Changes

{{Taxobox

{{Taxobox

|name              = Avian Adenoviruses

|name              = Avian Adenoviruses

|sub-order          =

|sub-order          =

|super-family      =

|super-family      =

|family            = Adenoviridae

|family            = [[Category:Adenoviridae|Adenoviridae]]

|sub-family        =

|sub-family        =

|genus              = Aviadenovirus

|genus              = Aviadenovirus

|species            = Avian adenoviridae

|species            = Avian adenoviridae

}}

}}

==Introduction==

==Introduction==

Avian adenoviruses affect '''chickens, ducks, geese, turkeys and pheasants worldwide.'''

Avian adenoviruses affect '''chickens, ducks, geese, turkeys and pheasants worldwide.'''

Avian adenoviruses are easy to identify microscopically by their '''icosahedral shape''' and triangular facets of capsomeres. <ref>McCracken, R. M., Adair, B. M (1993) '''Avian adenoviruses'''.Virus infections of birds. 123-144; 89</ref>

Avian adenoviruses are easy to identify microscopically by their '''icosahedral shape''' and triangular facets of capsomeres. Many species of adenovirus can be found on one farm or even within one bird.

 

Many species of adenovirus can be found on one farm or even within one bird.

Avian adenoviruses are highly species specific and not zoonotic.

Avian adenoviruses are not zoonotic.

==Lifecycle==

==Lifecycle==

Incidence of adenovirus infection approaches '''100% in most countries''' and many infections are subclinical. Most infections present as maternal immunity declines allowing viral replication to increase around '''4-6 weeks of age'''.

Incidence of adenovirus infection approaches '''100% in most countries''' and many infections are subclinical. Most infections present as maternal immunity declines allowing viral replication to increase around '''4-6 weeks of age'''.

Specific syndromes associated with avian adenoviruses include '''Quail bronchitis (QB), Egg Drop Syndrome (EDS), Haemorrhagic Enteritis (HE), Pheasant Marble Spleen Disease (MSD) and Inclusion Body Hepatitis (IBH)''', of which EDS and HE are among the most important avian diseases globally.

Specific syndromes associated with avian adenoviruses include '''Quail Bronchitis (QB), Egg Drop Syndrome (EDS), Haemorrhagic Enteritis (HE), Pheasant Marble Spleen Disease (MSD) and Inclusion Body Hepatitis (IBH)''', of which EDS and HE are among the most important avian diseases globally.

Multisystemic disease can affect the respiratory, nervous, reproductive and musculoskeletal systems.

Multisystemic disease can affect the respiratory, nervous, reproductive and musculoskeletal systems.

==Diagnosis==

==Diagnosis==

'''Virus isolation and histopathology'' should be performed on the main site of replication which will vary with disease and virus species as discussed in clinical signs. '''Intranuclear inclusion bodies''' are common and suggestive but not specific to adenoviruses. The virus can be innoculated into cell cultures and easily identified by '''electron microscopy or staining with fluorescent antisera'''. Serum neutralisation can be used to determine individual species using standard antisera.

'''Virus isolation and histopathology''' should be performed on the main site of replication which will vary with disease and virus species as discussed in clinical signs. '''Intranuclear inclusion bodies''' are common and suggestive but not specific to adenoviruses. The virus can be innoculated into cell cultures and easily identified by '''electron microscopy''' or '''staining with fluorescent antisera'''. Serum neutralisation can be used to determine individual species using standard antisera.

Antigen can be detected using '''double immunodiffusion''' which is specific to serogroup.

Antigen can be detected using '''double immunodiffusion''' which is specific to serogroup.

'''EDS virus''' is unusual in that it '''haemagglutinates chicken and duck erythrocytes''' and this provides a diagnostic testing method: haemagglutinin inhibition.  

'''EDS virus''' is unusual in that it '''haemagglutinates chicken and duck erythrocytes''' and this provides a diagnostic testing method: [[Agglutination|haemagglutinin inhibition]].  

Changes seen at '''necropsy''' vary widely with viral species. QB virus causes accumulation of haemorrhagic mucus in the respiratory tract and nasal-ocular discharge. Lung consolidation may be a feature where disease is severe. Basophilic Intranuclear inclusion bodies are also common in the epithelia of the respiratory tract. In IBH, the liver is enlarged, friable and discoloured pale yellow-brown with surface haemorrhage, histological necrosis and again, Intranuclear inclusion bodies which may be eosinophilic or basophilic. HE virus causes dark red/black discolouration of intestines which are often blood filled. <ref>Pierson, F. W., Domermuth, C. H., Gross, W. B (1998) '''Hemorrhagic enteritis of turkeys and marble spleen disease of pheasants'''. In: Swayne, D. E., Glisson, J. R., Jackwood, M. W., Pearson, J. E., Reed, W. M. eds. A Laboratory Manual for the Isolation and Identification of Avian Pathogens (4th ed)''Kennett Square, Pennsylvania, USA: American Association of Avian Pathologists, University of Pennsylvania'',106-110</ref> Enlargement of the spleen is a feature of serogroup 2 viruses at post-mortem, with a mottled and friable appearance and congestion of the lungs and liver. The white pulp of the spleen is hyperplastic histologically and intranuclear inclusion bodies form islands within the tissue structure. The characteristic intranuclear inclusion bodies will be seen in the reproductive tract in infections caused by serogroup 3 viruses.

Changes seen at '''necropsy''' vary widely with viral species. QB virus causes accumulation of haemorrhagic mucus in the respiratory tract and nasal-ocular discharge. Lung consolidation may be a feature where disease is severe. Basophilic intranuclear inclusion bodies are also common in the epithelia of the respiratory tract. In IBH, the liver is enlarged, friable and discoloured pale yellow-brown with surface haemorrhage, histological necrosis and again, intranuclear inclusion bodies which may be eosinophilic or basophilic. HE virus causes dark red/black discolouration of intestines which are often blood filled. Enlargement of the spleen is a feature of serogroup 2 viruses at post-mortem, with a mottled and friable appearance and congestion of the lungs and liver. The white pulp of the spleen is hyperplastic histologically and intranuclear inclusion bodies form islands within the tissue structure. The characteristic intranuclear inclusion bodies will be seen in the reproductive tract in infections caused by serogroup 3 viruses.

==Treatment and Control==

==Treatment and Control==

==References==

==References==

Animal Health & Production Compendium, '''Avian adenoviruses datasheet''', accessed 20/06/2011 @ http://www.cabi.org/ahpc/

 

Animal Health & Production Compendium, '''Avian adenovirus infections datasheet''', accessed 20/06/2011 @ http://www.cabi.org/ahpc/

 

 

Smythe, J.A. and McNulty, M.S. (2007) '''Adenoviridae'''. In: '''Poultry Diseases, 6th Edition''' (eds. Pattison, M., McMullin, P., Bradbury, J., Alexander, D.) ''Saunders, Elsevier'', pp 367-382

|datasheet = [http://www.cabi.org/ahpc/Default.aspx?site=160&page=2144&LoadModule=datasheet&CompID=3&dsID=92905 Avian adenoviruses] and [http://www.cabi.org/ahpc/?compid=3&dsid=78845&loadmodule=datasheet&page=2144&site=160 avian adenoviruses infection]