Difference between revisions of "Avian Infectious Bronchitis"
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| − | Also Known As: | + | Also Known As: '''''Infectious Bronchitis''''' |
| − | Caused By: '''''Avian Infectious Bronchitis Virus'' '''also know as:''' ''AIBV | + | Caused By: '''''Avian Infectious Bronchitis Virus'' '''also know as:''' ''AIBV'' — ''IBV'' — ''AIB'' — ''IB''''' |
==Introduction== | ==Introduction== | ||
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IBV is transmitted mainly by '''aerosols''' and also by contaminated people/vehicles/equipment. | IBV is transmitted mainly by '''aerosols''' and also by contaminated people/vehicles/equipment. | ||
| − | It can become ''' | + | It can become '''persistent''' in a bird and recrudesce with '''stress''', e.g. at point of lay. |
| − | |||
| − | |||
==Signalment== | ==Signalment== | ||
| − | Chickens | + | 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. | Disease is most severe in chicks. | ||
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'''Reduced weight gain''' or '''egg production''' and reluctance to move is often the first indicator of disease. | '''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 | + | '''Mortality''' often occurs due to secondary infection, particularly due to [[Escherichia coli|''E. coli'']] and [[:Category:Mycoplasmas|''Mycoplasma'']] infections. |
Respiratory Signs: | Respiratory Signs: | ||
| − | :'''Sneezing, | + | :'''Sneezing, coughing, dyspnoea, tracheal rales''', ingesta present in respiratory passages, nasal discharge, abnormal lung sounds on auscultation |
Alimentary and Urinary Signs: | Alimentary and Urinary Signs: | ||
| − | :''' | + | :'''Wet droppings, dehydration''', polydipsia |
:'''Polyuria, Pollakiuria''' | :'''Polyuria, Pollakiuria''' | ||
| Line 38: | Line 36: | ||
:Conjunctival congestion and increased lacrimation or ocular discharge | :Conjunctival congestion and increased lacrimation or ocular discharge | ||
:'''Soft egg shells''', thin albumin and watery yolks | :'''Soft egg shells''', thin albumin and watery yolks | ||
| − | |||
==Diagnosis== | ==Diagnosis== | ||
| − | In the acute phase, '''viral isolation''' can be attempted from | + | 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. | 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 | + | '''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. | '''Agar Gel Precipitation''' and '''Immunofluorescent Antibody''' (IFAT) tests can also be used to detect the virus. | ||
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The kidneys are '''pale and swollen''' and tubules distended with '''urates''' if nephritis is also present. Heterophilic inflammation and degeneration may be 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 | + | 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. | RT-PCR, VN and HI can also be used to type IBV isolates. | ||
| Line 65: | Line 62: | ||
==Control== | ==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 or sprays. Killed vaccines used alone do not induce immunity and therefore live vaccines are required to prime immunity first. | + | '''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 | + | 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'''. |
Revision as of 06:37, 24 August 2011
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 respiratory system of birds, caused by a coronavirus. The virus can also cause damage to the kidneys and 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 E. coli and 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 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 Agar Gel Immunodiffusion (AGID) , ELISA, Virus Neutralisation (VN) and 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.
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References
Animal Health & Production Compendium, Avian Infectious Bronchitis datasheet, accessed 04/06/2011 @ http://www.cabi.org/ahpc/
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This article was originally sourced from The Animal Health & Production Compendium (AHPC) published online by CABI during the OVAL Project. The datasheet was accessed on 25/06/2011. |
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This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing. |