infectious bronchitis virus

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{{Virusbox

| name = Infectious bronchitis virus

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| parent = Igacovirus

| species = Gammacoronavirus galli

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Avian coronavirus
Avian infectious bronchitis virusICTV 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
Infectious bronchitis virus{{cite web |last1=de Groot |first1=Raoul J. |display-authors=etal |title=Revision of the family Coronaviridae |url=https://ictv.global/ictv/proposals/2008.085-122V.v4.Coronaviridae.pdf |access-date=9 March 2020 |page=24 |language=en |date=2008 |quote=Avian coronavirus (new) ({{sic|comprised |hide=y|of}} existing species infectious bronchitis virus, turkey coronavirus, pheasant coronavirus, duck coronavirus, goose coronavirus, pigeon coronavirus)}}
Turkey coronavirus
Pheasant coronavirus
Duck coronavirus
Goose coronavirus
Pigeon coronavirus

}}

Infectious bronchitis virus (IBV) is a species of virus from the genus Gammacoronavirus that infects birds.{{cite journal |last1=de Wit |first1=J.J. Sjaak |last2=Cook |first2=Jane K.A. |title=Spotlight on avian coronaviruses |journal=Avian Pathology |date=August 2020 |volume=49 |issue=4 |pages=313–316 |doi=10.1080/03079457.2020.1761010 |doi-access=free |pmid=32374218}} It causes avian infectious bronchitis, a highly infectious disease that affects the respiratory tract, gut, kidney and reproductive system.{{cite journal| author=Casais, R.| author2=Thiel, V.| author3=Siddell, S.G.| author4=Cavanagh, D.| author5=Britton, P. |year=2001 |title=Reverse genetics system for the avian coronavirus infectious bronchitis virus |journal=Journal of Virology |volume=75|pages=12359–12369 |doi=10.1128/JVI.75.24.12359-12369.2001| pmid=11711626| issue=24| pmc=116132}}{{cite journal| author=Cavanagh, D. |year=2001 |title=A nomenclature for avian coronavirus isolates and the question of species status |journal=Avian Pathology |volume=30|pages=109–115 |doi=10.1080/03079450120044506| pmid=19184884| issue=2|doi-access=free }} IBV affects the performance of both meat-producing and egg-producing chickens and is responsible for substantial economic loss within the poultry industry.

Classification

IBV is in the genus Gammacoronavirus,{{cite journal|last1=Bande|first1=F|last2=Arshad|first2=SS|last3=Omar|first3=AR|last4=Bejo|first4=MH|last5=Abubakar|first5=MS|last6=Abba|first6=Y|title=Pathogenesis and diagnostic approaches of Avian Infectious Bronchitis|journal=Advances in Virology|date=2016|volume=2016|pages=4621659|doi=10.1155/2016/4621659|pmid=26955391|pmc=4756178|doi-access=free}} or group 3,{{cite journal|last1=Cavanagh|first1=D|title=Coronavirus avian infectious bronchitis virus|journal=Veterinary Research|date=2007|volume=38|issue=2|pages=281–97|doi=10.1051/vetres:2006055|pmid=17296157|doi-access=free}}{{open access}} with a non-segmented, positive-sense single-stranded RNA genome.{{cite journal|author1=de Vries, A.A.F. |author2=Horzinek, M.C. |author3=Rottier, P.J.M. |author4=de Groot., R.J. |year=1997 |title=The genome organisation of the Nidovirales: similarities and differences between arteri-, toro-, and coronaviruses. |journal=Seminars in Virology |volume=8 |issue=1 |pages=33–547 |doi=10.1006/smvy.1997.0104|pmid=32288441 |pmc=7128191 |citeseerx=10.1.1.462.1825 }}

It was previously the type species of its genus Igacovirus.{{cite web |url=https://ictv.global/taxonomy/taxondetails?taxnode_id=202001880 |title=ICTV Taxonomy history: Avian coronavirus |publisher=International Committee on Taxonomy of Viruses (ICTV) |access-date=20 May 2021}} When there was only one genus of coronaviruses, the genus Coronavirus, it was the type species of the group of all known coronaviruses.{{cite encyclopedia |editor-last=Cann |editor-first=Alan |encyclopedia=Microbiology @ Leicester |title=Coronaviruses |url=http://www-micro.msb.le.ac.uk/3035/Coronaviruses.html |access-date=2020-06-15 |year=2006 |publisher=University of Leicester, School of Biological Sciences |archive-url=https://web.archive.org/web/20070309144307/http://www-micro.msb.le.ac.uk/3035/Coronaviruses.html |archive-date=2007-03-09 |quote=Family: Coronaviridae; (Subfamily): ; Genus: Coronavirus; Type Species: Infectious bronchits virus}}

Recombination

When two strains of coronavirus IBV infect a host they may recombine during genome replication.{{cite journal |last1=Kottier |first1=S.A. |last2=Cavanagh |first2=D |last3=Britton |first3=P |title=Experimental evidence of recombination in coronavirus infectious bronchitis virus. |journal=Virology |date=10 November 1995 |volume=213 |issue=2 |pages=569–80 |doi=10.1006/viro.1995.0029 |doi-access=free |pmid=7491781 |pmc=7131336}} Recombination appears to contribute to the genetic variation of the IBV genome found in nature.{{cite journal |last1=Wang |first1=L |last2=Junker |first2=D |last3=Collisson |first3=E.W. |title=Evidence of natural recombination within the S1 gene of infectious bronchitis virus. |journal=Virology |date=February 1993 |volume=192 |issue=2 |pages=710–6 |doi=10.1006/viro.1993.1093 |pmid=8380672}}{{cite journal |last1=Jia |first1=W |last2=Karaca |first2=K |last3=Parrish |first3=C.R. |last4=Naqi |first4=S.A. |title=A novel variant of avian infectious bronchitis virus resulting from recombination among three different strains. |journal=Archives of Virology |date=1995 |volume=140 |issue=2 |pages=259–71 |doi=10.1007/BF01309861 |doi-access=free |pmid=7710354 |pmc=7086685}}

Pathology

= Respiratory system =

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,{{cite web|url=https://www.youtube.com/watch?v=40Vxq5I22pM |archive-url=https://ghostarchive.org/varchive/youtube/20211221/40Vxq5I22pM |archive-date=2021-12-21 |url-status=live|title=Ciliary activity of chicken tracheal epithelial cells |publisher=YouTube |date=2010-11-15 |access-date=2013-09-23}}{{cbignore}} 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.

=Kidney =

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 =

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.{{cite web|title=Infectious Bronchitis: Introduction |work=The Merck Veterinary Manual |year=2006 |url=http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/206500.htm |access-date=2007-06-17 |archive-url=https://web.archive.org/web/20070622113318/http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm%2Fbc%2F206500.htm |archive-date=22 June 2007 |url-status=live }}

Vaccines

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.