Circovirus Explained

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] It is a single stranded DNA virus (ssDNA). There are 49 species in this genus. Some members of this genus cause disease: PCV-1 is non pathogenic, while PCV-2 causes postweaning multisystemic wasting syndrome (PMWS).[5] [6]

Taxonomy

The following species are recognized:

Structure

Viruses in Circovirus are non-enveloped, with icosahedral and round geometries, and T=1 symmetry.[7] The diameter is around 17 nm. Genomes are circular and non-segmented.

The virions of Circoviruses are surprisingly small, with diameters ranging from 17 up to 22 nm.[8]

Genus Structure Symmetry !Capsid Genomic arrangement Genomic segmentation
CircovirusIcosahedralT=1Non-envelopedCircularMonopartite

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.[9] The virus is known to cause "immunosuppressive conditions" in animals that are infected; as well as having the ability to jump between species, creating difficulty in identifying the origin of infection.[10] [11] [12] [13] [14] Transmission routes are fecal-oral and parental.

Genome

Circovirus has a monopartite, circular, and ssDNA genome of between 1759 and 2319nt, making it possibly the virus of shortest genome size in mammal viruses. The virus replicates through an dsDNA intermediate initiated by the Rep protein. Two major genes are transcribed from open reading frame (ORF) 1 and 2. ORF1 encodes Rep and Rep' for initiation of rolling-circle replication; ORF2 encodes Cap, the only structural and most immunogenic protein forming the viral capsid.[15]

External links

Notes and References

  1. Marlier D, Vindevogel H . Viral infections in pigeons . Veterinary Journal . 172 . 1 . 40–51 . July 2006 . 16772130 . 10.1016/j.tvjl.2005.02.026 .
  2. Zhang XX, Liu SN, Xie ZJ, Kong YB, Jiang SJ . Complete genome sequence analysis of duck circovirus strains from Cherry Valley duck . Virologica Sinica . 27 . 3 . 154–164 . June 2012 . 22684469 . 8218041 . 10.1007/s12250-012-3214-4 .
  3. Chae C . Porcine circovirus type 2 and its associated diseases in Korea . Virus Research . 164 . 1–2 . 107–113 . March 2012 . 22027190 . 10.1016/j.virusres.2011.10.013 .
  4. News: 5 Things You Need to Know About the 'Circovirus Outbreak'. Vogelsang J . Yahoo News. September 14, 2013.
  5. Web site: Circovirus . Viral Zone. ExPASy. 15 June 2015.
  6. Web site: Circovirus Family: Circoviridae . Virus Taxonomy: 2020 Release . International Committee on Taxonomy of Viruses (ICTV) . March 2021 . 11 May 2021.
  7. Tarján ZL, Szekeres S, Vidovszky MZ, Egyed L . Detection of circovirus in free-ranging brown rats (Rattus norvegicus) . Infection, Genetics and Evolution . 118 . 105548 . March 2024 . 38176604 . 10.1016/j.meegid.2023.105548 . free .
  8. Web site: Circovirus . MicrobeWiki . Barich D . Department of Biology, Kenyon College .
  9. Opriessnig T, Karuppannan AK, Castro AM, Xiao CT . Porcine circoviruses: current status, knowledge gaps and challenges . Virus Research . 286 . 198044 . September 2020 . 32502553 . 10.1016/j.virusres.2020.198044 . 20.500.11820/5656bbcb-1051-411e-a955-ce4e25583860 . 219398908 . free .
  10. Lorincz M, Cságola A, Biksi I, Szeredi L, Dán A, Tuboly T . Detection of porcine circovirus in rodents - short communication . Acta Veterinaria Hungarica . 58 . 2 . 265–268 . June 2010 . 20460225 . 10.1556/avet.58.2010.2.12 .
  11. Pinheiro AL, Bulos LH, Onofre TS, de Paula Gabardo M, de Carvalho OV, Fausto MC, Guedes RM, de Almeida MR, Silva Júnior A . Verification of natural infection of peridomestic rodents by PCV2 on commercial swine farms . Research in Veterinary Science . 94 . 3 . 764–768 . June 2013 . 23141170 . 10.1016/j.rvsc.2012.10.006 .
  12. Truong QL, Seo TW, Yoon BI, Kim HC, Han JH, Hahn TW . Prevalence of swine viral and bacterial pathogens in rodents and stray cats captured around pig farms in Korea . The Journal of Veterinary Medical Science . 75 . 12 . 1647–1650 . December 2013 . 23892461 . 3942947 . 10.1292/jvms.12-0568 .
  13. Zhai SL, Chen SN, Liu W, Li XP, Deng SF, Wen XH, Luo ML, Lv DH, Wei WK, Chen RA . Molecular detection and genome characterization of porcine circovirus type 2 in rats captured on commercial swine farms . Archives of Virology . 161 . 11 . 3237–3244 . November 2016 . 27530112 . 10.1007/s00705-016-3004-7 . 254052514 .
  14. Zhao M, Bao S, Xu D, He J, Zhang H, Ji L, Yang S, Wang X, Shen Q, Liu J, Zhang Q, Ma X, Zhang W, Shan T . Virome of wild rats (Rattus norvegicus) captured far from pig farms in Jiangsu province of China reveals novel porcine circovirus type 2d (PCV2d) sequences . Virology Journal . 20 . 1 . 46 . March 2023 . 36894948 . 9997004 . 10.1186/s12985-023-02005-2 . free .
  15. Book: Mankertz A . Circoviruses . January 2008 . https://www.sciencedirect.com/science/article/pii/B9780123744104007020 . Encyclopedia of Virology . Third . 513–519 . Mahy BW, Van Regenmortel MH . 2023-10-04 . Oxford . Academic Press . 10.1016/b978-012374410-4.00702-0 . 978-0-12-374410-4 .

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