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{{Podcasts
|link = https://bloomsbury.mediacore.tv/media/turkey-viral-hepatitis
}}
Also Known As: '''''TVH — Turkey Hepatopancreatitis — Turkey Viral Hepatitis Virus — TVHV — THV'''''
==Introduction==
Turkey viral hepatitis (TVH) is caused by a virus of the family '''[[Picornaviridae]]''' but is at present not classified any further.
TVH is a '''highly contagious but generally subclinical''' disease.
==Distribution==
TVH is reported in '''Canada, USA, Italy and the UK.''' Its distribution may be greater than this as monitoring is difficult due to the often subclinical nature of the disease.
Transmission is principally from '''faeces''' and can be direct or indirect. It is possible that vertical transmission also occurs.
==Signalment==
TVH affects '''only turkeys''' (''Meleagris gallopav''). Disease occurs primarily in young, '''<6 weeks old birds.'''
==Clinical Signs==
When clinical disease does develop, it is characterised by '''anorexia, weight loss, depression and sudden deaths'''. As the hepatopathy develops, '''neurological signs''' may also develop.
'''Decreased hatchability''' and a drop in egg production are often also seen.
==Diagnosis==
TVH is characterised by '''multifocal hepatic necrosis consisting of grey lesions that may be depressed''' and up to several mm in diameter +/- accompanying '''pancreatic necrosis''' at post-mortem. When present, pancreatic lesions are '''grey-pink and circular''' and can be very extensive. Vascular congestion and haemorrhage are often seen in fatal cases.
Microscopic changes are similar in both organs: '''vacuolation and mononuclear cell infiltrates''' are seen with '''bile duct proliferation'''. Blood often pools around areas of focal necrosis and necrotic cells are visible scattered among the leucocytes. Proliferating reticuloendothelial cells often form '''giant cells'''.
'''Virus isolation''' is the only other method of diagnosis. It can be achieved using '''liver, pancreas, spleen, kidney or faeces'''. Liver is preferred. Homogenised tissues or filtered faeces are inoculated into embryonated chicken eggs and observed for embryonic death and congestion or yolks are harvested. The virus can only be isolated from tissues and faeces until '''28 days post infection'''.
==Treatment and Control==
'''No specific treatment or control''' measures are available. Minimisation of stress and faecal contamination may help.
{{Learning
|flashcards = [[Turkey Viral Hepatitis Flashcards]]
}}
==References==
Gough, R.E. and McNulty, R.S. (2007) '''Picornaviridae'''. In: '''Poultry Diseases, 6th Edition''' (eds. Pattison, M., McMullin, P., Bradbury, J., Alexander, D.) ''Saunders, Elsevier'', pp 350-358
Guy, J.S. (2008) '''Turkey Viral Hepatitis'''. 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 426-430
{{CABI source
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=60957&loadmodule=datasheet&page=2144&site=160 turkey viral hepatitis] and [http://www.cabi.org/ahpc/?compid=3&dsid=60954&loadmodule=datasheet&page=2144&site=160 turkey viral hepatitis virus]
|date = 3 July 2011
}}
<br><br>
{{Dave Cavanagh
|date = 23 August 2011}}
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[[Category:Picornaviridae]]
[[Category:Avian Viruses]]
[[Category:CABI Expert Review Completed]][[Category:CABI AHPC Pages]]
[[Category:Alimentary Diseases - Birds]] [[Category:Reproductive Diseases - Birds]]