赤羽病微量血清中和试验方法的建立与应用

以自美国、澳大利亚引进的赤羽病病毒和标准阳性血清,参考国际上常规微量血清中和试验方法,建立了赤羽病(AKV)微量血清中和试验方法。用以对澳大利亚进口的四批绵羊(共1092头)作赤羽病检疫,检出血清阳性反应绵羊70头,有效地防止了国外赤羽病的传人。     

赤羽病间接ELISA检测方法的建立和标化

应用赤羽病病毒(AKV)OBE-1株和牛标准阴阳性血清，以蔗糖密度梯度离心纯化细胞毒为包被抗原，在国内首次建立了检测AKV抗体的间接ELISA方法。该方法与中和试验相关系数0．7614，特异性和重复性良好。应用此方法对南京、上海附近奶牛抽样检测，阳性率分别为26．7％和32．7％。对澳大利亚、加拿大、美国进口牛13600头份进行检测，全部阴性。     

赤羽病琼脂免疫扩散试验诊断方法的研究

应用引自美国和日本的羽病毒和标准阳性血甭,制备了琼脂免疫扩散试验（ＡＧＩＤ）抗原和高免阳性血清,建立了赤羽病ＡＧＩＤ诊断方法。应用此方法对上海、杭州、广州等地的１３８３头牛进行了检疫,ＡＧＩＤ抗体阳性牛７４６头,阳笥率５４．０％,与流行情况相符。同时对从澳大利亚、美国、新西兰和加拿大等国进口的牛、羊、猪血清１６２头份进行了检疫,全部为ＡＧＩＤ抗体阴性。     

我国赤羽病血清学调查报告

赤羽病（Akabanedisease）由布尼病毒局辛波群的ewtus引起牛、羊的一种季节性传染病。成年患牛、羊临床上呈隐性感染，但感染敏感的动物发生流产、早产、死胎、新生儿患AH综合症（关节弯曲（AG）一积水性无脑症（HE））。该病分布于热带和温带地区，我国地理位置正处热带和温带，为此我们应用赤羽病的细胞培养微量中和试验对我国陕西、内蒙、湖南、河北、北京、上海、山东、安徽、吉林、甘肃、江苏、浙江、福建、湖北部分地区送检血清样品进行了赤羽病血清学调查。共检查牛、羊血清2639份，牛阳性率39．18％，羊阳性率12．60％。我国南方…     

边虫补体结合试验微量法的应用

本文应用美国国家实验室常规补体结合试验微量法技术,对两个农场162头牛血清和加拿大、美国、澳大利亚进口牛414头血清进行边虫检查。检出两农场阳性牛5头,疑似牛4头;进口牛中检出疑似牛3头。实验证明,方法敏感特异。报告如下:     

两种ELISA试剂盒与血清中和试验检测牛赤羽病的比较

为比较两种商品化赤羽病抗体ELISA试剂盒的敏感性和特异性,以及ELISA和微量血清中和试验(SNT)的符合率,采用两种ELISA试剂盒和血清中和试验,对690份澳大利亚纯种荷斯坦奶牛血清进行牛赤羽病检测。试验结果显示:法国某公司生产的赤羽病ELISA试剂盒敏感性为93.42%,特异性为81.23%,与SNT间的Kappa值为0.615,为高度符合;日本某公司生产的赤羽病ELISA试剂盒敏感性为39.47%,特异性为96.1%,与SNT间的Kappa值为0.427,为中度符合。比较结果表明:日本某公司生产的试剂盒敏感性较低,容易漏检,不适合用于牛赤羽病初筛;在出入境检疫中,可以采用高通量、半自动化、敏感性高的ELISA方法,对血清样本进行筛选,再采用特异性强的SNT试验进行辅助验证。     

应用微量中和试验进行猪伪狂犬病血清学调查

应用细胞培养微量中和试验（固定病毒稀释血清法）对来自２４个猪场共４２６份血清进行了猪伪狂犬病血清学调查。共检出阳性血清１７１份,血清阳性率达４０．１％,出现血清阳性的猪场有２０个,占所检测猪场的８３．３％,说明伪狂犬病在我省及我国流行相当严重。对其中５０份血清的中和指数（固定血清稀释病毒法）进行了检测,结果中和效价大于１∶２血清的中和指数都在１０２．５以上。     

一种判定微量中和试验的新方法

某些传染病的诊断,如伪狂犬病,猪传染性胃肠炎、赤羽病、牛传染性鼻气管炎、病毒性腹泻——粘膜病等,均需借助细胞做血清——病毒中和试验。目前,特别是微量中和试验的应用更为普遍。判定微量中和试验的结果,一般是借助显微镜观察细胞产生的CPE,这种方法往往夹杂一些主观因素,而且只能逐孔检查,孔与孔之间很易引起错误,造     

应用微量中和试验进行猪伪狂犬病血清学调查

应用细胞培养微量中和试验（固定病毒稀释血清法）对来自２４个猪场共４２６份血清进行了猪伪狂犬病血清学调查,共检出阳性血清１７１份,血清阳性率达４０．１％,出现血清阳性的猪场有２０个,占所检测猪场的８３．３％,说明伪狂犬病在我省及我国流行相当严重,对其中５０份血清中的中和指数（固定血清稀释病毒法）进行了检测,结果中和效价大于１：２血清的中和指数都在１０＾２．５以上。     

赤羽病中山病和茨城病流行病学调查初报

应用引自日本的赤羽病病毒OBE-1株,中山病病毒K47株和茨城病病毒BK13株以及相应的标准阳性血清,建立了这三种病的病毒微量中和试验和琼脂免疫扩散试验诊断方法。应用此方法先后对我国7个省市的牛场进行这三种病的检疫。通过血清检疫、现场临床症状观察和疫病流行规律调查,证实我国目前这三种病都在流行,应引起各方面的重视。     

CONGENITAL BOVINE EPIZOOTIC ARTHROGRYPOSIS AND HYDRANENCEPHALY IN AUSTRALIA: Distribution of Antibodies to Akabane Virus in Australian Cattle after the 1974 Epizootic

At the end of the 1974 epizootic of bovine congenital arthrogryposis and hydranencephaly in south-eastern New South Wales, an Australia-wide serological survey (about 4,000 serums) was made to determine the ditribution of cattle possessing serum neutralising antibodies against Akabane virus. Eighty per cent of the serums from cattle in northern Australia (Western Australia, Northern Territory, and Queensland) were positive. A detailed study in the epizootic area in New South Wales (particularly around Bega) showed that 80 to 100% of serums from cows in herds in this area possessed neutralising antibodies. The animals possessing antibodies extended as far south as Genoa in north-eastern Victoria, and as far west as Darlington Point on the Murrumbidgee River. There were no positive herds along the Murray River, where an outbreak of the mosquito-borne disease Murray Valley encephalitis occurred in 1974. Serums tested from cows in the rest of Victoria, South Australia, south-western Western Australia, and Tasmania were negative. Arthrogrypotic calves born in Tasmania and south-western Western Australia were not associated with the presence of Akabane virus. In Papua New Guinea, serums collected from cattle at Boroka, Lae, and Goroka did not possess neutralising antibodies. The distribution of cattle possessing antibodies in Australia would fit a spread of the virus by Culicoides brevitarsis, a biting midge from which Akabane virus had been isolated on three occasions. The possibility of other vectors, as well as C. brevitarsis, was suggested by the presence of cows possessing antibodies at Alice Springs, where this biting midge has not been found. Possibly most cattle in northern Australia become infected early in life. The epizootics in New South Wales could occur when seasonal conditions allow a southerly extension of virus-infected C. brevitarsis which feed on susceptible pregnant animals. C. brevitarsis also bites sheep, and both neutralising antibodies to Akabane virus and congenitally deformed lambs have been observed in the epizootic area. An understanding of the distribtuion of Akabane virus and C. brevitarsis, a possible Australian vector for bluetongue virus, may prove useful if bluetongue should enter Australia.     

A SURVEY OF ANTIBODY TO AINO VIRUS IN CATTLE AND OTHER SPECIES IN AUSTRALIA

SUMMARY A serological survey of healthy cattle in Australia showed that antibodies to Aino virus were present in serums from cattle in northern Australia and down the east coast as far as central New South Wales in 1975, 1976 and 1977, but occurred with a lower frequency than antibodies to Akabane virus. in contrast to the findings with Akabane virus, no neutralising antibodies to Aino virus were detected in serums from camels, dogs or horses. Antibodies to both viruses were detected in buffaloes and sheep, but not in humans or any of the Australian indigenous species so far tested. All positive serums originated from within the known range of Culicoides brevitarsis.     

A serological survey of Akabane virus infection in cattle and sheep in northwest China

Purpose

Akabane disease characterized mainly by fetal damage is a ruminant disease caused by insect-transmitted Akabane virus infection.

Methods

We investigated Akabane disease using serum neutralization tests in 446 blood samples collected from 187 cattle and 259 sheep of Xinjiang province, northwest China.

Results

(1) The overall prevalence rate of neutralizing antibody was 19.06?% (85/446), (2) the prevalence rates of Akabane disease in cattle and sheep were 20.32?% (38/187) and 18.15?% (47/259), respectively, (3) the disease prevalence rates were not significantly different between cattle and sheep, but significantly different among samples collected from different sampling months, (4) the disease was most prevalent in July when mosquitoes and culicoides were most active, and (5) the disease prevalence rates were significantly different between individuals with abortion experience and without abortion experience (P?<?0.05), suggesting that Akabane virus infection may significantly increase abortion risk in cattle and sheep.

Conclusions

To our knowledge, this is the first report confirming that Akabane virus infection is common in cattle and sheep of Xinjiang province, northwest China and providing useful epidemiological information for cattle and sheep abortion prevention and control.     

Sero-survey on Aino, Akabane, Chuzan, bovine ephemeral fever and Japanese encephalitis virus of cattle and swine in Korea

Vector-borne arboviruses produce mild to severe symptoms in domestic animals. Bovine ephemeral fever (BEF), Akabane, Aino, and Chuzan virus have been primarily attributed to reproductive disorders or febrile diseases in cattle, and Japanese encephalitis virus (JEV) is mainly associated with reproductive failures in swine. We investigated antibody titers from domestic swine against four bovine arboviruses (BEF, Akabane, Aino, and Chuzan virus) and from cattle against JEV in Korea. While the positive rates for Akabane and BEF were 37.4% and 15.7%, the positive incidence of Chuzan and Aino were relatively low, with positive rates of 3.04% and 0.4%, respectively, based on a virus neutralization assay. Antibody titers against more than one virus were also frequently detected in domestic swine. The incidence of JEV was 51.3% among domestic cattle. In addition, one positive case was detected in the thoracic fluids from 35 aborted calves, based on the hemagglutination inhibition test. Our results indicate that swine are susceptible hosts of bovine arboviruses without showing clinical symptoms in a natural environment. Moreover, we confirmed that JEV could be associated with reproductive failure in pregnant cattle, as were other vector-borne bovine arboviruses assessed in this study.     

A sentinel herd system for the study of arbovirus infections in Australia and Papua-New Guinea

The establishment, and development between 1969 and 1978, of a system of sentinel cattle in herds located in many areas of Australia and in Papua New Guinea is described. Though the system was established for the study of the epidemiology of a variety of viruses infecting cattle, the study has been limited since 1974 to arboviruses. By means of serology, it was established that bovine ephemeral fever virus was present in Australia in subclinical form between major epidemics but was not detected in Papua-New Guinea. The development of antibody to bovine ephemeral fever virus in individual cattle before they developed clinical signs in epidemics was clearly demonstrated. The sentinel technique was used to demonstrate that subclinical Akabane virus infection in cattle occurred at the time that virus was present in its suspected vector,Culicoides brevitarsis which had been collected nearby. The epidemiology of other Simbu group viruses, D'Aguilar virus, and bluetongue virus, (serotype 20) was also studied. A limited programme of arbovirus isolation in tissue cultures produced 0.8% of isolates from 2090 of the blood clots which accompanied sentinel herd serum samples.The most valuable aspect of the sentinel herd scheme has been the accumulation of a well documented representative set of serum samples for retrospective serology by the use of newly isolated or imported antigens.     

新疆部分地区牛支原体病的血清学调查

采用双抗原夹心ELISA法对新疆部分地区采集的103份牛血清进行了牛支原体抗体监测。试验显示,从采集的103份牛血清中检出牛支原体阳性血清30份,阳性率为29.1%。结果表明,牛支原体病在调查地存在,且感染率较高。相关人员应引起高度重视,并积极采取防控措施应对牛支原体病的发生和流行。     

Antibodies to Akabane virus in horses,sheep and goats in Japan

High prevalences of neutralizing (NT) antibody to Akabane virus were obtained with horse (72%), sheep (38%) and goat (67%) serum samples collected in Chiba Prefecture, where outbreaks of abortion and congenital deformities caused by Akabane virus occurred among cattle. In these animal sera, titers of hemagglutination-inhibiting (HI) antibody to Akabane virus and of NT antibody were closely correlated.     

Studies on the pathogenesis of bovine ephemeral fever in sentinel cattle. I. Virology and serology

Twenty-two sentinel cattle were observed daily during an outbreak of ephemeral fever on a dairy farm in eastern Australia in the summer of 1981–192. Of the 22 cattle, 9 developed clinical ephemeral fever. None developed sub-clinical infection. The pattern of the epidemic was a single index case followed 10 days later by the main epidemic wave which lasted for 7 days. This wave stopped when there were still 14 uninfected susceptible animals remaining in the sentinel group, and when biting flies were very active. Ten isolations of bovine ephemeral fever virus were made in Aedes albopictus tissue cultures from the blood of 5 clinical cases. One hundred and twelve isolations of CSIRO Village virus and one each of Kimberley and Akabane viruses were also made from various members of the sentinel group. There was serological evidence that infections with Tibrogargan, Tinaroo and Aino viruses also occurred in 6 cattle in the observation period. The 13 cattle undergoing a sub-clinical viraemia with CSIRO Village virus, Tibrogargan, Kimberley, Akabane or Aino viruses at the time of the main outbreak, appeared to be temporarily protected against ephemeral fever. However, 9 of the 11 still remaining in the herd were susceptible in a subsequent outbreak of ephemeral fever 2 years later. Evidence is presented that subclinical infections with other arboviruses may limit an ephemeral fever epidemic by providing temporary protection by interference.