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1.
A scheme to control and eradicate bovine virus diarrhoea (BVD) was initiated in 1994 in the Shetland Islands by local veterinary surgeons and funded by the Shetland Islands Council and Shetland Enterprise Company. Over a 3-year period every bovine animal on the islands was blood-sampled (heparinised) and laboratory tested using MAb-based ELISAs for BVD virus antibody and antigen detection for evidence of disease. A number of BVD virus positive animals (40) were found and culled. A total of 6150 animals were tested from 213 herds and 43% herds were found to be BVD naive. The remaining herds had experienced infection and contained many BVD antibody positive animals. Some repeat sampling of stock in infected herds determined further virus positive animals which were slaughtered and in 1997 the scheme ceased since it appeared that there were no persistent excretors present. The major risk to the Shetland Islands is from bought-in stock, especially animals which are imported in calf. It is vital that all bought-in animals are tested and proven to be free of BVD virus if these animals are in calf, the calves must be tested a birth to determine status. It is strongly advised that only bulls and bulling heifers or cows are bought into Shetland in future, thus, protecting the present stock. Continued surveillance will be required to claim eradication of BVD from Shetland.  相似文献   

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In February 1999, 12 Dutch herds were vaccinated with a live bovine herpesvirus 1 vaccine from which bovine virus diarrhea virus (BVDV) could be isolated. All vaccine batches that were on the Dutch market and that had not yet reached the expiry date were tested for BVDV. In total, seven of 82 batches tested were found positive. Batch numbers TX3607, VB3914, VB3915, VB4046, TW3391, and TV3294 were positive for BVDV type 1, and batch number WG4622 was positive for BVDV type 2. This latter batch induced clinical signs of BVDV in an animal experiment with susceptible animals.  相似文献   

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山东兖州某商品代肉鸡场的 2 0日龄肉鸡开始出现大批死亡 ,剖检发现肝脏、脾脏、肾脏和心脏等主要脏器均出现大小不等的肿瘤结节 ,采用细胞培养和间接荧光抗体试验的方法从这些病料中同时分离到了禽网状内皮组织增生病病毒 (REV)和马立克氏病病毒 (MDV) ,通过组织病理学检查和斑点杂交的方法表明该鸡场的疫病为REV和MDV共感染引起的肿瘤病。这是国内从商品代肉鸡中同时分离到REV和MDV的首次报道  相似文献   

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Persistent bovine virus diarrhoea virus infection in a bull   总被引:2,自引:0,他引:2  
Investigation of a sight defect in a pedigree bull, born as a result of artificial insemination and ovum transplantation, led to the finding that the animal was persistently infected with bovine virus diarrhoea virus. Virus was cultured from blood and from nasal and ocular swabs and was present in semen in high titre. At necropsy, virus was cultured from a wide range of tissues. The pathological findings are described and discussed as are the potential hazards of such infections.  相似文献   

9.
广西牛羊赤羽病和蓝舌病流行病学调查   总被引:1,自引:0,他引:1  
为了解赤羽病病毒(AKAV)和蓝舌病病毒(BTV)2种虫媒病毒(Arbovirus)在广西的流行与分布情况,本研究对采集自2010年~2011年广西11市的706份牛、羊血清样品进行检测,共检测出AKAV抗体阳性样品382份,总阳性率为54.11%.其中山羊血清82份,阳性率为28.37%(82/289);牛血清300份,阳性率为71.94%(300/417).BTV抗体阳性样品279份,总阳性率为39.52%.其中山羊血清95份,阳性率为32.87%(95/289),牛血清样品184份,阳性率44.12%(184/417).同时检测出2种虫媒病毒抗体185份,占样品总数的26.20%.本研究结果表明2种虫媒病毒在广西广泛流行,并首次证明广西存在AKAV的感染.  相似文献   

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狂犬病毒中和试验的病毒回归试验表明,病毒攻毒液的实际剂量与理论剂量不完全一致.建议在新版<中华人民共和国兽用生物制品质量标准>中增加对病毒攻毒实际剂量范围的规定,以使结果的判定更为合理.  相似文献   

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Groups of ferrets were inoculated intraperitoneally with cell lysates or equivalent doses of whole cells from 9 different cell lines persistently infected with canine distemper virus. Viral persistence in these cell lines was characterized by noncytolytic infection and restricted release of cell-free infectious virus. In vivo replication competency of the various viruses in ferrets ranged from nil to virulent and did not correlate with in vitro titers of inocula. Ferret virulence (cell lysates only) for one cell line (CCL64-RCDV) was associated with morphologic absence of virion assembly, failure to interfere with lytic virus replication after superinfection, and in vitro infectivity restricted to canine macrophage-like tumor cells. Virion protein production in the CCL64-RCDV virulent inoculum and in the CCL64-Ly avirulent inoculum was evaluated by use of the immunoblot technique. All major virion proteins were produced by infected cells. Virulence was not associated with obvious changes in electrophoretic mobility of virion proteins when profiles of ferret-virulent CCL64-RCDV were compared with those of avirulent CCL64-Ly.  相似文献   

12.
Regulation of foreign gene in fowlpox virus by a vaccinia virus promoter   总被引:1,自引:0,他引:1  
A vaccinia virus promoter was evaluated for regulation of a foreign gene in fowlpox virus by a transient expression assay. Fowlpox virus-infected quail cells, transfected with plasmid DNA containing chloramphenicol acetyltransferase (CAT) gene ligated to a vaccinia virus promoter, expressed CAT activity. No CAT activity was detected either in uninfected cells or fowlpox virus-infected cells. These results indicated that a heterologous vaccinia virus promoter can regulate expression of a foreign gene in fowlpox virus.  相似文献   

13.
The safety of three attenuated virus vaccines of proven efficacy against duck virus hepatitis was assessed by controlled laboratory studies which involved the serial transmission of the virus through groups of two-day-old ducklings known to be susceptible to the disease. Each vaccine was initially derived from a different source. Enhancement of virulence which resulted in deaths from the disease in test groups of ducklings occurred in each instance.  相似文献   

14.
Since bovine immunodeficiency virus (BIV), known as bovine lentivirus, has been detected in dairy and beef cattle in various countries around the world, a prevalence study of antibodies to BIV and bovine leukemia virus (BLV) was conducted in draught animals in five provinces in Cambodia, where protozoan parasite infections were suspected in some animals. To clarify the status of draught animals including Haryana, Brahman, mixed-breed, local breed cattle and muscle water buffaloes, a total of 544 cattle and 42 buffaloes were tested, and 26.3 and 16.7%, respectively, were found positive for anti-BIV p26 antibodies determined by Western blotting. There were 5.3% positive for anti-BLV antibodies detected by immunodiffusion test among the cattle, but no reactors among buffaloes and no dual infection for both BIV and BLV was determined in this study. Peripheral blood mononuclear cells from BIV-seropositive cattle were found to have BIV-provirus DNA, as detected by polymerase chain reaction and subsequent Southern blot hybridization. This is the first evidence for the presence of BIV and BLV infections in draught animals in tropical countries such as Cambodia. This wide distribution of BIV suggests its association with problems in animal health as reported worldwide, and that a primary BIV infection can predispose death of affected animals by other aggressive pathogens or stresses.  相似文献   

15.
Objective To determine prevalences of feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) infections in ‘healthy’ cats that, through acute misadventure or other circumstance, were presented to veterinary practitioners. Prevalences of FeLV and FIV in this population were compared to those in a population of predominantly sick cats. Design and procedures Serum specimens were obtained over a 2-year period from 200 cats oldeer than 1 year of age presented to veterinary clinics for routine procedures, including cat fight injuries or abscesses, vehicular trauma, neutering, dental scaling, vaccination, grooming or boarding. An additional 894 sera were obtained over approximately the same period from specimens submitted by veterinarians to a private clinical pathology laboratory, mainly from sick cats suspected of having immune dysfunction, but including some sera from healthy cats being screened prior to FeLV vaccination. FIV antibody and FeLV antigen were detected in samples using commercial enzyme immunoassays. Results Amongst 200 ‘healthy’ cats, the prevalence of FeLV infection was 0 to 2%, and the prevalence of FIV was 6.5 to 7.5%, depending on the stringency of the criteria used to define positivity. FIV infection was significantly more prevalent in cats which resided in an inner city environment (P = 0.013). Of the 894 serum specimens submitted to the laboratory by practitioners, 11/761 (1.4%) were FeLV positive, while 148/711 (20.8%) were FIV positive. The prevalence of FIV was significantly higher in these predominantly ‘sick’ cats than in cats seen for routine veterinary procedures (P < 0.00001), while there was no difference in the prevalence of FeLV (P = 0.75) Conclusions The prevalence of FeLV and FIV in healthy cats may have been substantially overestimated in some previous Australian surveys. FeLV infection would appear to be a rare cause of disease in Australian cats. The higher prevalence of FIV positivity in sick as opposed to healthy cats infers that FIV infection contributes to the development of disease.  相似文献   

16.
A serological survey to determine the prevalence of antibodies to bovine virus diarrhoea-mucosal disease (BVD-MD) virus was conducted on 419 bovine serum samples originating from 18 of 20 regions (except Mwanza and Shinyanga) of the Tanzania mainland. The sera were a small proportion of samples collected for the appraisal of immune response to rinderpest vaccination. The survey indicated that the virus is prevalent in cattle populations and approximately 12% of sera tested contained demonstrable neutralising antibodies against BVD-MD virus.  相似文献   

17.
采用细胞培养、间接荧光抗体试验(IFA)、聚合酶链式反应(PCR)和斑点杂交(Dotblot)的方法从我国不同地区发生肿瘤的病料中同时进行MDV和REV的分离和鉴定。在分离到的13株MDV野毒株中,有4株培养物既能在IFA中与REV的单抗反应,又可以用PCR扩增出REV的LTR;另有4株培养物能扩增出REV的LTR,但在IFA中却不与REV的单抗反应。结果表明我国MD肿瘤中存在着REV的共感染,且我国MDV某些野毒株的基因组中有可能已经整合进了REV的LTR序列。  相似文献   

18.
Twenty-four, six month old lambs were assembled into four groups of five animals each and one group of four animals. All groups were inoculated with lymphocytes from a single donor lamb infected with bovine leukemia virus. The inoculum varied from 250 to 250,000 lymphocytes, in tenfold increments. Animals were exposed by intradermal injection in the neck region immediately anterior to the left shoulder joint. All groups were monitored at 0, 3, 7 and 12 weeks after inoculation using the following procedures: a. Syncytia induction assay for detection of bovine leukemia virus in peripheral blood lymphocytes. b. Agar gel immunodiffusion against the gp51 antigen of bovine leukemia virus for the detection of antibovine leukemia virus gp51 antibody. c. Lymphocyte stimulation test for the assessment of cell-mediated immunity using mitogen, nonfractionated bovine leukemia virus antigen, and partially purified bovine lymphoma tumor-associated antigen for the in vitro activation of lymphocytes from bovine leukemia virus-inoculated and sham-inoculated, control animals. d. Routine hematological techniques for the assessment of total leukocyte and lymphocyte counts. The median infectious dose for lymphocytes from the single bovine leukemia virus-infected donor used in this study was determined to be 2000 cells. The syncytia induction assay detected more infected individuals (13/23) at an earlier time than did the agar gel immunodiffusion assay (10/23). Using either serological or virus isolation techniques, infected animals were first detected at three weeks postinoculation in the group receiving the high-dose inoculum and at seven weeks postinoculation in groups receiving low- or medium-dose inocula.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

19.
A calf persistently infected and immunotolerant to Bovine Virus Diarrhoea virus (BVD virus) was, on purpose, introduced to a herd of heifer calves over 4 months of age that had been reared as recipients for embryo transplantation. All calves were brought in contact with the persistently infected animal. In total, 240 calves were involved in this experiment, 22 of which were serologically negative when introduced. These serologically negative animals developed antibodies against BVD virus within 5 months after introduction. At short distances from the persistently infected BVD virus shedder, negative calves seroconverted within 2 months, but at greater distances the moment of seroconversion was unpredictable. The calves that had undergone a natural infection with BVD virus received embryos after transportation to an allied farm. In total, 14 calves were born after embryo transplantation, all of which were free of BVD virus, in spite of the presence of BVD-virus on the latter farm.  相似文献   

20.
Bluetongue virus in goats   总被引:1,自引:0,他引:1  
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