| 英文描述 | An acute contagious viral disease of susceptible young chickens (3-6 weeks old) characterized by mild respiratory symptoms, white watery droppings, severe depression, and death. The Infectious Bursal Disease (IBD) virus is a member of the birnavirus genus, family BIRNAVIRIDAE, and damages all lymphocytes, especially cells of bursal origin. In the early stages,the cloacal bursa is swollen to 3 times normal, gelatinous to yellowish, even hemorrhagic in appearance. Bursal striations and blood poisoning occur in the critical stage. Loss from IBD alone is relatively low, however, losses due to lowered immunal protection from secondary conditions can reach 40%. Diagnosis is by flock history, necropsy, serology (virus neutralization, AGP, and ELISA). Confirmation is by viral isolation from spleen and bursa. |
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