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Also Known As: '''''Gumboro Disease''''' — '''''Infectious Avian Nephrosis''''' — '''''Infectious Bursitis'''''
Caused By: '''''Infectious Bursal Disease Virus'' — ''IBDV''
==Introduction==
==Introduction==
[[File:Gumboro.jpg|thumb|200px|right|Bursa of Fabricius in Acute disease, 5 days after infection and 8 days post infection (left to right). Source - Intervet at [http://www.gumboro.com/]]
[[File:Gumboro.jpg|thumb|200px|right|Bursa of Fabricius in acute disease, 5 days after infection and 8 days post infection (left to right). Source - Intervet at [http://www.gumboro.com/]]
Infectious bursal disease is a '''highly contagious [[Viruses | viral]]''' disease of birds caused by an avibirnavirus.
Infectious bursal disease is a '''highly contagious [[Viruses | viral]]''' disease of birds caused by an avibirnavirus.
The virus can survive in a wide range of environmental conditions, remains viable from pH 2-12 and is activated only in 70⁰C for 30minutes. It is also resistant to some disinfectants.
The virus can survive in a wide range of environmental conditions, remains viable from pH 2-12 and is inactivated only in 70⁰C for 30 minutes. It is also resistant to some disinfectants.
IBDV can '''survive''' in poultry houses for '''122 days''' after removal of infected birds and in contaminated water or feed for 52 days.
IBDV can '''survive''' in poultry houses for '''122 days''' after removal of infected birds and in contaminated water or feed for 52 days.
IBDV can infect chickens, ducks, geese and guineafowl but only '''chickens''' show clinical signs of disease.
IBDV can infect chickens, ducks, geese and guineafowl but only '''chickens''' show clinical signs of disease.
Lethal infection is usually seen in chicks '''3-6 weeks old''' due to IBDV being to restricted to cells at a certain stage of development.
Lethal infection is usually seen in chicks '''3-6 weeks old''' due to IBDV being restricted to cells at a certain stage of development.
==Distribution==
==Distribution==
The virus is present worldwide.
The main route of transmission is '''faecal-oral''' and the virus is shed for up to 2 weeks post-infection in large amounts.
The main route of transmission is '''faecal-oral''' and the virus is shed for up to 2 weeks post-infection in large amounts.
The role of wild birds as a mechanical vector is poorly understood.
The role of wild birds as a mechanical vector is poorly understood. IBDV can also be spread by the [[Nematodes |nematode]] parasite, ''Alphitobius diaperinus''.
IBD is not thought to be zoonotic.
==Clinical Signs==
==Clinical Signs==
One of the main effects of IBDV infection is '''mortality'''. This can be in chicks at 3-6 weeks old or later on as a result of severe '''immunosuppression''' allowing other disease to proliferate, in particular, [[Escherichia coli | ''E. coli'']] and gangrenous dermatitis.
One of the main effects of IBDV infection is '''mortality'''. This can be in chicks at 3-6 weeks old or later on as a result of severe '''immunosuppression''' allowing other disease to proliferate, in particular, [[Escherichia coli |''E. coli'']] and gangrenous dermatitis.
The virulence varies massively and so can disease severity. Initial outbreaks are usually the most severe and recurrent disease is milder with lower mortality.
'''[[Diarrhoea]]''', recumbency, '''dehydration''', neurological signs and ruffling of the feathers form a typical presentation of IBDV.
'''[[Diarrhoea]]''', recumbency, '''dehydration''', neurological signs and ruffling of the feathers form a typical presentation of IBDV.
==Diagnosis==
==Diagnosis==
Acute disease is usually recognised in a flock by '''rapid onset, high morbidity''' ([[Diarrhoea | diarrhoea]]) with a spike in mortality and '''rapid recovery'''. Diagnosis is confirmed by post-mortem or laboratory testing.
Acute disease is usually recognised in a flock by '''rapid onset, high morbidity''' ([[Diarrhoea |diarrhoea]]) with a spike in mortality and '''rapid recovery'''. Diagnosis is confirmed by post-mortem or laboratory testing.
===Post-mortem===
On '''post-mortem examination''', carcasses are '''dehydrated''', often with '''darkened pectoral muscles'''. Many '''petechiae''' may be present in the thigh and pectoral muscle masses.
On '''post-mortem examination''', carcasses are '''dehydrated''', often with '''darkened pectoral muscles'''. Many '''petechiae''' may be present in the thigh and pectoral muscle masses.
Mucus may also be present within the [[Alimentary System Overview - Anatomy & Physiology | intestines]]. In advanced disease, renal changes may be evident due to prolonged dehydration.
Mucus may also be present within the [[Avian Intestines - Anatomy & Physiology|intestines]]. In advanced disease, renal changes may be evident due to prolonged dehydration.
Grey foci may also be present on an enlarged [[Spleen - Anatomy & Physiology | spleen]].
Grey foci may also be present on an enlarged spleen.
The [[Bursa of Fabricius | '''bursa of fabricius''']] will usually initially be '''enlarged, oedematous and haemorrhagic.''' Its colour turns from white to cream and a '''yellow transudate''' covers its serosa early in infection.
The [[Bursa of Fabricius|'''bursa of fabricius''']] will usually initially be '''enlarged, oedematous and haemorrhagic.''' Its colour turns from white to cream and a '''yellow transudate''' covers its serosa early in infection.
From 7-8 days following infection, the [[Bursa of Fabricius | bursa]] '''atrophies''' and becomes approximately '''1/3''' of its original weight.
From 7-8 days following infection, the bursa '''atrophies''' and becomes approximately '''1/3''' of its original weight.
IBDV antigen can be detected in cloacal bursa or splenic samples by '''Agar Gel Precipitation''' or '''Immunofluorescence'''.
===Laboratory Tests===
IBDV antigen can be detected in cloacal bursa or splenic samples by '''Agar Gel Precipitation''' or '''[[Immunofluorescence]]'''.
'''Antibody [[ELISA testing | ELISA]]''' can be used for serological diagnosis within a flock. A mimimum of 30 samples is required.
'''Antibody [[ELISA testing|ELISA]]''' can be used for serological diagnosis within a flock. A mimimum of 30 samples is required.
==Treatment==
==Treatment==
'''Vaccination''' is also usually required. Both live and inactivated forms are available. Timing is difficult due to interference of maternal immunity, but oil adjuvanted vaccines can extend maternal immunity to 5 weeks. Vaccination can cause immunosuppression and a degree of bursal damage.
'''Vaccination''' is also usually required. Both live and inactivated forms are available. Timing is difficult due to interference of maternal immunity, but oil adjuvanted vaccines can extend maternal immunity to 5 weeks. Vaccination can cause immunosuppression and a degree of bursal damage.
{{Learning
{{Learning
|flashcards = [[Infectious Bursal Disease Flashcards]]
|flashcards = [[Infectious Bursal Disease Flashcards]]
}}
}}
==References==
==References==
Animal Health & Production Compendium, '''Infectious Bursal Disease Virus datasheet''', accessed 05/06/2011 @ http://www.cabi.org/ahpc/
Animal Health & Production Compendium, '''Infectious Bursal Disease Virus datasheet''', accessed 05/06/2011 @ http://www.cabi.org/ahpc/
[[Category:To Do - CABI review]]
{{review}}
[[Category:Avian Viruses]]
[[Category:Viral Organisms]]
[[Category:Lymphoreticular and Haemopoietic Diseases - Birds]]
[[Category:CABI Expert Review]]