Causative agent 
- IBD virus, family Birnaviridae
- Two major serotypes, serotype I and II
- Variation in virulence



Differential diagnosis 
- Hemorrhagic syndrome
- Newcastle disease



1. History taking 
- Higher incidence occurs from 2 to 10 weeks of age
- Occasional outbreak but transient
- Vaccination program



2. Clinical examination 
- Declination of general condition
- Whitish to greenish and watery diarrhea



3. Necropsy 
- Edematous swelling and yellowish color change
  with follicular hemorrhage and necrotic foci of the
  bursa of Fabricius
- Petechial hemorrhages in the thigh pectoral muscles
- Atrophy of bursa of Fabricious in chronic case



4. Histopathological obersvation 
- Degeneration and necrosis of lymphoid cells in
- Bursal follicles accompanied by severe edema
- Degeneration and necrosis of lymphoid tissues in
  spleen, thymus and cecal tonsil

5. Antigen detection 
Specimen : bursa of Fabricius
Method    :
                  - AGID test
                  - FA test



6. Virus isolation 
Specimen : bursa of Fabricius, spleen
Method    :
1. lymphoblastoid cell culture (BK₃C₂) inoculation
    and detection by FA test
2. chick embryo inoculation by yolk sac or CAM route
    and observation of edema and congestion with
    mottled necrosis of the liver and kidney



7. Virus identification 
- AGID test
- FA test
- VN test

Control 
- Vaccination with live attenuated and inactivated
  vaccine
- Good sanitation and management