All hepadnaviruses known so far have a very limited host range, restricted to their natural hosts and a few closely related species. This is thought to be due mainly to sequence divergence in the large envelope protein and species-specific differences in host components essential for virus propagation. Here we report an infection of cranes with a novel hepadnavirus, designated CHBV, that has an unexpectedly broad host range and is only distantly evolutionarily related to avihepadnaviruses of related hosts. Direct DNA sequencing of amplified CHBV DNA as well a sequencing of cloned viral genomes revealed that CHBV is most closely related to, although distinct from, Ross' goose hepatitis B virus (RGHBV) and slightly less closely related to duck hepatitis B virus (DHBV). Phylogenetically, cranes are very distant from geese and ducks and are most closely related to herons and storks. Naturally occurring hepadnaviruses in the last two species are highly divergent in sequence from RGHBV and DHBV and do not infect ducks or do so only marginally. In contrast, CHBV from crane sera and recombinant CHBV produced from LMH cells infected primary duck hepatocytes almost as efficiently as DHBV did. This is the first report of a rather broad host range of an avihepadnavirus. Our data imply either usage of similar or identical entry pathways and receptors by DHBV and CHBV, unusual host and virus adaptation mechanisms, or divergent evolution of the host genomes and cellular components required for virus propagation.Infections caused by hepatitis B virus (HBV) remain one of the most serious medical challenges worldwide, with approximately 350 million humans being chronically infected. There is currently no established effective therapy available. HBVs are small enveloped DNA viruses constituting the family Hepadnaviridae and propagating their genome by reverse transcription of an RNA intermediate (22). As well as in humans, orthohepadnaviruses have been identified so far in rodents such as woodchucks (woodchuck hepatitis virus), ground and arctic squirrels (ground squirrel hepatitis virus and arctic squirrel hepatitis virus), and recently in Old World as well as New World primates including woolly monkeys, orangutans, gorillas, and gibbons (17, 18). Naturally occurring infections by avihepadnaviruses were first described in Pekin ducks (Anas domesticus) (duck hepatitis B virus DHBV) from China and the United States (13, 33) and were subsequently found in various other duck strains (references 21 and 29 and references therein). DHBV-related viruses have also been isolated from four other avian species, namely, grey heron (Ardea cinerea) (he- Extracellularly, virions contain partially double-stranded DNA of exquisitely compact size (3.0 to 3.3 kbp). Following arrival in the nucleus, the incoming viral genome is converted into covalently closed circular DNA and serves as the template for viral transcription. The genes of hepadnaviruses are all extensively overlapping and encode the envelope (pre-S and S), the nucleocapsid (core or C),...
Heron hepatitis B viruses (HHBVs) in three subspecies of free-living great blue herons (Ardea herodias) from Florida, USA, were identified and characterized. Eight of 13 samples were positive in all assays used, whereas sera from egrets, which are also members of the family Ardeidae, were negative in the same assays. Comparative phylogenetic analysis of viral DNA sequences from the preS/S region of previously reported and novel HHBV strains isolated from captive grey herons (Germany) and free-ranging great blue herons (USA), respectively, revealed a strong conservation (95 % sequence similarity) with two separate clusters, implying a common ancestor of all strains. Our data demonstrate for the first time that different subspecies of herons are infected by HHBV and that these infections exist in non-captive birds. Phylogenetic analysis and the fact that the different heron species are geographically isolated populations suggest that lateral transmission, virus adaptation and environmental factors all play a role in HHBV spreading and evolution.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.