云南省楚雄州牛、羊蓝舌病的血清学调查

蓝舌病是反刍动物的一种病毒性传染病,蓝舌病病毒由昆虫库蠓传播.该病能严重引起绵羊发病死亡,水牛、黄牛、山羊易感性低于绵羊.我国自1979年首次在云南省发现动物蓝舌病以来,先后已在29个省区检出蓝舌病抗体.楚雄州山羊饲养量位居云南省第一位,因此,了解蓝舌病在本州反刍动物中的感染流行情况,对今后制定该病的防制措施意义十分重大,为此目的,笔者对楚雄、双柏、姚安、元谋4县(市)的牛、羊蓝舌病进行了血清学调查.     

血清8型蓝舌病病毒侵入北欧

蓝舌病是由蓝舌病病毒感染引起的、库蠓传播的一种严重威胁绵羊和山羊的传染病，在世界许多地方都有流行。牛是贮存宿主，但通常不发病。已知的蓝舌病病毒分为24个血清型。以前，蓝舌病病毒几乎没有在欧洲出现过，但在1998年以后．陆续有几个血清型从土耳其和中东入侵希腊、意大利、西班牙、葡萄牙以及巴尔干半岛的国家。     

介绍几种新的绵羊传染病

一、蓝舌病(Bluetongue) 绵羊蓝舌病是一种虫媒病毒传染病,以发热,坏疽性口炎和蹄炎为主要特征。苏联称本病为绵羊卡他热。病羊舌部可能变蓝,故有蓝舌病之称。病原蓝舌病病毒属于呼肠孤病毒科的环状病毒属(Orbivirus),能在媒介者库蠓和受感染的畜体内繁殖。脾脏和淋巴结是蓝舌病病毒特异性抗原定位的地方,病毒的复制在淋巴样细胞的胞浆内进     

蓝舌病及其防制研究进展

动物蓝舌病是由库蠓传播，由蓝舌病毒（Bluetongue disease virus,BTV)引起，主要侵害绵羊并可感染其它反刍动物的病毒性传染病。本文综述了蓝舌病的历史与分布、病原特性、监测及诊断技术、流行特征及其疫苗的研究。     

琼脂凝胶扩散试验在我省蓝舌病诊断中的应用

蓝舌病是由库蠓传播、蓝舌病病毒引起的侵害反刍动物的严重传染病。蓝舌病病毒系呼肠孤病毒科环状病毒属的成员,该病毒主要引起山羊、绵羊发病和死亡,牛及其他反刍动物常为隐性感染．但可通过媒介昆虫传播,成为本病的重要传染源。张念祖等（1979）在我省首次发现该病,近年来,英国、法国等欧洲国家先后报道在本国发生该疫情。     

蓝舌病及其防制研究进展

动物蓝舌病是由库蠓传播,由蓝舌病毒(Bluetonguediseasevirus,BTV)引起,主要侵害绵羊并可感染其它反刍动物的病毒性传染病。本文综述了蓝舌病的历史与分布、病原特性、监测及诊断技术、流行特征及其疫苗的研究。     

核酸探针技术在蓝舌病研究中的应用

蓝舌病是由蓝舌病病毒(Bluetongue Virus,BTV)引起反刍动物的一种传染病,是由不同品种的库蠓和其它双翅目昆虫、虱、蝇等传播造成流行,可感染多种家畜和野生动物,但主要感染绵羊,而牛和山羊等其它反     

国内首次报道山羊蓝舌病病理学

国内首次报道山羊蓝舌病病理学动物蓝舌病是经库蠓传播的一种主要侵害绵羊并可感染其他动物的非接触性传染病。蓝舌病病毒（ＢＴＶ）对绵羊的致病性研究较多，对山羊的致病性研究得很少，而且结果也不一样。在新疆动物蓝舌病血清学调查时，作者发现，山羊蓝舌病阳性群中，...     

西藏和四川红原地区牦牛蓝舌病的血清学检测

<正>蓝舌病是由呼肠弧病毒科环状病毒属成员蓝舌病病毒引起的,由库蠓传播的反刍动物的一种烈性传染病,病死率平均为29%。19世纪后期南非就有蓝舌病发生,但直到1905年,Spreull经过系统研究确定蓝舌病这个病名。1943年前,该病仅发生于南非。此后,世界各地都有蓝舌病的报道。自1979年我国云南首次发现绵羊蓝舌病以来,湖北﹑安徽﹑四川等地相继报道该病。     

海南省牛、鹿蓝舌病血清学调查报告

蓝舌病是以(虫库)蠓为传播媒介的反刍类动物的病毒性传染病。本病目前在世界上流行很广,已知有24个血清型,它主要危害绵羊,而其它反刍类动物则呈隐性感染。为了解蓝舌病在海南省的感染情况,我所于1988～1989年进行了以供港水牛为主的血清学调     

Ornithodoros coriaceus (pajaroello tick) as a vector of bluetongue virus

Preliminary studies demonstrated that the argasid tick, Ornithodoros coriaceus Koch, could become infected with bluetongue virus (BTV). Ticks became infected after feeding through artificial membranes on BTV-infected suspensions of cell cultures, chicken embryos, and sheep blood. Ticks also became infected after natural feeding on viremic sheep (BTV serotype 17) and cattle (BTV serotype 11). Virus was recovered from the hemolymph and salivary glands of ticks which had ingested BTV either through an artificial membrane or by natural feeding on a host animal. Ticks infected with BTV serotype 13 were capable of transmitting the virus to a susceptible cow at 42 days after ingestion of virus-infected cultures, thus demonstrating the potential of the tick to serve as a biological vector of BTV.     

Evaluation of bluetongue virus diagnostic tests in free-ranging bighorn sheep

Five bluetongue virus (BTV) diagnostic tests were evaluated for use in free-ranging bighorn sheep. We sampled one bighorn sheep population four times between 1989 and 1995. The tests evaluated included virus isolation (VI), polymerase-chain reaction (PCR), serum neutralization (SN), agar-gel immunodiffusion (AGID), and competitive enzyme-linked immunosorbent assay (c-ELISA). The c-ELISA, AGID and SN tests had high levels of agreement in determining serogroup exposure in bighorn sheep. We used maximum-likelihood algorithms to estimate the parameters of each diagnostic test used. Although the c-ELISA and AGID had high sensitivity and specificity, the SN had perfect specificity but lower apparent sensitivity. Due to the potential of cross-reactions among multiple serotypes, results of the SN must be interpreted with caution when assessing serotype exposure in an area where multiple serotypes are endemic. The PCR assay delineated convalescent antibody titers from more-recent infections, and consequently, was pivotal in distinguishing a different exposure pattern between the bighorn sheep and cattle in an adjacent herd. Based on an increasing seroprevalence (50% to 100%), BTV circulated through this bighorn sheep population between 1989 and 1993. This increase in seroprevalence coincided with a bighorn die-off due to BTV infection in June, 1991. An adjacent cattle herd was sampled in 1995 for comparison. The bighorn sheep and adjacent cattle had different patterns of exposure to BTV between 1994 and 1995. There was no evidence that BTV circulated through the bighorn sheep population from 1994 to 1995. In 1995, seroprevalence to BTV decreased to 72%, none of yearling bighorn was seropositive, and all of the 39 bighorn sheep were PCR-negative. In contrast, all adult cattle were seropositive to BTV by c-ELISA and SN, and 4 of the calves were seropositive; 11 of the 24 cattle were PCR-positive, including all five calves. Overall, the pattern of temporal herd immunity in the bighorn sheep appeared to follow a classic epidemic curve, with the appearance and subsequent disappearance of herd immunity coinciding with the 1991 die-off in this population. As low levels of herd immunity and high proportions of susceptible animals are key factors in the development of epidemics, this population of bighorn sheep may be at increased risk for a BTV epidemic in the future.     

No evidence for involvement of sheep in the epidemiology of cattle virulent epizootic hemorrhagic disease virus

Epizootic hemorrhagic disease virus (EHDV) is an Orbivirus. While not previously considered as an important disease in cattle, several EHDV serotypes (EHDV-6 and 7) have recently been implicated in disease outbreaks. The involvement of sheep in the epidemiology of EHDV is still not understood. In this study we compared the prevalence of antibodies to EHDV and bluetongue virus (BTV) in sheep to their prevalence in cattle after an outbreak of EHDV that occurred in Israel during 2006. Sixty-six sheep and lambs scattered in seven herds were compared to 114 cows and calves scattered in 13 dairy cattle herds, matched to the sheep herds by location. While antibody prevalence to EHDV was high in cattle (35.2% within the outbreak zone) no evidence of exposure to EHDV was found in sheep (p<0.0001). Antibodies to BTV were apparent in both cattle and sheep though in the former it was significantly higher (63.2%, 16.7% respectively, p<0.0001), suggesting higher exposure of cattle to biting Culicoides midges. Taken together, these results imply that sheep have a negligible role in the epidemiology of EHDV.     

Epizootiologic study of bluetongue: virologic and serologic results

Heparinized blood and serum samples were obtained from 1,295 ruminants in herds or flocks with bluetongue virus (BTV) infection in 4 western states. Submissions were from herds or flocks with clinical bluetongue (BT), as well as from animals on premises with no history of BT disease. Insects, including Culicoides variipennis, were collected in areas enzootic for BT disease. Viral isolations were in 10-day-old embryonating chicken eggs that were then adapted to Vero cells for serotyping. Sera were tested from group-specific antibody to BTV by the micro agar gel precipitin (AGP) test. Viral isolations were from cattle (81), sheep (122), goats (9), antelope (2), and C varipennis (5). There were 7 isolates of serotype 120, 114 of serotype 11, 42 of serotype 13, and 56 of serotype 17. In herds or flocks from which BTV was isolated, 51% of cattle, 56% of sheep, 21% of goats, and 52% of antelope had AGP antibodies. Virus was isolated from 43% of the cattle and 23% of the sheep that had no demonstrable evidence of AGP antibodies. Viral isolations were seasonal, occurring from August until December. Approximately 30% of the herds or flocks from which virus was isolated had more than one serotype of virus causing infection.     

Recovery of dual serotypes of bluetongue virus from infected sheep and cattle

Dual serotypes of bluetongue virus (BTV) were recovered from field-collected samples of sheep and cattle blood. Two sheep, each infected with both BTV serotypes 10 and 17, were found in a flock with bluetongue disease associated with these two serotypes. One sheep infected with BTV serotypes 11 and 17 was found in a second flock; it was the only viremic sheep detected and was clinically ill. Dual serotype infections of one beef and two dairy cattle were found in three geographically separate herds; mixtures recovered were of BTV serotypes 10 and 17 and serotypes 11 and 17. Clinical signs of illness were absent in the cattle in two herds, but severe conjuctivitis was seen in several cows in a third herd, including the cow with a dual serotype infection (BTV 11 and 17). Two of the cattle with dual infections had no serological evidence of BTV as determined by the agar gel precipitin test; serum was not available from the other cow with a dual serotype infection. The significance of dual infections and immune tolerance are discussed.     

Bluetongue and epizootic hemorrhagic disease in ruminants in Georgia: survey by serotest and virologic isolation

The frequencies of precipitating antibodies to bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) in domestic ruminants and white-tailed deer (WTD) in Georgia were 36% and 32%, respectively (n = 2,200). The frequencies of seropositivity to BTV and EHDV were high among cattle (47% and 42%, respectively [n = 1,068]) and less so in WTD (36% and 34% [n = 414]). The frequencies among sheep were 34% for BTV and 29% for EHDV (n = 286), whereas among goats, seropositivity was 8% for BTV and 7% for EHDV (n = 433). Serum samples from northeastern Georgia (1 of the 4 regions in the survey) had the highest frequency of precipitating antibodies for BTV (45%) and EHDV (38%). The lowest frequency was in southeastern Georgia, with 29% seropositivity for BTV and 24% seropositivity for EHDV. Of the 175 farms or herds in the serosurvey, 70% included animals that had BTV-precipitating antibodies, and 67% included animals which had EHDV-precipitating antibodies. Seventeen viral isolates were obtained from individual animals on 9 different farms. Fifteen of the isolates were BTV--8 from cattle, 4 from sheep, and 3 from WTD; 8 of them were serotype 11, and 7 were serotype 17. Viral isolates from each of 2 WTD were identified as EHDV serotype 1 and serotype 2. Of the total 17 isolates, 11 were from clinically healthy ruminants, and 6 were from animals with clinical signs of BT or EHD. Five of the viral isolates originated from northeastern Georgia, 7 from the northwestern region, and 5 from the southwestern region; none was obtained from specimens from the southeastern region.     

Serological studies of Australian and Papua New Guinean cattle and Australian sheep for the presence of antibodies against bluetongue group viruses

Following isolation of a virus (CSIRO19) from insects in Australia and its identification as bluetongue virus serotype 20 (BTV20), a nationwide survey of antibodies in cattle and sheep sera was undertaken. Initial studies using the serum neutralization (SN) test showed that the distribution of BTV20 antibodies in cattle was confined to the northern part of Australia. Group-reactive antibody tests (agar gel diffusion precipitin, AGDP, and complement-fixation, CF) showed group-reactive cattle sera south of the BTV20 zone (northern Australia), and southwards from Queensland to New South Wales. Very few group-reactive sheep sera (45 out of 16213) were found and these were of doubtful epidemiological significance. Some of these BTV group-reactive, BTV20-negative, sera were tested in SN tests against BTV1 to 17 and Ibaraki (IBA) virus. The results indicated that BTV1, or a closely related orbivirus, was active in cattle in Queensland, northern Western Australia, and New South Wales, and that antibody to BTV15 was present in some of the cattle sera in northern Western Australia and the Northern Territory. Antibody to IBA virus was present in some cattle sera in Queensland, northern Western Australia and New South Wales. SN antibody titres ?60 were also found to a number of other BTV serotypes in cattle sera in northern Western Australia and Queensland (principally, BTV2 and BTV7). Low level reactions were commonly observed against these and a number of other BTV serotypes, often in the same serum samples. Further, 22% of the group-reactive cattle sera did not react with any of the viruses in the SN tests. Such results were difficult to interpret in terms of known Australian BTV or BTV-related isolates.