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| |species = | | |species = |
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| + | Also Known As: '''''Gumboro Disease''''' — '''''Infectious Avian Nephrosis''''' — '''''Infectious Bursitis''''' |
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− | Also Known As – '''''Gumboro disease''''' – '''''Infectious Avian Nephrosis''''' – '''''Infectious Bursitis'''''
| + | Caused By: '''''Infectious Bursal Disease Virus'' — ''IBDV'' |
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− | Caused By - ''Infectious Bursal Disease Virus'' – ''IBDV''
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| ==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. |
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− | 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. |
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| 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. |
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| 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. |
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− | 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. |
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| ==Distribution== | | ==Distribution== |
− | Worldwide
| + | The virus is present worldwide. |
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| 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. |
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− | 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''. |
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− | IBDV can also be spread by the [[Nematodes | nematode]] parasite, Alphitobius diaperinus.
| + | IBD is not thought to be zoonotic. |
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− | IBD is not thought to be zoonotic.
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| ==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. |
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− | Viral virulence varies massively and thus so can disease severity. Initial outbreaks are usually the most severe and recurrent disease milder with lower mortality.
| + | The virulence varies massively and so can disease severity. Initial outbreaks are usually the most severe and recurrent disease is milder with lower mortality. |
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| '''[[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. |
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| ==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. |
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| + | ===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. |
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− | 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. |
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− | 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. |
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− | 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]]'''. |
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− | '''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. |
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| ==Treatment== | | ==Treatment== |
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| '''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. |
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| {{Learning | | {{Learning |
− | |literature search = [http://www.cabdirect.org/search.html?q=title%3A+%28Infectious+Bursal+Disease%29/ IBD Publications]
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| |flashcards = [[Infectious Bursal Disease Flashcards]] | | |flashcards = [[Infectious Bursal Disease Flashcards]] |
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| ==References== | | ==References== |
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| 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]] | + | |
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| + | {{review}} |
| + | [[Category:Avian Viruses]] |
| + | [[Category:Viral Organisms]] |
| + | [[Category:Lymphoreticular and Haemopoietic Diseases - Birds]] |
| + | [[Category:CABI Expert Review]] |