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Study of the entity of rabbit hemorrhagic disease in Korea

韩国兔出血症实体研究

基本信息

批准号：
04044017
负责人：
ITAKURA Chitoshi
金额：
$ 6.53万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

The etiological investigation was made by using the liver homogenate of rabbits infected with rabbit hemorrhagic disease (RHD) virus which originated from Korea. A RHD virus was purified by CsCl density gradient centrifugation from the liver homogenate. The viral particles were 35 to 40 nm in diameter, with surface projections, and had a single major polypeptide of 63 KDa.This purified virus was very high-virulent, and caused acute deaths in adult rabbits 20 to 96 hours after intramuscular injection or contact infection. The dead rabbits showed multiple solitary or focal necroses of hepatocytes, which were regarded as acute viral necrotizing hepatitis.Electron-microscopically, many virus particles were detected in the cytoplasm of degenerated and necrotic hepatocytes. The hepatocytes were damaged directly by viruses. The etiological virus of RHD was identified as a calicivirus from the morphology and replication pattern.Immunohistochemically, RHD virus antigen was detected in degenerative and necrotic hepatocytes of the liver tissue, suggesting that it replicated in these cells. RHD was diagnosed easily and clearly by using the this method.It is known that RHD has never occurred in young rabbits less than two months old in Korea. This was also confirmed experimentally by the present investigation. This unsusceptibility to RHD virus in young rabbits might have relation with the hepatocytic receptors to it.Nervous signs have occurred frequently in Korean RHD. We studied the central nervous system of RHD cases occurring in Korea. As a result, granulomatous encephalitis due to Encephali-tozoon cuniculi was found in them. Therefore, the signs were attributable to encephalitozoonosis and had no relationship with RHD.Recently, RHD in Korea decreases in the incidence. It was considered that this is attributable to a decrease of rabbit population and the development of natural immuninization to RHD virus.

用韩国兔出血症病毒(RHD)感染兔的肝组织匀浆进行病原学研究。用氯化铯密度梯度离心法从肝匀浆中分离纯化出一株RHD病毒。病毒颗粒直径为35~40 nm，表面有突起，具有63 kDa的单一主要多肽。纯化的病毒具有很高的毒力，在肌肉注射或接触感染20~96小时后可引起成年兔的急性死亡。死兔肝细胞呈多个孤立或灶性坏死，为急性病毒性坏死性肝炎，光镜下可见变性、坏死性肝细胞胞浆内可见大量病毒颗粒。病毒直接损伤肝细胞。RHD的病原病毒从形态和复制模式上被鉴定为杯状病毒，免疫组织化学在肝组织变性和坏死的肝细胞中检测到RHD病毒抗原，表明RHD病毒在这些细胞中复制。用该方法可以方便、明确地诊断风湿性心脏病。据了解，韩国从未发生过小于2个月大的幼兔风湿性心脏病。目前的调查也从实验上证实了这一点。幼兔对RHD病毒的这种不敏感性可能与其肝细胞受体有关。我们研究了发生在韩国的RHD病例的中枢神经系统。结果发现由鼠脑钩端螺旋体引起的肉芽肿性脑炎。因此，这些症状可归因于脑孢子虫病，与风湿性心脏病无关。最近，风湿性心脏病在韩国的发病率有所下降。认为这是由于兔数量的减少和对RHD病毒的自然免疫的发展所致。