Circovirus
Circovirus is a genus of viruses, in the family Circoviridae. Birds (such as pigeons[1] and ducks[2]) and pigs[3] serve as natural hosts, though dogs have been shown to be infected as well.[4] There are currently 43 species in this genus including the type species Porcine circovirus 1. Some members of this genus cause disease: PCV-1 is non pathogenic, while PCV-2 causes postweaning multisystemic wasting syndrome (PMWS).[5][6]
| Circovirus | |
|---|---|
Virus classification  | |
| (unranked): | Virus |
| Realm: | Monodnaviria |
| Kingdom: | Shotokuvirae |
| Phylum: | Cressdnaviricota |
| Class: | Arfiviricetes |
| Order: | Cirlivirales |
| Family: | Circoviridae |
| Genus: | Circovirus |
| Type species | |
| Porcine circovirus 1 | |
Taxonomy
The following species are recognized:
- Barbel circovirus
- Bat associated circovirus 1
- Bat associated circovirus 2
- Bat associated circovirus 3
- Bat associated circovirus 4
- Bat associated circovirus 5
- Bat associated circovirus 6
- Bat associated circovirus 7
- Bat associated circovirus 8
- Bat associated circovirus 9
- Bat associated circovirus 10
- Bat associated circovirus 11
- Bat associated circovirus 12
- Beak and feather disease virus
- Canary circovirus
- Canine circovirus
- Chimpanzee associated circovirus 1
- Civet circovirus
- Duck circovirus
- European catfish circovirus
- Finch circovirus
- Goose circovirus
- Gull circovirus
- Human associated circovirus 1
- Mink circovirus
- Mosquito associated circovirus 1
- Pigeon circovirus
- Porcine circovirus 1
- Porcine circovirus 2
- Porcine circovirus 3
- Raven circovirus
- Rodent associated circovirus 1
- Rodent associated circovirus 2
- Rodent associated circovirus 3
- Rodent associated circovirus 4
- Rodent associated circovirus 5
- Rodent associated circovirus 6
- Rodent associated circovirus 7
- Starling circovirus
- Swan circovirus
- Tick associated circovirus 1
- Tick associated circovirus 2
- Zebra finch circovirus
Structure
Viruses in Circovirus are non-enveloped, with icosahedral and Round geometries, and T=1 symmetry. The diameter is around 17 nm. Genomes are circular and non-segmented.[5]
The virions of Circoviruses are surprisingly small, with diameters ranging from 17 up to 22 nm.[7]
| Genus | Structure | Symmetry | Capsid | Genomic arrangement | Genomic segmentation |
|---|---|---|---|---|---|
| Circovirus | Icosahedral | T=1 | Non-enveloped | Circular | Monopartite |
Life cycle
Viral replication is nuclear. Entry into the host cell is achieved by penetration. Replication follows the ssDNA rolling circle model. DNA templated transcription, with some alternative splicing mechanism is the method of transcription. The virus exits the host cell by nuclear egress, and nuclear pore export. Birds and pigs serve as the natural host. Transmission routes are fecal-oral and parental.[5]
| Genus | Host details | Tissue tropism | Entry details | Release details | Replication site | Assembly site | Transmission |
|---|---|---|---|---|---|---|---|
| Circovirus | Birds; pigs | None | Cell receptor endocytosis | Budding | Nucleus | Nucleus | Horizontal; oral-fecal |
References
- Marlier, D; Vindevogel, H (July 2006). "Viral infections in pigeons". Veterinary Journal (London, England : 1997). 172 (1): 40–51. doi:10.1016/j.tvjl.2005.02.026. PMID 16772130.
- Zhang, XX; Liu, SN; Xie, ZJ; Kong, YB; Jiang, SJ (June 2012). "Complete genome sequence analysis of duck circovirus strains from Cherry Valley duck". Virologica Sinica. 27 (3): 154–64. doi:10.1007/s12250-012-3214-4. PMID 22684469.
- Chae, C (March 2012). "Porcine circovirus type 2 and its associated diseases in Korea". Virus Research. 164 (1–2): 107–13. doi:10.1016/j.virusres.2011.10.013. PMID 22027190.
- Vogelsang, Jessica (September 14, 2013). "5 Things You Need to Know About the 'Circovirus Outbreak'". Yahoo News.
- "Viral Zone". ExPASy. Retrieved 15 June 2015.
- ICTV. "Virus Taxonomy: 2014 Release". Retrieved 15 June 2015.
- "Circovirus – microbewiki".