Crerar S K, Cross G M
Department of Animal Health, University of Sydney, Camden, New South Wales.
Aust Vet J. 1994 Dec;71(12):410-3. doi: 10.1111/j.1751-0813.1994.tb00956.x.
The epidemiological and clinical features of big liver and spleen disease (BLS) in flocks on two broiler breeder farms were investigated by serology and gross pathology. The most common necropsy findings on farm 1 were splenomegaly and hepatomegaly, with kidney enlargement in some birds. In one flock (farm 1), a decline in egg production began at 40 weeks of age and lasted for 9 weeks. Seroconversion to BLS antigen was first detected at 45 weeks (3.1% of birds) and increased to 72% at 50 weeks, which coincided with clinical recovery in the flock. Antigen was detected before antibody at 44 weeks and persisted at low incidence (< 15%). Farm egg production statistics and serology indicated that the disease affected all flocks on the farm. In three of eight flocks, seroconversion was detected in birds before peak production. The birds in the remaining sheds did not seroconvert or become sick until after peak production. On the second farm, sampling began within a flock already experiencing BLS. Clinical signs and pathology were similar to those seen in flocks on farm 1. However, the lesions that were seen in the pancreas in 15% of birds have not been reported previously. BLS antibody was detected in 78%, and circulating antigen in 14%, of sick birds.
通过血清学和大体病理学方法，对两个肉种鸡场鸡群中发生的大肝大脾病（BLS）的流行病学和临床特征进行了调查。在1号农场，最常见的剖检病变为脾肿大和肝肿大，部分鸡只伴有肾肿大。在一个鸡群（1号农场）中，产蛋量在40周龄时开始下降，持续了9周。血清学检测显示，鸡群在45周龄时首次出现针对BLS抗原的血清转化（3.1%的鸡只），到50周龄时上升至72%，此时鸡群临床症状开始恢复。抗原在44周龄时先于抗体被检测到，并以低发生率持续存在（<15%）。农场的产蛋统计和血清学检测表明，该疾病感染了农场的所有鸡群。在8个鸡群中的3个鸡群中，在产蛋高峰前的鸡只中检测到血清转化。其余鸡舍的鸡只在产蛋高峰后才出现血清转化或发病。在第二个农场，对已经感染BLS的一个鸡群进行了采样。临床症状和病理学表现与1号农场的鸡群相似。然而，在15%的鸡只胰腺中发现的病变此前未见报道。在患病鸡只中，78%检测到BLS抗体，14%检测到循环抗原。
