Bornaviridae
| Bornaviridae | |
|---|---|
| Virus classification | |
| Group: | Group V ((−)ssRNA)
|
| Order: | |
| Family: | Bornaviridae
|
| Genus: | Bornavirus
|
| Type Species | |
Bornavirus is a genus of viruses in the order Mononegavirales. Horses, sheep, cattle, rodents, birds, and human serve as natural hosts. There are currently five species in this genus, and it is the only genus in its family (Bornaviridae). Diseases associated with this genus include: mammals borna disease : fatal neurologic disease, restricted to central Europe. birds: encephalitis, proventricular dilatation disease.[1][2]
Taxonomy
Group: ssRNA(-)
- Family: Bornaviridae
Structure
Viruses in Bornavirus are enveloped, with spherical geometries. The diameter is around 70 to 130 nm. Genomes are linear, around 8.9kb in length. The genome codes for 9 proteins. [1]
| Genus | Structure | Symmetry | Capsid | Genomic Arrangement | Genomic Segmentation |
|---|---|---|---|---|---|
| Bornavirus | Spherical | Enveloped | Linear | Monopartite |
Life Cycle
Viral replication is nuclear. Entry into the host cell is achieved by attachment of the viral GP glycoproteins to host receptors, which mediates clathrin-mediated endocytosis. Replication follows the negative stranded RNA virus replication model. Negative stranded rna virus transcription, using polymerase stuttering, with some alternative splicing mechanism is the method of transcription. The virus exits the host cell by nuclear pore export. Horses, sheep, cattle, rodents, birds, and humans serve as the natural host. Transmission routes are fomite, contact, urine, feces, and saliva.[1]
| Genus | Host Details | Tissue Tropism | Entry Details | Release Details | Replication Site | Assembly Site | Transmission |
|---|---|---|---|---|---|---|---|
| Bornavirus | Horses; sheep; cattle; rodents; birds; humans | Neurons; astrocytes; oligodendrocytes; ependymal cells | Clathrin-mediated endocytosis | Budding | Nucleus[3] | Cytoplasm | Fomites; contact: saliva; contact: urine; contact: feces |
Pathogenicity
Between 2011 and 2013, three breeders of variegated squirrels (Sciurus variegatoides) had encephalitis with similar clinical signs and died 2 to 4 months after onset of the clinical symptoms. Genomic analysis found a previously unknown bornavirus in a contact squirrel and in brain tissue from the three men, the researchers reported, and it is the "likely causative agent" in their deaths. Prior to this, Bornavirus species were not thought to be responsible for human diseases.[4][5]
References
- ^ a b c "Viral Zone". ExPASy. Retrieved 12 June 2015.
- ^ a b ICTV. "Virus Taxonomy: 2014 Release". Retrieved 12 June 2015.
- ^ Veterinary Microbiology and microbial disease, 2nd edition, P J Quinn et al. Wiley-Blackwell
- ^ A Variegated Squirrel Bornavirus Associated with Fatal Human Encephalitis
- ^ Zoonotic bornavirus from variegated squirrel tied to fatal CNS infections in German breeders.