INFECTIOUS BURSAL DISEASE

8^th Semester

Dr. Anil Kumar

Dept. of VCC, BVC

INFECTIOUS BURSAL DISEASE

Synonym : Gumboro disease.

• First time recorded in Gumboro area of U. S. A by Cosgrove and in India by Mohanty etal.
• It is highly contagious disease, between 2 to 6 wks. of age chickens are most susceptible.

ETIOLOGY : Birna virus, Double stranded RNA Virus and have 2 main serotypes i.e. 1 and 2,where 2 produces disease in chicken.

SPREAD :

• Mouth, but also through eye and respiratory tract.
• Litter mites and meal worms(Larvae of various beetles), and mechanical vector(wild birds, human, vermin) play a part in the spread of disease.

SYMPTOMS :

• Severe form is seen in chicks between 3 and 6 wks of age.
• Most earliest symptom is picking of their own vent by some birds.
• Others symptoms vary, depending on the disease producing power of virus, age and maternal antibody level of the chicks.
• They are depression, white diarrhea, soiled vents, anorexia, ruffled feathers, unwillingness to move, trembling, closed eyes, lying down in exhaustion and finally death.
• Mild form may show not any symptoms except poor growth.
• The course of disease in individual birds is short(5to7 days), leading raid death or recovery.

DIAGNOSIS :

• Isolation of virus.
• Serological test.
• P M finding.

VIRUS ISOLATION :

• Infective materials inoculated in bursa fabricious and CAM in 9-11 day old chick embryo leading to death in 3-5 days with mottled liver and kidney and congested lungs.

SEROLOGICAL TEST :

• This include IF, AGPT, VN , ELISA and Electron microscope.
• VN test is a choice method of measuring IBDV antibodies.

PM findings :

• Initially swollen bursa followed by atrophied bursa with hemorrhage in its inner surface is typical of gumboro disease.
• Swollen kidney and pale due to urates.
• Hemorrhages in thigh and breast muscles and also under the skin is third most important lesions of gumboro disease.

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Hemorrhages in thigh muscles.

Enlarged hemorrhagic bursa

Inner surface of hemorrhagic bursa

TREATMENT : No treatment.

PREVENTION and CONTROL :

• Biosecurity.
• Vaccination :
• Immunization of breeding flocks to provide maternal antibodies to their progeny, which protects chicks for 1to 3 wks but boosting immunity with killed vaccines will extend the immunity to 4 or 5 wks.
• To obtained high level of immunity, parents are vaccinated between 4 and 10 wks/ 10-14 wks of age with live vaccine, and again at about 16 wks with killed vaccine.
• In India at present 3 types of vaccines are available. They are :
• Live mild strain( Lukert type) : has low invasiveness and may be neutralized by Mab before it reaches bursa for antibody production.
• Live intermediate(Georgia type) : have good response even in presence of Mab.
• Inactivated vaccines: most effective when chickens are primed with live virus vaccines.

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• Lukert strain intraocular and IBD killed @0.2 ml s.c at 3 to7 days of age.

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• At 14 to 18 days of age IBD intermediate strain @0.1 ml/ bird in drinking water or intraocular in broilers.

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• These above 2 vaccines are sufficient for broilers.
• For commercial layers, intermediate vaccine in drinking water is repeated at 28 to 32 days and again at 42 to 46 days of age.

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For commercial broilers and layers :