (A to J) with distinct geographic distributions and several HBV mutants, including precore/core promoter mutations and pre-S/S deletion mutations, have been recognized to be not only predictive of liver disease progression but also associated with response to antiviral therapy. HBV genotype -specific pathogenesis may contribute to heterogeneous clinical outcomes in chronic hepatitis B patients across the world. For example, patients with HBV genotypes C and D infection have a lower rate of spontaneous HBeAg seroconversion. In addition, HBV genotypes C and D have a higher frequency of core promoter and pre-S mutations than genotypes A and B. Genotypes C and D also carry a higher lifetime risk of cirrhosis and HCC development than genotypes A and B. Core promoter and pre-S mutations also correlate with an increased risk of hepatocellular carcinoma (HCC). Therapeutically, genotypes A and B patients have a better response to interferon-based therapy than genotypes C and D patients, but the response to nucleos(t)ide analogs is comparable across different HBV genotypes. In conclusion, HBV genotypes and variants may serve as viral genetic markers to predict disease progression as well as help practicing physicians optimize individualized antiviral therapy in clinical practice.

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Possible origins and evolution of the hepatitis B virus (HBV)

Cited by 83 publications

References 120 publications

Endogenous hepadnaviruses, bornaviruses and circoviruses in snakes

Endogenous hepadnaviruses, bornaviruses and circoviruses in snakes

Genotypes and Genetic Variability of Hepatitis B Virus

Hepatitis B Virus Genotypes and Variants

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