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1.
应用免疫组化PAP法检测了人工感染成年患兔、30～40日龄患兔以及自然感染患兔体内兔出血症病毒（RHDV）抗原的动态分布。结果表明,在成年患兔的肝、肾、脾、胃、十二指肠、睾丸以及幼兔的肝、肾、脾中检出了RHDV抗原;无论在成年或幼龄患兔,RHDV抗原主要位于受侵害细胞胞浆中,少部分位于核中;在成年患兔,RHDV抗原阳性细胞的数量随病程发展而增加,而在幼龄患兔,这种增加趋势不明显。本文还分析了RHDV抗原在患兔体内的动态分布与病变形成之间的关系。 相似文献
2.
本试验旨在鉴定四川金堂某兔场疑似兔出血症病毒2型（RHDV2）感染疫情的病原,并分析病兔的病理组织学变化。利用血凝试验和RT-PCR检测病死兔内脏组织中的病原,取病变组织制作病理切片,观察分析各组织的病理组织学变化,同时应用病兔肝脏悬液感染幼兔,分析该毒株的致病力。血凝试验结果显示,所采集病死兔肝脏样品能凝集人"O"型血红细胞;RT-PCR扩增及测序结果显示,多对引物均能从样品中扩增出RHDV2特异性条带;病理组织学观察结果显示,病兔多脏器严重出血、肿胀,淋巴细胞和中性粒细胞大量浸润,气管黏膜、肝脏、肺脏出血尤为严重;动物试验结果显示,该毒株毒力较强,含毒肝脏悬液能在24 h内迅速致死幼兔。本研究经临床诊断、核酸检测及测序证实了此次疫情确由RHDV2感染引起,动物试验和病理组织学观察表明该毒株毒力较强,可引发脏器严重出血,造成病兔急性死亡,RHDV2的出现提示病毒的跨境传播情况不容乐观,应引起更大的重视。 相似文献
3.
Raquel M Marques Luzia Teixeira Artur P águas Joana C Ribeiro António Costa-e-Silva Paula G Ferreira 《Veterinary research》2014,45(1):14
Rabbit Haemorrhagic Disease (RHD) is caused by a calicivirus (RHDV) that kills 90% of infected adult European rabbits within 3 days. Remarkably, young rabbits are resistant to RHD. We induced immunosuppression in young rabbits by treatment with methylprednisolone acetate (MPA) and challenged the animals with RHDV by intramuscular injection. All of these young rabbits died within 3 days of infection due to fulminant hepatitis, presenting a large number of RHDV-positive dead or apoptotic hepatocytes, and a significant seric increase in cytokines, features that are similar to those of naïve adult rabbits infected by RHDV. We conclude that MPA-induced immunosuppression abrogates the resistance of young rabbits to RHD, indicating that there are differences in the innate immune system between young and adult rabbits that contribute to their distinct resistance/susceptibility to RHDV infection. 相似文献
4.
新型兔出血症病毒(RHDV2)在全球范围流行并已在我国出现,给养兔业带来巨大威胁。为了解RHDV2与经典兔出血症病毒(RHDV)的异同,从病原学、流行病学、临床症状、致病机理、诊断与防控等方面,阐述了两种病原的不同及相关研究的最新进展。对比发现:RHDV2与经典RHDV亲缘关系较远,抗原表位也存在明显差异,属于不同的病毒分支;经典RHDV主要感染成年家兔,而RHDV2对不同品种和年龄的兔均易感;经典RHDV感染常表现为急性症状,而新型RHDV感染以亚急性和慢性病症为主。目前针对RHDV2的检测和疫苗研究还相对滞后。鉴于RHDV2与经典RHDV之间免疫交叉性较弱,免疫预防上存在较大空白,下一步应加大RHDV2毒株结构功能研究,加快疫苗开发,做好可疑病例处置和流行病学研究,及时掌握我国疫情动态。本文为我国兔病毒性出血症的预防与控制提供了参考。 相似文献
5.
Ferreira PG Costa-e-Silva A Monteiro E Oliveira MJ Aguas AP 《Research in veterinary science》2004,76(1):83-94
Young rabbits are naturally resistant to rabbit haemorrhagic disease (RHD) caused by the same calicivirus that kills, within 3 days, nearly all adult animals. We have investigated changes in blood leukocytes, and in the morphology and biochemistry of the liver (the organ where caliciviruses replicate) of young rabbits undergoing benign infection by the RHD virus. Four-week-old rabbits were infected with a calicivirus inoculum having a titre of 2(12) haemagglutination units either sacrificed 18, 24, 48 and 72 h later, or kept for follow-up studies up to 21 days after inoculation. The infection caused an acute and transient decrease in blood heterophils, and sustained enhancement in hepatic transaminases. Inflammatory infiltrates of the liver were seen in all animals after 24 h of infection; they had a predominant midlobular location. Hepatocytes could present different degrees of cell damage, including cell death; these lesions were limited to the liver cells located around the inflammatory infiltrates. Liver transaminases peaked 24-48 h after calicivirus infection; this was the same timing when liver infiltration and hepatocyte damage were more evident. No alterations of other parameters of liver biochemistry were observed. We conclude that calicivirus infection of young rabbits causes a subclinical disorder characterised by an acute and transient decrease in circulating heterophils, and focal liver damage that is expressed by intralobular infiltration by heterophils, initially, and, later on, by mononuclear cells. Our finding of persistence of increased values of liver transaminases suggests chronicity of the infection in young rabbits. We propose that, although resistant to RHD, young rabbits infected by calicivirus may be long-term carriers of the infectious agent and, thus, become a major source of transmission of the virus. 相似文献
6.
7.
Hepatic lesions in young rabbits experimentally infected with rabbit haemorrhagic disease virus 总被引：3，自引：0，他引：3
O. MIKAMI J. H. PARK T. KIMURA K. OCHIAI C. ITAKURA 《Research in veterinary science》1999,66(3):237-242
Twenty young rabbits (eleven 2-week-old and nine 4-week-old) were experimentally infected with rabbit haemorrhagic disease virus (RHDV) to clarify susceptibility. They were killed chronologically up to 96 hours post-inoculation (PI) and examined for lesions. All inoculated rabbits were clinically normal, but grossly minute white or grey spots were detected throughout the liver. Histologically, the lesions consisted of aggregates of lymphocytes, macrophages and heterophils, with or without acidophilic bodies and necrotic hepatocytes. Immunohistochemically, RHDV antigens were found in the degenerated hepatocytes and in macrophages. The cellular aggregates were considered to be a reaction to necrotic hepatocytes infected with RHDV. It was concluded that some hepatocytes are susceptible to RHDV in young rabbits. 相似文献
8.
Ferreira PG Costa-E-Silva A Oliveira MJ Monteiro E Aguas AP 《Veterinary immunology and immunopathology》2005,103(3-4):217-221
Calicivirus infection is lethal for adult rabbits, whereas young rabbits (less than 8-weeks-old) are resistant to the same infectious agent. The virus replicates in the liver and causes a fulminant hepatitis in adult rabbits leading to rabbit haemorrhagic disease (RHD); this is in contrast with the mild and transient hepatitis observed in infected young rabbits. We have used electron microscopy to compare liver leukocyte infiltrates between young (resistant) and adult (susceptible) rabbits, 36-48 h after inoculation of the animals with caliciviruses. In adult rabbits, liver infiltrates were made up mostly of heterophils, and they were located near hepatocytes showing severe cellular damage. In contrast, liver leukocyte infiltrates of RHD-resistant young rabbits were dominated by lymphocytes that depicted membrane contacts with the cell surface of undamaged hepatocytes. We conclude that: (i) the cellular inflammatory response of the liver to calicivirus infection is different in rabbits that are susceptible (adult) or resistant (young) to RHD; (ii) leukocyte infiltration of the adult liver by heterophils is probably directed at the removal of dead hepatocytes, whereas the liver lymphocytic infiltration of young rabbits suggests the expression of viral antigens on the surface of liver cells of the RHD-resistant animals. 相似文献
9.
Prieto JM Fernandez F Alvarez V Espi A García Marín JF Alvarez M Martín JM Parra F 《Research in veterinary science》2000,68(2):181-187
This study evaluated the time course distribution of rabbit haemorrhagic disease virus (RHDV) structural protein VP60 in tissues from experimentally infected rabbits from three different age groups. Viral VP60 antigen could not be detected in tissue samples from animals under four weeks, and only a few hepatocytes (0.01 to 0.2 per cent) were stained in the 6-week-old animals. A 6-week-old rabbit euthanised at 72 hpi showed VP60-labelling in hepatocytes and macrophages close to areas of inflammation. Viral VP60 antigen was detected as early as 12 hpi in a few hepatocytes (0.03 per cent) from adult animals. Within this age group, the extent of hepatocyte labelling considerably increased at 18 (3.0 per cent), 24 (25.5 per cent), 36 (50 per cent) and 48 (60 per cent) hpi. Extrahepatic viral VP60 antigen was also detected at 36 and 48 hpi in spleen macrophages and lymphocytes from adult rabbits. These findings support the hypothesis that the hepatocyte is the only cell type in the liver able to support RHDV replication almost immediately after viral infection. 相似文献
10.
11.
Wang X Qiu L Hao H Zhang W Fu X Zhang H He S Zhang S Du E Yang Z 《Veterinary immunology and immunopathology》2012,145(1-2):277-282
Vaccine antigens for rabbit hemorrhagic disease virus (RHDV) are currently derived from inactivated RHDV obtained from the livers of experimentally infected rabbits or from several recombinant immunogens. However, the application of these vaccine antigens has been restricted because of biosecurity and immunity characteristics. In the current study, a recombinant adenovirus expressing the RHDV capsid protein (VP60) was constructed and the expression of the recombinant protein was identified through western blot analysis using RHDV-positive rabbit sera. Eighteen rabbits were immunized by injection, direct oral instillation, or using bait. They were challenged with RHDV isolate three weeks after boost immunization. In all cases, the rabbits immunized with the recombinant adenovirus developed RHDV-specific antibodies and cell immune response. The rabbits injected with the recombinant adenovirus were completely protected against RHDV challenge. The adenovirus expression system may provide a strategy for the immunization of rabbits, particularly for the control of RHDV in wild rabbits. 相似文献
12.
Rabbit haemorrhagic disease virus (RHDV) and Pasteurella multocida bacteria cause severe losses among rabbit populations. The efficacy of a recently developed bivalent vaccine against pasteurellosis and RHDV was investigated. Doses exceeding 2 haemagglutinating units (HU) of viral antigen were sufficient to protect rabbits against infection with RHDV. The bivalent vaccine appeared to be safe for use in all age groups of rabbits, including pregnant females, even after treatment with 20 times the normal vaccine dose. Rabbits injected with 8 or 4 HU of bivalent vaccine showed high antibody titres against both organisms for 9 months after inoculation. The antibody levels against RHDV in young rabbits at 30 days of age were elevated when they originated from mothers with high antibody titres. The most suitable period for vaccination of offspring appeared to be around 50 days of age. The bivalent vaccine against pasteurellosis and RHDV combined speed and longevity of the immune response. Immune protection against pasteurellosis and RHDV can thus be achieved with only one manipulation. 相似文献
13.
《Research in veterinary science》2007,82(3):362-365
Calicivirus infection causes rabbit haemorrhagic disease (RHD) that kills more than 90% of adult animals, whereas young rabbits are naturally resistant to this viral disease. It has been proposed that the different response of adult and young rabbits to calicivirus infection is due to absence of viral receptors in respiratory and digestive systems of young animals. We have searched for liver disease in 4-week-old rabbits inoculated with a calicivirus suspension by intranasal and oral routes. These young rabbits showed cell damage and mononuclear infiltration of the liver. The hepatic lesions were associated with mild to moderate increase in circulating transaminases. We conclude that the previously reported reduction of viral receptors in the epithelium of respiratory and digestive systems of young rabbits does not inhibit calicivirus from inducing liver disease in these hosts. 相似文献
14.
Calicivirus infection causes rabbit haemorrhagic disease (RHD) that kills more than 90% of adult animals, whereas young rabbits are naturally resistant to this viral disease. It has been proposed that the different response of adult and young rabbits to calicivirus infection is due to absence of viral receptors in respiratory and digestive systems of young animals. We have searched for liver disease in 4-week-old rabbits inoculated with a calicivirus suspension by intranasal and oral routes. These young rabbits showed cell damage and mononuclear infiltration of the liver. The hepatic lesions were associated with mild to moderate increase in circulating transaminases. We conclude that the previously reported reduction of viral receptors in the epithelium of respiratory and digestive systems of young rabbits does not inhibit calicivirus from inducing liver disease in these hosts. 相似文献
15.
Detection of rabbit haemorrhagic disease virus antigen in tissues by immunohistochemistry 总被引：1，自引：0，他引：1
Formalin fixed liver, spleen, kidney, heart, lung, duodenum and appendix tissues from nine rabbits, experimentally infected with rabbit haemorrhagic disease virus (RHDV), were investigated for evidence of RHDV antigen by the direct avidin-biotin peroxidase complex immunohistochemical method. In all the rabbits examined, RHDV antigen was detected in degenerative and necrotic hepatocytes of the liver tissues. The area involved coincided with histopathological lesions on serial liver sections. The RHDV antigen was expressed in the cytoplasm of the hepatocytes, suggesting that RHDV replicated in these cells. RHDV antigen was also detected in the spleen. The results of immunohistochemistry were supported by the demonstration of RHDV protein by Western blot analysis and of RHDV particles by protein A-gold immunoelectron microscopy in the liver homogenate from all the rabbits that were examined. 相似文献
16.
Marchandeau S Le Gall-Reculé G Bertagnoli S Aubineau J Botti G Lavazza A 《Veterinary research》2005,36(1):53-62
The data were recorded during a Rabbit haemorrhagic disease outbreak that occurred in France in 2001 in a wild population of rabbits that we have been monitoring since 2000. These data suggested the existence of non-protective antibodies due to a putative RHDV-like virus. Twenty-one blood and 22 liver samples were taken from the 26 corpses of recently dead rabbits that were found. RHDV was found in all liver samples. A first screening for RHD antibodies, carried out using an ELISA based on the detection of VP60-RHDV antigen, showed that 20 of the rabbits were seropositive. Moreover, we determined antibody titres for 13 of these 20 seropositive samples. All were > or = 1/400. Such titres normally indicate antibody levels sufficient to confer protection to all known RHDV or RHDV-like strains. For 16 samples, we determined whether these rabbits had died of a chronic or an acute form of the disease, by employing monoclonal antibody (Mabs)--based differential ELISA. All had died of an acute form of RHD. Because the antibodies detected by this VP60-ELISA test are known to appear 5-6 days after infection and since acute RHD generally kills the rabbits 2-3 days after infection, we assumed that the detected antibodies must have been present before the exposure to the virus that killed these rabbits. A second detection of antibodies was made with Mabs that are specific for RHDV. The results were negative, showing that the antibodies detected with the VP60 ELISA test were not specific for RHDV. We sequenced a portion of the VP60 gene of viruses isolated in 17 rabbits. All RHDV isolates were very similar to the RHDV strains commonly isolated in France during this period, suggesting that this viral strain was not a putative variant that is not neutralised by antibodies. Therefore we conclude that the detected antibodies were probably due to a RHDV-like virus that induces the production of detectable but non-protective antibodies. 相似文献
17.
The report demonstrates that the induction of apoptosis in peripheral blood granulocytes and lymphocytes of rabbits infected with three non-haemagglutinating RHDV strains (English Rainham, German Frankfurt, and Spanish Asturias) is a crucial determinant of the pathogenesis of rabbit haemorrhagic disease. Apoptosis was measured by flow cytometric detection of caspase activity. These studies demonstrated that the investigated RHDV (rabbit haemorrhagic disease virus) viral strains affected leukocyte apoptosis to varying degrees. Enhanced leukocyte apoptosis was detected between 4 and 36h after infection and was more pronounced in lymphocytes than in granulocytes. The data presented here thus provide a preliminary understanding of the kinetics of apoptosis in leukocytes of rabbits infected with RHDV. 相似文献
18.
Luzia Teixeira Raquel M. Marques Artur P. Águas Paula G. Ferreira 《Research in veterinary science》2011,91(1):164-166
Rabbit Haemorrhagic Disease Virus (RHDV), a member of the Caliciviridae family, is the etiologic agent of Rabbit Haemorrhagic Disease (RHD); this viral disease is highly contagious and kills more than 90% of infected adult rabbits. Research on experimental calicivirus infection uses inocula obtained from livers of rabbits dying from calicivirus infection. This implies that caliciviruses have to be purified from liver homogenates. Current methods to isolate caliciviruses from rabbit livers are time consuming. We propose here a new procedure for fast purification of rabbit caliciviruses from liver homogenates that uses centrifugation through an iodixanol gradient. This method offers in approximately 2 h a sample with a high degree of calicivirus purity, as shown by its biochemical and immunocytochemistry analysis, which is also able to kill adult rabbits from RHD within 48 h of inoculation. 相似文献
19.
Chen SY Chou CC Liu CI Shien JH 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(9):951-958
Rabbit hemorrhagic disease virus (RHDV) induced viral fulminant hepatitis in adult rabbits. We investigated the damage of renal function and electrolyte balance in experimentally infected rabbit by measuring the related serum parameters to elucidate the pathogenesis of RHDV as an index for medical treatment. Nineteen New Zealand White rabbits, ten females and nine males, were each intramuscularly inoculated with 0.5 ml 50% rabbit lethal dose (RLD(50)) rabbit hemorrhagic disease virus. Blood samples were collected at 0 hr post inoculation (HPI) and every 6 hr from 18 HPI repeatedly through 66 HPI. After virus inoculation, serum blood urea nitrogen (BUN), creatinine (CREA) and sodium (Na(+)) were elevated to a highly significant level (p<0.0001), whereas serum potassium (K(+)) was moderately elevated to a significant level (p<0.05). Hypoglycemia developed highly significantly (p<0.0001). Serum chloride ion (Cl(-)) was the only parameter which did not change significantly (p=0.077). No significant sexual difference was observed among these parameters. Renal insufficiency progressed from 36 hr, as indicated by the increases in BUN and CREA; significant changes in electrolytes resulting in the increased osmolality of extracellular fluid that induced flow disturbance which consequently destroy the homeostasis in cells. Therefore, the later impairments in renal function and electrolyte balance might be an important threat for rabbits which might have survived from acute fulminant hepatitis in RHD. 相似文献
20.
为提高猪瘟活疫苗的外源性兔出血症病毒(RHDV)的检测敏感性,进行了RHDV对家兔感染途径的致死性比较试验,以便筛选出具有较高致死性的感染途径。将RHDV通过皮下、静脉两种途径感染家兔,比较了家兔两种感染途径的半数致死量(LD_(50)),同时对1批污染RHDV的脾淋源猪瘟活疫苗采用皮下、静脉两种途径注射家兔进行RHDV检测。结果表明,静脉途径对家兔的LD_(50)是皮下途径的126倍;污染疫苗的检测应用也表明家兔感染的静脉途径比皮下途径更加敏感,提高了猪瘟活疫苗外源性RHDV污染的检出率;RT-PCR证实了注苗死亡家兔的肝脏组织含有RHDV。本试验可为《中国兽药典》的修订提供数据参考。 相似文献