一种新的鸭病(暂名鸭出血性坏死性肝炎)病原学研究初报

The Primary Study of Pathogen of Duck Hemorrhagic-necrotic Hepatitis

【研究目的】分离并初步鉴定鸭出血性坏死性肝炎的病原。【研究方法】番鸭胚尿囊腔接种法分离病原,并通过电镜观察、动物回归、分离毒部分理化生物学特性、核酸节段分析等方法鉴定病原。【研究结果】从临床表现为肝脏不同程度点/斑块状出血和坏死点/灶为主要病变的病死雏番鸭和雏半番鸭肝脾组织中分离到8株病毒。分离毒能致死番鸭胚和鸡胚,胚体充出血、胚肝肿大出血坏死;人工感染1～2日龄雏番鸭、雏半番鸭均能复制出与临床自然发病鸭相同的临床症状和病理变化,并能回收到病毒;分离毒能在番鸭胚成纤维细胞(MDEF)中增殖并产生细胞病变,经电镜观察,病毒在细胞浆中增殖,呈大量散在、成堆和晶格状排列,病毒粒子呈球形、二十面体对称、无囊膜、双层衣壳、直径70nm左右;分离毒不能凝集鸡和鸽红细胞,对乙醚、氯仿、FUDR不敏感;病毒核酸为dsRNA,在SDS-PAGE中具有禽呼肠孤病毒10个RNA片段的特征(L1-3、M1-3和S1-4);应用MDRV特异性引物不能从分离毒中扩增出任何条带。【结论】初步表明分离毒是鸭出血性坏死性肝炎的病原,鉴于分离毒的上述特性,暂将此分离毒归属于呼肠孤病毒科正呼肠孤病毒属新型鸭呼肠孤病毒。

[Research purpose] Isolation and preliminarily identification the pathogen of hemorrhagic-necrotic hepatitis. [Research Method] Using allantoic cavity inoculation in muscory duck embryo to isolate the pathogen. The pathogen has been identified by means of electron microscopic observation, animal regression, some physical chemical and biological characteristics and the analysis of nucleic acid segments. [Results] Eight virus strains were isolated from the liver and spleen of the dead young muscovy ducks and mule duck characterized with symptoms of different degree dot/spot haemorrhage and necrosis in the liver. These isolates could caused the muscovy duck- embryo and chick-embryo to die that showed the hemorrhage and necrosis in embryo-livers. 1-2 old-day birds above infected with these isolates had the same character with clinically dead birds and the virus could be isolated from artificial infected birds. These isolates could proliferate in MDEF and result in CPE. The virus could proliferate in the cytoplasm in order of crystals. The viron was shown spherical, ieosahedron, cubic symmetry, no-envelope, with double-layered capsid, about 70nm in diameter by electron microscopy. These isolates had no haemagglutination activity and were not sensitive with chloroform, ether and FUDR. The PAGE analysis of the viral genome revealed that isolates genome were related to avian reovirus （ARV）, composed of ten segments of dsRNA （L1-3, M1-3 and S1-4）. Moreover, the specific band could not be amplified from isolates by specific primers of muscovy duck reovirus （MDRV）. [Conclusion]The study preliminary showed that these isolates was the pathogen of Hemorrhagic-necrotic hepatitis. Above all, these isolates temporarily belong to new-type duck reovirus, Orthoreovirus Reoviridae