Acute contagious viral immunosuppressive disease of young chickens.
The desease is characterized by mild respiratory symptoms, white watery droppings, severe depression, vent picking and inflammation followed by atrophy of the bursa of Fabricius.
All chicken are susceptible, but mostly affects chicks up to 12 weeks of age. Occurs world wide.
Transmission is from bird to bird or by contact with contaminated environment.
The virus is shed in exudates and excrements of infected birds. Spreads by air on dust particles within the poultry house. Clinical signs are sudden onset, rapid drop in feed and water consumption.
Mucoid diarrhea with soiling of the vent feathers, feathers are ruffled, chicks are listless, pick at their own vent and sleep with beak resting on the floor. Surviving chicks remain unthrifty and are more susceptible to secondary infections because of imunosuppression.
Diagnosis is confirmed on microscopic tissue study, fluorescent antibody test, virus isolation from bursa, and virus neutralization tests. No specific treatment and antibiotics, sulfonamides and nitrofurans have little or no effect. Vitamin-electrolyte therapy is helpful. Prevention is with attenuated commercial vaccine.