摘要
禽流感作为Ⅰ类传染病以及致死率较高的人畜共患病一直受到人们的广泛关注，本项研究应用超微病理学及组织病理学观察手段，从细胞、亚细胞水平对鹅源H5N1 AIV感染7及21日龄SPF雏鸡后机体各器官组织病理学变化进行研究。观察该株禽流感病毒人工感染SPF鸡后器官组织的组织病理学、超微病理学变化。揭示AIV引起的病理学变化规律以及该株禽流感病毒人工感染雏鸡的致病机理。
研究结果表明，主要病理变化出现的时间为1～14天，耐过鸡在感染后21天时基本恢复。雏鸡感染H5N1 AIV后器官呈现广泛的病理损伤，其中，病变较为严重的为心脏、肺脏、脑、肾脏及免疫系统，其次为消化系统。病理组织学变化主要为：心肌细胞变性坏死，并有炎性细胞浸润，呈现实质性心肌炎变化；肺房壁、血管外及呼吸毛细管管壁内可见浆液-纤维素性渗出物以及淋巴细胞、巨噬细胞和嗜酸性粒细胞浸润，呈现间质性肺炎；脑血管充血、炎性细胞浸润，胶质细胞增生，神经元变性、坏死及出现卫星现象和噬神经元现象，表现为非化脓性脑炎：肾脏呈现肾炎变化：法氏囊、胸腺和盲肠扁桃体主要表现为变质性炎或出血性变质性炎；脾脏为急性脾炎；肝脏、胰腺和腺胃主要表现为变质性炎。以上重要实质器官在病毒感染后短时间内发生严重损伤是禽流感造成鸡只迅速大量死亡的重要原因。雏鸡感染AIV也可造成网状纤维系统的显著病变，网状纤维病变以解离为主要特点，其中免疫器官网状纤维在感染后期稍增生。感染雏鸡心脏、肺脏、胸腺、法氏囊、脾脏、大脑、肾脏及肝脏均发生不同程度的超微病理学改变。血管内皮细胞肿胀，管腔内可见红细胞。实质细胞胞核皱缩，染色质聚集或溶解；线粒体肿胀，甚至空泡化；粗面内质网扩张；严重者整个细胞溶解。于被检器官的血管内皮细胞及实质细胞内可见病毒样颗粒。同时发现7日龄雏鸡感染AIV后，病理学变化较21日龄雏鸡严重；死亡率高于21日龄雏鸡；病理变化出现时间提前，持续时间较长。说明感染日龄与发病情况以及发病后的病理变化关系密切，7日龄雏鸡较21日龄雏鸡易感性强。
Avian Influenza as a typeⅠcommunicable disease that causes high fatality rate amongst humanand animals has always received public attentions. This study uses ultramicro-pathematologicalmethod study the pathology of a strain of H5N1 AIV from both cellular and deuto-cellular level.Observations are made on organs and tissues of the inoculated SPF chicken and theirlutramciro-pathematological changes documented, thus showing the pathology of this strain ofH5N1 AIV on inoculated chickens.
Study has shown that major pathological changes appeared from day 1 to day 14 of inoculations.Most of the symptoms disappeared 21 days post inoculation. After inoculation, chicken showedbroad damage to major organs. The most seriously effected ones are the heart, lung, brain, kidneysand the immune system. Effects on digestive systems appeared less. Major pathological damageincludes myocardial cell necrosis, infiltration of inflammatory cell, parenchymatous myocarditis,pulmonary cell, blood vessel, and capillary wall sororities. Lymphocyte, macrophage, eosinophile,and granulocyte infiltration were also present. The pathological histology change mainly displayedparenchymatous myocarditis in the heart of the infecting chickens; interstitial pneumonia in the lung;hemorrhagic alterative inflammation in bursa of fabricius, thymus and cecal tonsil, nephritis inspleen; nonsuppurative encephalitis in cerebrum; acute renal glomerulus nephritis in kidney;alterative inflammation in liver and pancreas; acute catarrhal and hemorrhagic inflammation induodenum.The pathologies describled above causes widespread organ damages in a very shortperiod post inoculation and are the major contributors to the mass mortallity amongst the testsubjects, the ultramicro-pathematological changes to different extent in heart, lung, thymus, bursa offabricius, spleen, cerebrum, kidney and liver of the infected chickens. The changes containedvascular endothelial cell swollen and there were akaryocyte in lumens. Nucelus shrinkaged;heterochromatin concentrated or dissolved; bioblast swelled, even became vacuolization; roughendoplasmic reticulum distended; the integral cell dissolved in severity in parenchyma cell. Therewere virus-like particle in the blood vessel endothelial cells and parenchyma cells of the organs. Thisstudy also showed that 7-day chickens exibited much worse symptons than 21-day chickens. Theirsymptoms showed up earlier, lasted longer, and fatalities are also higher. 7-day chickens were alsomuch more suceptable to H5N1 infection. This demostrated there is strong correlation between thethe age which the test subjected is infected and the patholgies.
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