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Avian Infectious Bronchitis (view source)
Revision as of 12:24, 17 August 2012
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{{Podcasts
|link = http://media.bloomsburymediacloud.org/podcasts/wikivet-english/avian-infectious-bronchitis}}
Also Known As: '''''Infectious Bronchitis'''''
Caused By: '''''Avian Infectious Bronchitis Virus'' '''also know as:''' ''AIBV'' — ''IBV'' — ''AIB'' — ''IB'''''
==Introduction==
Avian Infectious Bronchitis is a '''highly contagious''' viral disease primarily of the '''[[:Category:Avian Respiratory System - Anatomy & Physiology|respiratory system]]''' of birds, caused by a '''[[Coronaviridae | coronavirus]]'''.
The virus can also cause damage to the '''[[Exotic Urinary System - Anatomy & Physiology#Avian|kidneys]]''' and '''[[Avian Female Reproductive System|oviducts]]'''.
IBV is transmitted mainly by '''aerosols''' and also by contaminated people/vehicles/equipment.
It can become '''persistent''' in a bird and recrudesce with '''stress''', e.g. at point of lay.
==Signalment==
Chickens are the only known natural host of IBV. Other birds are affected by genetically similar yet distinct avian coronaviruses.
Disease is most severe in chicks.
==Distribution==
Worldwide
==Clinical Signs==
'''Reduced weight gain''' or '''egg production''' and reluctance to move is often the first indicator of disease.
'''Mortality''' often occurs due to secondary infection, particularly due to [[Escherichia coli|''E. coli'']] and [[:Category:Mycoplasmas|''Mycoplasma'']] infections.
Respiratory Signs:
:'''Sneezing, coughing, dyspnoea, tracheal rales''', ingesta present in respiratory passages, nasal discharge, abnormal lung sounds on auscultation
Alimentary and Urinary Signs:
:'''Wet droppings, dehydration''', polydipsia
:'''Polyuria, Pollakiuria'''
Other Signs:
:Reluctance to move
:Swelling of the head and face
:Conjunctival congestion and increased lacrimation or ocular discharge
:'''Soft egg shells''', thin albumin and watery yolks
==Diagnosis==
In the acute phase, '''viral isolation''' can be attempted from tracheal swabs or tracheal/lung biopsies.
If more than one week after initial infection, caecal tonsils or cloacal swabs are more reliable.
'''RT-PCR''' can be performed on buccal or oropharyngeal swabs.
'''Agar Gel Precipitation''' and '''Immunofluorescent Antibody''' (IFAT) tests can also be used to detect the virus.
On '''post-mortem examination''', '''yellow catarrhal or caseous exudates''' are present in the trachea, nasal passages, sinuses and air sacs.
On histopathology of the trachea, loss of cilia and sloughing with '''[[Heterophils |heterophilic infiltration]]''' is evident.
The kidneys are '''pale and swollen''' and tubules distended with '''urates''' if nephritis is also present. Heterophilic inflammation and degeneration may be evident.
Detection of '''viral antibodies''' is also valuable in surveillance and monitoring of vaccination. This can be performed using [[Immunodiffusion|'''Agar Gel Immunodiffusion''' (AGID)]] , [[ELISA testing |ELISA]], Virus Neutralisation (VN) and [[Agglutination|Haemagglutination-Inhibition (HI)]].
RT-PCR, VN and HI can also be used to type IBV isolates.
==Treatment==
'''No treatment''' is available for the viral infection.
Use of '''antibiotics''' in drinking water to treat and prevent secondary infection may reduce mortality and losses.
==Control==
'''Live and Killed IBV vaccines''' are available and widely used but cross-protection is poor and numerous serotypes exist so disease is not always prevented. Vaccinations can be administered as intra-muscular injections (killed vaccines) or sprays/drinking water (live vaccines). Killed vaccines used alone do not induce immunity and therefore live vaccines are required to prime immunity first.
Good '''biosecurity''' and '''hygiene''' protocols are imperative to control this highly contagious disease. Particular efforts should be made with respect to '''ventilation''' and '''air quality'''.
{{Learning
|literature search = [http://www.cabdirect.org/search.html?q=title%3A+%28Avian+Infectious+Bronchitis%29/ Avian Infectious Bronchitis Publications]
|flashcards = [[Avian Infectious Bronchitis Flashcards]]
}}
==References==
Cavanagh, D. and Gelb Jr, J. (2008) '''Infectious Bronchitis'''. In: '''Diseases of Poultry, 12th Edition''' (eds. Saif, Y.M., Fadly A.M., Glissen J.R., McDougald L.R., Nolan L.K., Swayne D.E.) ''Wiley-Blackwell'', pp 117-135
Cook, J.K.A. (2007) '''Coronaviridae'''. In: '''Poultry Diseases, 6th Edition''' (eds. Pattison, M., McMullin, P., Bradbury, J., Alexander, D.) ''Saunders, Elsevier'', pp 340-350
Animal Health & Production Compendium, '''Avian Infectious Bronchitis datasheet''', accessed 04/06/2011 @ http://www.cabi.org/ahpc/
{{CABI source
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=92907&loadmodule=datasheet&page=2144&site=160 avian infectious bronchitis] and [http://www.cabi.org/ahpc/?compid=3&dsid=92904&loadmodule=datasheet&page=2144&site=160 avian infectious bronchitis virus]
|date = 25/06/2011
}}
<br><br>
{{Dave Cavanagh
|date = 23 August 2011
}}
{{OpenPages}}
[[Category:Respiratory Diseases - Birds]]
[[Category:Avian Viruses]]
[[Category:Coronaviridae]]
[[Category:CABI Expert Review Completed]][[Category:CABI AHPC Pages]]