SUMMARY Infectious bursal disease (IBD) is an immunosuppressive disease of poultry causing great economic losses to the poultry industry. The disease is caused by infectious bursal disease virus (IBDV) and is characterised by bursal lesions, atrophy and immunosuppression. The causal virus targets B lymphocytes and is transmitted mainly by faecal-oral routes through ingestion of contaminated feed and water. Based on virus neutralisation, two serotypes of IBDV have been identified (serotypes 1 and 2), with serotype 1 considered to be virulent. Acute clinical outbreaks of classical IBDV are characterised by sudden onset, high morbidity, spiking and mortality curves with a rapid recovery time of about five to seven days, after clinical signs appear. Mortality rates vary within serotype 1 IBDV strains, ranging from no mortality by the variant strains, about 20% mortality with classical strains and over 50% mortality by very virulent strains. Post-mortem lesions are commonly, but not exclusively, reported in the bursa of Fabricius (BF) observed as haemorrhages, swelling and atrophy. The disease is diagnosed by isolation and characterisation, serology, including agar gel precipitation test (AGPT), enzyme linked immunosorbent assay (ELISA), and molecular techniques, such as reverse transcription polymerase chain reaction (RT-PCR). No effective treatment has been reported for IBD; it can be prevented by vaccination and implementation of strict biosecurity measures.

中文翻译：

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传染性法氏囊病：传播、发病机制、病理学和控制 - 概述

概述传染性法氏囊病（IBD）是一种家禽的免疫抑制性疾病，给家禽业造成巨大的经济损失。该病由传染性法氏囊病病毒（IBDV）引起，以法氏囊病变、萎缩和免疫抑制为特征。致病病毒以 B 淋巴细胞为目标，主要通过粪口途径通过摄入受污染的饲料和水传播。根据病毒中和作用，已鉴定出两种 IBDV 血清型（血清型 1 和 2），其中血清型 1 被认为具有毒性。经典 IBDV 的急性临床暴发的特点是突然发作、高发病率、峰值和死亡率曲线，在临床症状出现后，快速恢复时间约为 5 至 7 天。血清型 1 IBDV 毒株的死亡率各不相同，从变异毒株无死亡率，经典菌株的死亡率约为 20%，毒性很强的菌株死亡率超过 50%。在法氏囊 (BF) 中观察到的死后损伤通常（但不是唯一）报告为出血、肿胀和萎缩。通过分离和表征、血清学，包括琼脂凝胶沉淀试验 (AGPT)、酶联免疫吸附试验 (ELISA) 和分子技术，如逆转录聚合酶链反应 (RT-PCR) 来诊断该疾病。尚未报告 IBD 的有效治疗方法；可以通过接种疫苗和实施严格的生物安全措施来预防。通过分离和表征、血清学，包括琼脂凝胶沉淀试验 (AGPT)、酶联免疫吸附试验 (ELISA) 和分子技术，如逆转录聚合酶链反应 (RT-PCR) 来诊断该疾病。尚未报告 IBD 的有效治疗方法；可以通过接种疫苗和实施严格的生物安全措施来预防。通过分离和表征、血清学，包括琼脂凝胶沉淀试验 (AGPT)、酶联免疫吸附试验 (ELISA) 和分子技术，如逆转录聚合酶链反应 (RT-PCR) 来诊断该疾病。尚未报告 IBD 的有效治疗方法；可以通过接种疫苗和实施严格的生物安全措施来预防。