Lyssavirus

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Lyssavirus
CSIRO ScienceImage 1977 Bat Lyssavirus.jpg
Colored transmission electron micrograph of Australian bat lyssavirus. The bullet-like objects are the virions, and some of them are budding off from a cell.
Virus classification OOjs UI icon edit-ltr.svg
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Negarnaviricota
Class: Monjiviricetes
Order: Mononegavirales
Family: Rhabdoviridae
Genus:Lyssavirus
Species

See text

Lyssavirus (from the Greek λύσσαlyssa "rage, fury, rabies" and the Latin vīrus ) [1] [2] is a genus of RNA viruses in the family Rhabdoviridae , order Mononegavirales . Mammals, including humans, can serve as natural hosts. [3] The genus Lyssavirus includes the causative agent (rabies virus) of rabies. [4]

Contents

Taxonomy

The genus contains the following species, listed by scientific name and followed by the exemplar virus of the species: [5]

Virology

Structure

Lyssavirions are enveloped, with bullet shaped geometries. These virions are about 75 nm wide and 180 nm long. [3] Lyssavirions have helical symmetry, so their infectious particles are approximately cylindrical in shape. This is typical of plant-infecting viruses. Virions of human-infecting viruses more commonly have cubic symmetry and take shapes approximating regular polyhedra.[ citation needed ]

The structure consists of a spiked outer envelope, a middle region consisting of matrix protein M, and an inner ribonucleocapsid complex region, consisting of the genome associated with other proteins.[ citation needed ]

Genome

Lyssavirus genomes consist of a negative-sense, single-stranded RNA molecule that encodes five viral proteins: polymerase L, matrix protein M, phosphoprotein P, nucleoprotein N, and glycoprotein G. Genomes are linear, around 11kb in length. [3]

Based on recent phylogenetic evidence, lyssaviruses have been categorized into seven major species. In addition, five more species have recently been discovered: West Caucasian bat virus, Aravan virus, Khujand virus, Irkut virus and Shimoni bat virus. [6] [7] The lyssavirus genus can be divided into four phylogroups based upon DNA sequence homology. Phylogroup I includes viruses, such as Rabies virus, Duvenhage virus, European bat lyssavirus types 1 and 2, Australian bat lyssavirus, Khujand virus, Bokeloh bat lyssavirus, Irkut virus, and Aravan virus. Phylogroup II contains Lagos bat virus, Mokola virus, and Shimoni bat virus. West Caucasian bat lyssavirus is the only virus that is a part of phylogroup III. Ikoma lyssavirus and Lleida bat lyssavirus are examples in phylogroup IV. West Caucasian bat lyssavirus was classified within its own phylogroup because it is the most divergent lyssavirus that has been discovered. [8]

GenusStructureSymmetryCapsidGenomic arrangementGenomic segmentation
LyssavirusBullet-shapedEnvelopedLinearMonopartite

Evolution

Phylogenetic studies suggest that the original hosts of these viruses were bats. [9] However, the recent discovery of lyssavirus sequences from amphibians and reptiles challenges the mammalian origin of lyssaviruses. [10] [11] The greater antigenic diversity of lyssaviruses from Africa has led to the assumption that Africa was the origin of these viruses. An examination of 153 viruses collected between 1956 and 2015 from various geographic locations has instead suggested a Palearctic origin (85% likelihood) for these viruses. [12] Date estimates (95% likelihood) for the most recent common ancestor were very broad – between 3,995 and 166,820 years before present – which suggests there is further work to be done in this area. Although bats evolved in the Palearctic, [13] their origins antedate that of the lyssaviruses by millions of years, which argues against their co-speciation. The evolution rate in the N gene in the Africa 2 lineage has been estimated to be 3.75×10−3 substitutions per site per year. [14] This rate is similar to that of other RNA viruses.

Life cycle

Viral replication is cytoplasmic. Entry into the host cell is achieved by attachment of the viral G 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, is the method of transcription. The virus exits the host cell by budding and by tubule-guided viral movement. Wild mammals, especially bats and certain carnivores, serve as natural hosts. Transmission routes are typically via bite wounds. [3]

GenusHost detailsTissue tropismEntry detailsRelease detailsReplication siteAssembly siteTransmission
Lyssavirusbats, Crocidura shrews and certain carnivoresNeuronsClathrin-mediated endocytosisBuddingCytoplasmCytoplasmBite wounds

Testing

As of 2018 the direct fluorescent antibody (DFA) test is still the gold standard to detect lyssavirus infection. Since the new millennium reverse transcription PCR (RT-PCR) tests have been developed for rabies but only been used as a confirmatory test. Real-time PCR-based tests which have higher sensitivity and objective diagnostic thresholds and allow samples to be stored at room temperature have been promising since 2005, but require a real-time PCR machine and skilled workers with experience in molecular diagnostics. In an international evaluation a single TaqMan LN34 assay could detect Lyssavirus with high sensitivity (99.90%) across the genus and high specificity (99.68%) when compared to the DFA test. It will become the primary post-mortem rabies diagnostic test where possible. [15]

Epidemiology

Classic rabies virus is prevalent throughout most of the world and can be carried by any warm blooded mammal. The other lyssaviruses have much less diversity in carriers. Only select hosts can carry each of these viral species. Also, these other species are particular only to a specific geographic area. Bats are known to be an animal vector for all identified lyssaviruses except the Mokola virus. [16]

See also

References

  1. λύσσα . Liddell, Henry George ; Scott, Robert ; A Greek–English Lexicon at the Perseus Project.
  2. vīrus . Charlton T. Lewis and Charles Short. A Latin Dictionary on Perseus Project .
  3. 1 2 3 4 "Viral Zone". ExPASy . Retrieved 15 June 2015.
  4. "Virus - Annotated classification". Britannica. 18 June 2024.
  5. "Virus Taxonomy: 2024 Release". International Committee on Taxonomy of Viruses. Retrieved 15 March 2025.
  6. Virus Taxonomy: 2013 Release. ictvonline.org
  7. Kuzmin IV, Hughes GJ, Botvinkin AD, Orciari LA, Rupprecht CE (July 2005). "Phylogenetic relationships of Irkut and West Caucasian bat viruses within the Lyssavirus genus and suggested quantitative criteria based on the N gene sequence for lyssavirus genotype definition". Virus Research. 111 (1): 28–43. doi:10.1016/j.virusres.2005.03.008. PMID   15896400.
  8. Gould AR, Kattenbelt JA, Gumley SG, Lunt RA (October 2002). "Characterisation of an Australian bat lyssavirus variant isolated from an insectivorous bat". Virus Research. 89 (1): 1–28. doi:10.1016/s0168-1702(02)00056-4. PMID   12367747.
  9. Banyard AC, Hayman D, Johnson N, McElhinney L, Fooks AR (2011). "Bats and lyssaviruses". Advances in Virus Research. 79: 239–289. doi:10.1016/B978-0-12-387040-7.00012-3. ISBN   978-0-12-387040-7. PMID   21601050.
  10. Oberhuber M, Schopf A, Hennrich AA, Santos-Mandujano R, Huhn AG, Seitz S, Riedel C, Conzelmann KK (September 2021). "Glycoproteins of Predicted Amphibian and Reptile Lyssaviruses Can Mediate Infection of Mammalian and Reptile Cells". Viruses. 13 (9): 1726. doi: 10.3390/v13091726 . PMC   8473393 . PMID   34578307.
  11. Horie M, Akashi H, Kawata M, Tomonaga K (1 February 2021). "Identification of a reptile lyssavirus in Anolis allogus provided novel insights into lyssavirus evolution". Virus Genes. 57 (1): 40–49. doi:10.1007/s11262-020-01803-y. PMID   33159637. S2CID   226276694.
  12. Hayman DT, Fooks AR, Marston DA, Garcia-R JC (December 2016). "The Global Phylogeography of Lyssaviruses - Challenging the 'Out of Africa' Hypothesis". PLOS Neglected Tropical Diseases. 10 (12): e0005266. doi: 10.1371/journal.pntd.0005266 . PMC   5231386 . PMID   28036390.
  13. Teeling EC, Springer MS, Madsen O, Bates P, O'brien SJ, Murphy WJ (January 2005). "A molecular phylogeny for bats illuminates biogeography and the fossil record". Science. 307 (5709): 580–584. Bibcode:2005Sci...307..580T. doi:10.1126/science.1105113. PMID   15681385. S2CID   25912333.
  14. He W, Zhang H, Zhang Y, Wang R, Lu S, Ji Y, et al. (October 2017). "Codon usage bias in the N gene of rabies virus". Infection, Genetics and Evolution. 54: 458–465. doi:10.1016/j.meegid.2017.08.012. PMID   28818621.
  15. Gigante CM, Dettinger L, Powell JW, Seiders M, Condori RE, Griesser R, et al. (16 May 2018). "Multi-site evaluation of the LN34 pan-lyssavirus real-time RT-PCR assay for post-mortem rabies diagnostics". PLOS ONE. 13 (5): e0197074. Bibcode:2018PLoSO..1397074G. doi: 10.1371/journal.pone.0197074 . PMC   5955534 . PMID   29768505.
  16. WHO Rabnet/CDC Map Production (2008). "Rabies, countries or areas at risk". World Health Organization. Archived from the original on 9 October 2010.

Further reading