Flaviviridae
| Flaviviridae | |
|---|---|
| |
| Zika virusvirion structure and genome | |
Virus classification
| |
| (unranked): | Virus |
| Realm: | Riboviria |
| Kingdom: | Orthornavirae |
| Phylum: | Kitrinoviricota |
| Class: | Flasuviricetes |
| Order: | Amarillovirales |
| Family: | Flaviviridae |
| Genera | |
Flaviviridaeis a family ofenvelopedpositive-strand RNA viruseswhich mainly infectmammalsandbirds.[1]They are primarily spread througharthropodvectors(mainlyticksandmosquitoes).[2]The family gets its name from theyellow fevervirus;flavusis Latin for "yellow", and yellow fever in turn was named because of its propensity to causejaundicein victims.[3]There are 89 species in the family divided among four genera.[2]Diseases associated with the group include:hepatitis(hepaciviruses),hemorrhagic syndromes,fatal mucosal disease(pestiviruses),hemorrhagic fever,encephalitis,and the birth defectmicrocephaly(flaviviruses).[4]
Structure
[edit]Virus particles are enveloped and spherical with icosahedral-like geometries that have pseudo T=3 symmetry. They are about 40–60nmin diameter.[2][4]
Genome
[edit] | This section includes a list ofgeneral references,butit lacks sufficient correspondinginline citations.(July 2024) |
Members of the familyFlaviviridaehave monopartite, linear, single-strandedRNAgenomesof positive polarity, and 9.6 to 12.3 kilobase in total length. The 5'-termini of flaviviruses carry amethylatednucleotidecap, while other members of this family are uncapped and encode an internal ribosome entry site.
The genome encodes a single polyprotein with multiple transmembrane domains that is cleaved, by both host and viral proteases, into structural and non-structural proteins. Among the non-structural protein products (NS), the locations and sequences of NS3 and NS5, which contain motifs essential for polyprotein processing and RNA replication respectively, are relatively well conserved across the family and may be useful for phylogenetic analysis.
Life cycle
[edit]
Viral replication is cytoplasmic. Entry into the host cell is achieved by attachment of the viral envelope protein E to host receptors, which mediatesclathrin-mediated endocytosis. Replication follows the positive-stranded RNA virus replication model. Positive-stranded RNA virus transcription is the method of transcription. Translation takes place by viral initiation. The virion assembles by budding through intracellular membranes and exits the host cell by exocytosis.[2][4][5]
| Genus | Host details | Tissue tropism | Entry details | Release details | Replication site | Assembly site | Transmission |
|---|---|---|---|---|---|---|---|
| Flavivirus | Humans; mammals; mosquitoes; ticks | Epithelium: skin; epithelium: kidney; epithelium: intestine; epithelium: testes | Clathrin-mediated endocytosis | Secretion | Cytoplasm | Cytoplasm | Zoonosis; arthropod bite |
| Hepacivirus | Humans | Epithelium: skin; epithelium: kidney; epithelium: intestine; epithelium: testes | Clathrin-mediated endocytosis | Secretion | Cytoplasm | Cytoplasm | Sex; blood |
| Pegivirus | Mammals | None | Clathrin-mediated endocytosis | Secretion | Cytoplasm | Cytoplasm | Unknown |
| Pestivirus | Mammals | None | Clathrin-mediated endocytosis | Secretion | Cytoplasm | Cytoplasm | Vertical: parental |
Host range and evolutionary history
[edit]A wide variety of natural hosts are used by different members of theFlaviviridae,including fish, mammals including humans and various invertebrates, such as those specific to mollusks and crustaceans.[6]The genomes of these flaviviruses show closesyntenywith that of the flavivirus type species, yellow fever virus.[7]One flavivirus, theWenzhou shark flavivirus,infects bothPacific spadenose sharks(Scoliodon macrorhynchos) andGazami crabs(Portunus trituberculatus) with overlapping ranges, raising the possibility of a two-host marine lifecycle.[6]However, another clade of flavivirus, the insect-specific flaviviruses, have genomes that do not demonstrate strong synteny with any of these groups, suggesting a complex evolutionary history.[2][8]
Flavivirusendogenous viral elements,traces of flavivirus genomes integrated into the host's DNA, are found in many species, including a tadpole shrimpLepidurus articus,the water fleaDaphnia magnaand a freshwater jellyfishCraspedacusta sowerbii,[7]suggesting ancient coevolution between animal and flavivirus lineages.[6][7]Many of the well-known members of the family causing disease in vertebrates are transmitted via arthropod vectors (ticks and mosquitoes).[2][4][7]
Taxonomy
[edit]
TheFlaviviridaeare part ofRNA virus supergroup II,which includes certain plant viruses and bacterial viruses.[2]
The family has four genera:[1][2]
- GenusFlavivirus,renamedOrthoflavivirusin 2023, (includesDengue virus,Japanese encephalitis,Kyasanur Forest disease,Powassan virus,West Nile virus,Yellow fever virus,andZika virus)
- GenusHepacivirus(includesHepacivirus C(hepatitis C virus) andHepacivirus B(GB virus B))
- GenusPegivirus(includesPegivirus A(GB virus A),Pegivirus C(GB virus C), andPegivirus B(GB virus D))
- GenusPestivirus(includesPestivirus A(bovine viral diarrhea virus 1) andPestivirus C(classical swine fever virus,previously hog cholera virus)). Viruses in this genus infect nonhuman mammals.
- Unclassified
Other Orthoflaviviruses are known that have yet to be classified. These include Wenling shark virus.
Jingmenvirusis a group of unclassified viruses in the family which includesAlongshan virus,Guaico Culex virus, Jingmen tick virus and Mogiana tick virus. These viruses have a segmented genome of four or five pieces. Two of these segments are derived from flaviviruses.[citation needed]
A number of viruses may be related to the flaviviruses, but have features that are atypical of the flaviviruses. These include citrus Jingmen-like virus, soybean cyst nematode virus 5, Toxocara canis larva agent, Wuhan cricket virus, and possibly Gentian Kobu-sho-associated virus.[citation needed]
Clinical importance
[edit]Major diseases caused by members of the familyFlaviviridaeinclude:
References
[edit]- ^abSimmonds, P; Becher, P; Bukh, J; Gould, E; Meyers, G; Monath, T; Muerhoff, S; Pletnev, A; Rico-Hesse, R; Smith, D; Stapleton, J; ICTV Report Consortium (2017)."ICTV Virus Taxonomy Profile: Flaviviridae".Journal of General Virology.98(1): 2–3.doi:10.1099/jgv.0.000672.PMC5370391.PMID28218572.
- ^abcdefghRicco-Hesse, Rebecca (2023). Knowles, Nick J.; Siddell, Stuart G. (eds.)."Flaviviridae".ICTV Online Report.Retrieved11 July2024.
- ^"Flaviviridae".Microbe Wiki.RetrievedJuly 22,2008.
- ^abcd"Viral Zone".ExPASy.Retrieved11 July2024.
- ^Simmonds P, Becher P, Bukh J, Gould EA, Meyers G, Monath T, Muerhoff S, Pletnet A, Rico-Hesse R, Smith DB, Stapleton JT, ICTV Report Consortium (2017)."ICTV Virus Taxonomy Profile:Flaviviridae".Journal of General Virology.98(1): 2–3.doi:10.1099/jgv.0.000672.PMC5370391.PMID28218572.
- ^abcLensink MJ, Li Y, Lequime S (2022)."Aquatic Flaviviruses".Journal of Virology.96(17): e0043922.doi:10.1128/jvi.00439-22.PMC9472621.PMID35975997.Art. No. e00439-22.
- ^abcdParry R, Asgari S (2019)."Discovery of Novel Crustacean and Cephalopod Flaviviruses: Insights into the Evolution and Circulation of Flaviviruses between Marine Invertebrate and Vertebrate Hosts".Journal of Virology.93(14).doi:10.1128/JVI.00432-19.PMC6600200.PMID31068424.Art. No. e00432-19.
- ^Shi M, Lin XD, Vasilakis N, Tian JH, Li CX, Chen LJ, et al. (2015)."Divergent Viruses Discovered in Arthropods and Vertebrates Revise the Evolutionary History of the Flaviviridae and Related Viruses".Journal of Virology.90(2): 659–669.doi:10.1128/JVI.02036-15.PMC4702705.PMID26491167.
External links
[edit]- ICTV Report:Flaviviridae
- Flaviviridae Genomesdatabase search results from theViral Bioinformatics Resource Center
- Viralzone:Flaviviridae
- Virus Pathogen Database and Analysis Resource (ViPR): Flaviviridae
- "Flaviviridae".NCBI Taxonomy Browser.11050.
