Diseases: Infectious Bursal Disease

Introduction

• Also known as Gumboro disease
• An acute, highly contagious disease of young chickens caused by a virus
• Affects the immune system

 

Clinical Signs

Chickens 3 to 6 weeks of age most susceptible to clinical disease

• Soiled vent feathers; whitish or watery diarrhoea
• Anorexia
• Depression
• Chickens look pale, huddle together
• Mortality varies - up to 100% in hypervirulent form

Subclinical disease usually in birds less than 2 weeks old; causes impaired rate of growth and development

 

Post Mortem Lesions

• Haemorrhages in the thigh and pectoral muscles
• Bursa of Fabricius enlarged and moist early in disease
• Bursa of Fabricius small and shrunken later in disease

 

Diagnosis

• Typical signs and lesions are diagnostic
• Histopathology, serology and virus isolation are helpful

 

Sample Collection

• Bursa of Fabricius and spleen for isolation of virus
• Samples of bursa, spleen, thymus and bone marrow for histopathology
• Serum

 

Transmission

• Extremely contagious – spreads by contact with infected birds
• Virus is very resistant  - may survive in the environment up to 4 months in contaminated bedding and sheds, in water, feed and droppings
• Spread on clothing and equipment

 

Treatment

• No specific treatment
• Good feeding and care of the sick birds

 

Prevention and Control

• Vaccines are used in commercial flocks
• Isolate sick chickens