Changes

Also Known As: '''''Infectious Coryza''''' — '''''Infectious Bronchitis''''' — '''''Infectious Proventriculitis''''' — '''''Avian Infectious Nephrosis'''''

Also Known As: '''''Infectious Bronchitis'''''

Caused By: '''''Avian Infectious Bronchitis Virus'' '''also know as:''' ''AIBV'' — ''ICTV'' — ''IBV'' — ''AIB'' — ''IB'''''

Caused By: '''''Avian Infectious Bronchitis Virus'' '''also know as:''' ''AIBV'' — ''IBV'' — ''AIB'' — ''IB'''''

==Introduction==

==Introduction==

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 '''latent''' in a bird and recrudesce with '''stress''', e.g. at point of lay.

It can become '''persistent''' in a bird and recrudesce with '''stress''', e.g. at point of lay.

 

This disease is notifiable to the World Organisation for Animal Health [http://www.oie.int/ (OIE)].

==Signalment==

==Signalment==

Chickens, pigeons and pheasants are affected.

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.

'''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 is highest in intensively reared broiler flocks.

'''Mortality''' often occurs due to secondary infection, particularly due to [[Escherichia coli|''E. coli'']] and [[:Category:Mycoplasmas|''Mycoplasma'']] infections.

Respiratory Signs:

Respiratory Signs:

:'''Sneezing, Coughing, Dyspnoea''', Ingesta present in respiratory passages, Nasal discharge, Abnormal lung sounds on auscultation

:'''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:

:'''Diarrhoea, dehydration''', polydipsia

:'''Wet droppings, dehydration''', polydipsia

:'''Polyuria, Pollakiuria'''

:'''Polyuria, Pollakiuria'''

: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 eggs, tracheal swabs or tracheal/lung biopsies.  

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 but will not differentiate live from dead virus isolate.

'''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.

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, monitoring of vaccination and identification of latently infected birds. This can be performed using [[Immunodiffusion|'''Agar Gel Immunodiffusion''' (AGID)]] , [[ELISA testing |ELISA]], Virus Neutralisation (VN) and [[Agglutination|Haemagglutination-Inhibition (HI)]].

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.

==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 of this highly contagious disease. Particular efforts should be made with respect to '''ventilation''' and '''air quality'''.

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'''.