Avian coronavirus

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Avian coronavirus
Virus classification Edit this classification
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Pisuviricota
Class: Pisoniviricetes
Order: Nidovirales
Family: Coronaviridae
Genus: Gammacoronavirus
Subgenus: Igacovirus
Avian coronavirus
  • Avian infectious bronchitis virus[1]
  • Infectious bronchitis virus[2]
  • Turkey coronavirus[2]
  • Pheasant coronavirus[2]
  • Duck coronavirus[2]
  • Goose coronavirus[2]
  • Pigeon coronavirus[2]

Avian coronavirus is a species of virus from the genus Gammacoronavirus that infects birds; since 2018, all gammacoronaviruses which infect birds have been classified as this single species.[3] The strain of avian coronavirus previously known as infectious bronchitis virus (IBV) is the only coronavirus that infects chickens.[3] It causes avian infectious bronchitis, a highly infectious disease that affects the respiratory tract, gut, kidney and reproductive system.[4][5] IBV affects the performance of both meat-producing and egg-producing chickens and is responsible for substantial economic loss within the poultry industry.[6] The strain of avian coronavirus previously classified as Turkey coronavirus causes gastrointestinal disease in turkeys.[3]


IBV is in the genus Gammacoronavirus,[7] or group 3,[6] with a non-segmented, positive-sense single-stranded RNA genome.[8]

It was previously the type species of its genus Igacovirus.[9] When there was only one genus of coronaviruses, the genus Coronavirus, it was the type species of the group of all known coronaviruses.[10]


When two strains of coronavirus IBV infect a host they may recombine during genome replication.[11] Recombination appears to contribute to the genetic variation of the IBV genome found in nature.[12][13]


Respiratory system[edit]

When inhaled, virus will attach to glycoprotein receptors containing sialic acid on ciliated epithelial cells of the respiratory epithelium. The respiratory replication will result in loss of ciliary activity,[14] mucus accumulation, necrosis and desquamation, causing respiratory distress, râles and asphyxia. Local virus replication will result in viremia, spreading the infection into other tissues and organs. Other respiratory diseases of chickens (Mycoplasma gallisepticum, avian infectious laryngotracheitis (Gallid alphaherpesvirus 1), Newcastle disease (avian paramyxovirus 1), Avian metapneumovirus infection may be confused clinically to infectious bronchitis.


Through viremia, some nephrotropic strains (most of high virulence) could infect the kidney epithelium in tubules and nephron, causing kidney failure. At gross examination, kidneys may appear swollen and pale in color and with urates in ureters

Reproductive system[edit]

In hens, the viremic IBV will also reach the oviduct, causing lesions in the magnum (the egg-white gland) and in the uterus (the egg-shell gland), leading to a sharp decline of egg production, shell-less, fragile or roughened shells eggs (uterus lesion) with watery whites (magnum lesion). Infection of chickens at puberty, during the oviduct development, will impede oviduct formation and destroy future laying capacity, resulting in "false layers". However, other diseases affecting layer chickens could lead to that condition.[15]


There are both attenuated vaccines and inactivated vaccines available. Their effectiveness is diminished by poor cross-protection. The nature of the protective immune response to IBV is poorly understood, but the surface spike protein, the amino-terminal S1 half, is sufficient to induce good protective immunity. Experimental vector IB vaccines and genetically manipulated IBVs—with heterologous spike protein genes—have produced promising results, including in the context of in ovo vaccination.[6]

See also[edit]


  1. ^ ICTV 7th Report van Regenmortel, M.H.V., Fauquet, C.M., Bishop, D.H.L., Carstens, E.B., Estes, M.K., Lemon, S.M., Maniloff, J., Mayo, M.A., McGeoch, D.J., Pringle, C.R. and Wickner, R.B. (2000). Virus taxonomy. Seventh report of the International Committee on Taxonomy of Viruses. Academic Press, San Diego.1162 pp. https://ictv.global/ictv/proposals/ICTV%207th%20Report.pdf
  2. ^ a b c d e f de Groot, Raoul J.; et al. (2008). "Revision of the family Coronaviridae" (PDF). p. 24. Retrieved 9 March 2020. Avian coronavirus (new) (comprised of existing species infectious bronchitis virus, turkey coronavirus, pheasant coronavirus, duck coronavirus, goose coronavirus, pigeon coronavirus)
  3. ^ a b c de Wit, J.J. Sjaak; Cook, Jane K.A. (August 2020). "Spotlight on avian coronaviruses". Avian Pathology. 49 (4): 313–316. doi:10.1080/03079457.2020.1761010. PMID 32374218.
  4. ^ Casais, R.; Thiel, V.; Siddell, S.G.; Cavanagh, D.; Britton, P. (2001). "Reverse genetics system for the avian coronavirus infectious bronchitis virus". Journal of Virology. 75 (24): 12359–12369. doi:10.1128/JVI.75.24.12359-12369.2001. PMC 116132. PMID 11711626.
  5. ^ Cavanagh, D. (2001). "A nomenclature for avian coronavirus isolates and the question of species status". Avian Pathology. 30 (2): 109–115. doi:10.1080/03079450120044506. PMID 19184884.
  6. ^ a b c Cavanagh, D (2007). "Coronavirus avian infectious bronchitis virus". Veterinary Research. 38 (2): 281–97. doi:10.1051/vetres:2006055. PMID 17296157.Open access icon
  7. ^ Bande, F; Arshad, SS; Omar, AR; Bejo, MH; Abubakar, MS; Abba, Y (2016). "Pathogenesis and diagnostic approaches of Avian Infectious Bronchitis". Advances in Virology. 2016: 4621659. doi:10.1155/2016/4621659. PMC 4756178. PMID 26955391.
  8. ^ de Vries, A.A.F.; Horzinek, M.C.; Rottier, P.J.M.; de Groot., R.J. (1997). "The genome organisation of the Nidovirales: similarities and differences between arteri-, toro-, and coronaviruses". Seminars in Virology. 8 (1): 33–547. CiteSeerX doi:10.1006/smvy.1997.0104. PMC 7128191. PMID 32288441.
  9. ^ "ICTV Taxonomy history: Avian coronavirus". International Committee on Taxonomy of Viruses (ICTV). Retrieved 20 May 2021.
  10. ^ Cann, Alan, ed. (2006). "Coronaviruses". Microbiology @ Leicester. University of Leicester, School of Biological Sciences. Archived from the original on 9 March 2007. Retrieved 15 June 2020. Family: Coronaviridae; (Subfamily): ; Genus: Coronavirus; Type Species: Infectious bronchits virus
  11. ^ Kottier, S.A.; Cavanagh, D; Britton, P (10 November 1995). "Experimental evidence of recombination in coronavirus infectious bronchitis virus". Virology. 213 (2): 569–80. doi:10.1006/viro.1995.0029. PMC 7131336. PMID 7491781.
  12. ^ Wang, L; Junker, D; Collisson, E.W. (February 1993). "Evidence of natural recombination within the S1 gene of infectious bronchitis virus". Virology. 192 (2): 710–6. doi:10.1006/viro.1993.1093. PMID 8380672.
  13. ^ Jia, W; Karaca, K; Parrish, C.R.; Naqi, S.A. (1995). "A novel variant of avian infectious bronchitis virus resulting from recombination among three different strains". Archives of Virology. 140 (2): 259–71. doi:10.1007/BF01309861. PMC 7086685. PMID 7710354.
  14. ^ "Ciliary activity of chicken tracheal epithelial cells". YouTube. 15 November 2010. Archived from the original on 21 December 2021. Retrieved 23 September 2013.
  15. ^ "Infectious Bronchitis: Introduction". The Merck Veterinary Manual. 2006. Archived from the original on 22 June 2007. Retrieved 17 June 2007.

Further reading[edit]