THE PATHOGENESIS OF INFECTIOUS AVIAN ENCEPHALOMYELITIS

An association was demonstrated between the development of clinical infectious avian encephalomyelitis (IAE), the persistence and titre of infectious avian encephalomyelitis virus (IAEV) in the brain of the chicken, the duration of detectable viraemia and the age of the chicken at the time of infection with the virus. The older the chicken at the time of infection the milder the disease, the lower the virus titre in the brain and the shorter the period of viraemia. IAEV serum neutralising antibody was produced earlier after infection in older chickens, and its detection was associated with decreasing virus titres in the brain and the cessation of detectable viraemia. Treatment of chickens with testosterone in ova, to inhibit the development of antibody synthesis, prevented the onset of age-associated resistance and testosterone treated birds were as susceptible to clinical IAE as baby chickens. The results suggested that the ability to produce IAEV serum neutralising antibody was an important component of age-associated resistance to IAE.     

THE PATHOGENESIS OF INFECTIOUS AVIAN ENCEPHALOMYELITIS

The age of the chicken at the time of infection with infectious avian encephalomyelitis virus (IAEV) and the route of the administration of the virus had a marked effect on the development of the clinical disease. Chickens given the virus by intramuscular, intraperitoneal and oral routes exhibited a decreased susceptibility to development of clinical disease with increasing age. Irrespective of age, chickens were consistently susceptible to intracerebral inoculation of IAEV. Chickens infected with the virus at 1-, 7- and 14-days of age developed lower neutralising antibody titres to IAEV than chickens infected at 21 and 28 days. A relationship between the ability to produce specific neutralising antibody to IAEV and susceptibility to the development of clinical disease is discussed.     

THE PATHOGENESIS OF INFECTIOUS AVIAN ENCEPHALOMYELITIS

Normal chickens given infectious avian encephalomyelitis virus (IAEV) orally at 1, 7 or 14 days of age developed infectious avian encephalomyelitis (IAE), whereas those dosed with the virus at 21, 28 and 35 days of age did not. Chickens in all of these age groups that had been treated with cyclophosphamide or testosterone developed clinical IAE. Intraperitoneal inoculation of IAEV immunoglobulin at the time of dosing with the virus, or 48 hours later, protected normal and immunosuppressed chickens against the onset of clinical IAE. The titre of IAEV serum neutralising antibody was found to be lower in normal chickens given the virus at 1, 7 and 14 days of age in older chickens. These results suggest a significant role for the humoral immune system in the pathogenesis of IAE and in the development of immunity to the disease.     

THE IMMUNISATION OF CHICKENS AGAINST INFECTIOUS AVIAN ENCEPHALOMYELITIS

An immune response was induced in chickens vaccinated with the NSW-1 virus by the intramuscular, eye drop, wing web or oral methods. The oral procedure was the most sensitive in inducing an immune response with the lowest dose of virus. The wing web method was the least sensitive. Clinical IAE developed in 1 chicken following intramuscular vaccination. The virus was recovered from the faeces of chickens vaccinated orally with 700 CID50 of the virus from the third to the tenth day after vaccination.     

鸡传染性支气管炎病理形态学及发病机理的研究

１５０只１８日龄雏鸡随机分为两组，试验组９０只接种传染性支气管炎病毒（ＩＢＶ－Ｍ４１）后３５天内分３０批依次于不同时间扑杀，作组织病理学、超微结构及病毒抗原位检查，对照组６０只作相同的检查。结果表明，ＩＢＶ攻击的靶器官是气管，气管的病变表现为粘膜上皮细胞的损伤和脱、残留的在皮细胞增殖形成复层上皮、粘膜固有层及粘膜下层大量淋巴细胞浸润及粘膜逐渐恢复的相互连续的病理过程。肺脏初级、次级支气管也有类似的     

鸡传染性支气管炎病毒（IBV）的血清学分型研究

本文动用气管环血清中和试验对１２个ＩＢＶ毒株进行了血清研究。以气管环纤毛运动为指示系统，以能中和２．０ｌｏｇ１０ＣＤ５０同源病毒血清效价为１个抗体单位，含２０个抗体单位的血清与等量病毒作用测定血清对纤毛运动保护百分率，以欧氏距离数字分类分型，并用ＳＰＳＳ软件聚类分型分析。     

鸡腺胃型传染性支气管炎（综述）

1996年9月份以来，中国青岛及附近地区养鸡场20－90日龄蛋用育成鸡连续发生了一种以流泪，肿眼，伴有呼吸道症状，极度消瘦，拉稀，死亡为特征的一种新的呼吸道传染病。主要剖检表现为腺胃肿大如球状，腺胃壁增厚，腺胃粘膜出血溃疡，腺胃乳头平整融合，轮廓不清，可挤出脓性分泌物的腺胃炎症变化。本病病原通过鸡胚盲传5－6代，电镜观察到典型的冠状病毒。因为引起腺胃的特征性的病理变化，因此将此病暂定名为腺胃型传染性支气管炎。我们青岛地区鸡场的分离株定为QXIBV株。本篇从病原学、临床症状、发病机理和流行病学、免疫学、实验诊断和疾病控制方面进行综合论述。本病与肠型传支在理化特性、形态和毒力上相似，可能是同一种新的IBV变异株。