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1.
This study describes the epidemiological features of bovine spongiform encephalopathy (BSE) in Northern Ireland where the first case occurred in November 1988. They were very similar to those observed in Great Britain except that the annual incidence of BSE in 1990 in Northern Ireland, 2.3 confirmed cases per 10,000 adult cows, was approximately one 10th of that in Great Britain. The findings were also consistent with the current hypothesis that affected cattle had been exposed to a scrapie-like agent via cattle feedstuffs containing ruminant-derived protein. However, a preliminary investigation of the potential sources of infection for cattle in Northern Ireland did not provide any conclusive evidence.  相似文献   

2.
The first case of bovine spongiform encephalopathy (BSE) in Switzerland was diagnosed in November 1990. BSE is--in particular considering its eradication--different from many other livestock diseases. Strict disease control measures were taken from the very beginning by the Swiss authorities in order to protect public as well as animal health. In addition, BSE has stimulated enormous media interest and public concern. The occurrence of the born after the ban (BAB) cases, increasing questions about the zoonotic potential of the disease and trade restrictions against Switzerland led to the "BSE-crisis". In 1999, Switzerland internationally took a leading role in the surveillance of BSE by active investigation of targeted risk population.  相似文献   

3.
Feline spongiform encephalopathy (FSE), a transmissible spongiform encephalopathy or prion disease of cats, first reported in Great Britain in 1990, is believed to result from the consumption of food contaminated by the agent of bovine spongiform encephalopathy (BSE). The accumulation of PrP in non-neural tissues of cats diagnosed as suffering from FSE was investigated by immunohistochemistry. In the majority of the cats no disease-specific PrP was detected in lymphoid tissues. Small amounts of PrP were detected in the spleen of only two of 13 samples examined, in Peyer's patches of one of the two cases for which suitable material was available, but in the myenteric plexus of all four cats in which sections of intestine were examined. In addition PrP immunostaining was found in the kidney of all the cats with FSE whose kidneys were examined.  相似文献   

4.
Bovine spongiform encephalopathy (BSE), a transmissible spongiform encephalopathy in cattle, was first described in England by Wells et al. (1987). The infection occurs mainly due to digestion of feedstuffs containing ruminant derived protein in form of meat and bone meal contaminated with a scrapie-like agent (Wilesmith et al. 1991). Later, cases of BSE were diagnosed in the Republic of Ireland, Oman, France, and Switzerland (Marinovic & Senn 1991). This report describes the first case of BSE in Denmark.  相似文献   

5.
Bovine spongiform encephalopathy: epidemiological studies   总被引：20，自引：0，他引：20  
This study, initiated in June 1987, describes the epidemiology of bovine spongiform encephalopathy (BSE), a recently described novel neurological disease of domestic cattle first identified in Great Britain in November 1986. Records suggested that the earliest suspected cases occurred in April 1985. There was variability in the presenting signs and the disease course, but the majority of cases developed behavioural disorders, gait ataxia, paresis and loss of bodyweight; pruritus was not a predominant sign. The form of the epidemic was typical of an extended common source in which all affected animals were index cases. The use of therapeutic or agricultural chemicals on affected farms presented no common factors. Specific genetic analyses eliminated BSE from being exclusively determined by simple mendelian inheritance. Neither was there any evidence that it was introduced into Great Britain by imported cattle or semen. The study supports previous evidence of aetiological similarities between BSE and scrapie of sheep. The findings were consistent with exposure of cattle to a scrapie-like agent, via cattle feedstuffs containing ruminant-derived protein. It is suggested that exposure began in 1981/82 and that the majority of affected animals became infected in calfhood.  相似文献   

6.
This was a spatial analysis of the epidemic of bovine spongiform encephalopathy (BSE) in Great Britain, based on agricultural census data collected between 1986 and 1996 and BSE case data collected up to June 1997. Kernel smoothing techniques were used to plot the distribution of BSE-positive cattle holdings per 100 holdings per square kilometre and the distribution of confirmed BSE cases per 100 head of cattle per square kilometre. In the early stages of the epidemic reported BSE cases were scattered widely throughout Great Britain, with no clearly identifiable focus. By June 1997, a statistically significant cluster of BSE-positive holdings was identifiable in the eastern part of the South west region of England. During the epidemic the highest densities of confirmed BSE cases per 100 cattle per square kilometre occurred in the greater part of the South west region of England and within Dyfed in the south west of Wales. In Wales, a small number of holdings experienced large numbers of confirmed BSE cases. In the South west region of England a large number of holdings experienced small numbers of confirmed cases. By June 1997, the distribution of BSE-positive holdings across Great Britain was largely determined by factors that influenced the amount of recycled infectious material they were exposed to.  相似文献   

7.
Bovine spongiform encephalopathy: epidemiological features 1985 to 1990.   总被引：4，自引：0，他引：4  
Following the identification of bovine spongiform encephalopathy (BSE) in the British cattle population in 1986 epidemiological studies were launched. This paper provides an updated account of the epidemiological features of BSE from 1985, when the first cases, based on clinical histories, occurred, until 1990. The number of cases up to December 1989 represents an annual incidence of 3.9 confirmed cases per 1000 adult animals in Great Britain. Many more dairy herds were affected than beef suckler herds, a difference attributable to the difference in feeding practices between the two herd types. The geographical variation in incidence previously described has persisted with the highest incidence in the south and east of England. Other features of the epidemiology, including the low within-herd incidence, remained unaltered from the earlier findings. The results support the previously suggested hypothesis that the outbreak of BSE was due to the sudden exposure of the cattle population to a scrapie-like agent in 1981/82. There was no evidence of direct transmission between cattle during the period considered.  相似文献   

8.
Clinical, pathological and epidemiological details of scrapie-like encephalopathies are described in an arabian oryx and a greater kudu. Clinical signs included ataxia and loss of condition with a short, progressive clinical course (22 and three days, respectively). Histopathological examination of the brains revealed spongiform encephalopathy characteristic of that observed in scrapie and bovine spongiform encephalopathy (BSE). It seems probable that these cases have a common aetiology with BSE. Scrapie-like spongiform encephalopathies have now been described in five species of exotic artiodactyls in Britain indicating a, hitherto inapparent, wider range of ruminant species as natural hosts for these diseases.  相似文献   

9.
The objectives of this study were first to describe the pattern of the epidemic of bovine spongiform encephalopathy (BSE) in Great Britain in terms of the temporal change in the proportion of all cattle holdings that had experienced at least one confirmed case of BSE to June 30, 1997, and secondly to identify risk factors that influenced the date of onset of a holding's first confirmed BSE case. The analyses were based on the population of British cattle at risk, derived from agricultural census data collected between 1986 and 1996, and the BSE case data collected up to June 30, 1997. The unit of interest was the cattle holding and included all those recorded at least once on annual agricultural censuses conducted between June 30, 1986, and June 30, 1996. The outcome of interest was the date on which clinical signs were recorded in a holding's first confirmed case of BSE, termed the BSE onset date. Univariate and multivariate survival analysis techniques were used to describe the temporal pattern of the epidemic. The BSE epidemic in Great Britain started in November 1986, with the majority of affected holdings having their BSE onset date after February 1992. After adjusting for the effect of the size and type of holding, holdings in the south of England (specifically those in the Eastern, South east and South west regions) had 2.22 to 2.43 (95 per cent confidence interval [CI] 2.07 to 2.58) times as great a monthly hazard of having a BSE index case as holdings in Scotland. After adjusting for the effect of region and type of holding, holdings with more than 53 adult cattle had 5.91 (95 per cent CI 5.62 to 6.21) times as great a monthly hazard of having a BSE index case as holdings with seven to 21 adult cattle. Dairy holdings had 3.06 (95 per cent CI 2.96 to 3.16) times as great a monthly hazard of having a BSE index case as beef suckler holdings. These analyses show that there were different rates of onset in different regions and in holdings of different sizes and types, that the epidemic was propagated most strongly in the south of the country, and that the growth of the epidemic followed essentially the same pattern in each region of the country, with modest temporal lags between them. The control measures imposed in 1988 and 1990 brought the expansion of the epidemic under control, although the rate of progress was slowed by those regions where the effectiveness of the control methods took some time to take full effect.  相似文献   

10.
There were 118 cases of bovine spongiform encephalopathy (BSE) in Belgium before January 1, 2004. Trends in their age at detection were analysed and attempts were made to use this parameter as a predictor of the current status of the BSE epidemic in the country. The following variables were considered: date of birth, breed, date of detection, mode of detection, and the number and age of animals slaughtered and rendered each month. Age at detection as a function of date of birth was a very poor epidemiological indicator. It was concluded that the increasing age of BSE cases when they were detected was due to the depletion of cases, as a result of there being no new infections, and that it is a reliable indicator of a decrease in the epidemic curve in Belgium. By means of a simulation it is shown how age distribution at the time of detection closely follows the epidemic curve and data from Great Britain are used to illustrate the point.  相似文献   

11.
Following the identification of meat and bonemeal as the most likely source of exposure for the occurrence of bovine spongiform encephalopathy (BSE) in Great Britain case-control studies were initiated to investigate this hypothesis. These involved a comparison of the consumption of specific proprietary calf feedstuffs, and whether or not meat and bonemeal had been included, between animals born in 1983-84 in BSE-unaffected herds and confirmed cases of BSE also born in 1983-84. The feeding of proprietary concentrates containing meat and bonemeal was found to be a statistically significant risk factor for the occurrence of BSE. These studies therefore support the initial hypothesis that BSE occurred as a result of exposure to a scrapie-like agent via meat and bonemeal.  相似文献   

12.
Bovine spongiform encephalopathy (BSE) is a transmissible spongiform encephalopathy of cattle, first detected in 1986 in the United Kingdom and subsequently in other countries. It is the most likely cause of variant Creutzfeldt-Jakob disease (vCJD) in humans, but the origin of BSE has not been elucidated so far. This report describes the identification and characterization of two cases of BSE diagnosed in the United States. Case 1 (December 2003) exhibited spongiform changes in the obex area of the brainstem and the presence of the abnormal form of the prion protein, PrP(Sc), in the same brain area, by immunohistochemistry (IHC) and Western blot analysis. Initial suspect diagnosis of BSE for case 2 (November 2004) was made by a rapid ELISA-based BSE test. Case 2 did not exhibit unambiguous spongiform changes in the obex area, but PrP(Sc) was detected by IHC and enrichment Western blot analysis in the obex. Using Western blot analysis, PrP(Sc) from case 1 showed molecular features similar to typical BSE isolates, whereas PrP(Sc) from case 2 revealed an unusual molecular PrP(Sc) pattern: molecular mass of the unglycosylated and monoglycosylated isoform was higher than that of typical BSE isolates and case 2 was strongly labeled with antibody P4, which is consistent with a higher molecular mass. Sequencing of the prion protein gene of both BSE-positive animals revealed that the sequences of both animals were within [corrected] the range of the prion protein gene sequence diversity previously reported for cattle.  相似文献   

13.
This paper reports the results of a case-control study of the bovine spongiform encephalopathy (BSE) cases born in Great Britain after the statutory reinforcement of the ban (BARB) on the feeding of mammalian-derived meat and bone meal on 31 July 1996. A total of 499 suspect clinical cases of BSE, born after 31 July 1996, and reported negative by July 31, 1996 and were compared with the set of 164 confirmed Great BARB cases in Great Britain detected by both passive and active surveillance. Animal-level risk factors (age and type of feed offered) and herd-level risk factors (herd size and type, number of prereinforced feed ban BSE cases born on the holding, the presence of other domestic species and waste management) were obtained for the analysis. BARB cases were 2.56 times (95 per cent CI 1.29 to 5.07) more likely to be exposed to homemix or a combination of homemix and proprietary feeds were 0.59 times (95 per cent CI 0.50 to 0.69) as less likely to be exposed to the unit increases in the number of prereinforced feed ban BSE cases diagnosed on the natal holding. A supplementary spatial analysis of these cases revealed three areas of excess BARB density: Northwest and Southwest of Wales and Northeast of Scotland.  相似文献   

14.
Transmissible spongiform encephalopathies are degenerative disorders affecting the central nervous system (CNS) occurring in a variety of species. The causative agent is thought to be composed of an abnormal form of the host encoded prion protein (PrPC), termed PrPSc. The conformational change of PrPC into PrPSc can occur spontaneously, however, it can also be induced by PrPSc. Prion diseases such as bovine spongiform encephalopathy (BSE), scrapie and variant Creutzfeldt-Jakob-Disease (vCJD) are most likely caused by peripheral uptake of prions. The process by which prions proceed to the CNS following peripheral uptake is referred to as neuroinvasion. Infection with prions is thought to occur in two phases: After ingestion prions first replicate in lymphatic tissue and then gain access to the CNS via peripheral nerves. Studies looking at the biochemical and clinical characteristics of BSE and vCJD demonstrated that BSE is most likely responsible for vCJD in humans.  相似文献   

15.
An important aspect of the bovine spongiform encephalopathy (BSE) epidemic has been an apparent age-dependent risk of infection, with younger cattle being more likely to become infected than older cattle. Our objective was to determine the age-dependent risk of infection of dairy cattle. We first reviewed unpublished data on the feeding patterns of proprietary concentrates for dairy-replacement cattle. These data showed that autumn- and spring-born cattle would receive different feeding patterns of proprietary concentrates, and so age-dependent risk of infection profiles were obtained separately for autumn- and spring-born cattle. We used back-calculation methods to analyse BSE-epidemic data collected in Great Britain between 1984 and 1996.

Dairy cattle were most at risk in the first 6 months of life; adult cattle were at relatively low risk of infection. Between 6 and 24 months of age, risk profiles reflected feeding patterns of proprietary concentrates in each of the autumn- and spring-born cohorts.  相似文献   


16.
Bovine spongiform encephalopathy was a novel spongiform encephalopathy, in an hitherto unaffected species, that had characteristics of a point source epidemic, with an agent that could have been incorporated into a wide variety of feedstuffs and iatrogenically administered to na?ve populations, and there was early evidence that it was not restricted to bovines. It was vital to establish, albeit experimentally, which other species might be affected, and whether the epidemic could be maintained by natural transmission, if the source was removed. In contrast, scrapie has been endemic throughout Great Britain for centuries, is maintained naturally (even if we don't know exactly how) and has a known host range. The principles, process and integration of evidence from different types of studies, however, are similar for both of these transmissible spongiform encephalopathies (TSE) and can be applied to any emerging or suspected spongiform encephalopathy. This review discusses the experimental approaches used to determine TSE transmissibility and infectivity and how they relate to natural disease and control measures.  相似文献   

17.
牛的海绵状脑病（BSE）的爆发让人们意识到要控制传染性海绵状脑病（TSE）的流行来保护人和动物的健康。羊痒病是世界上传播最广的传染性海绵状脑病,为此,不同国家的兽医当局都有针对痒病的根除计划,除了增强对动物的监管外,还要培育对痒病有抗性的羊。笔者主要综述了当前羊痒病的研究进展。  相似文献   

18.
Summary

An update on animal spongiform encephalopathies other than BSE was presented in part I of this article. Part II of this article focuses on bovine spongiform encephalopathy (BSE). The article describes clinical signs, histological and other changes leading to a diagnosis, the differential diagnosis, and the prospects for pre‐clinical diagnosis of this disease. It describes the origin and course of the epidemic in the UK and discusses the question why it is only the UK which has witnessed such a large‐scale epidemic. Predicted to arrive much earlier, the epidemic now finally seems to have passed its peak. The article goes on to discuss the chance of the disease occurring in a country like the Netherlands and the measures taken to prevent and control the disease, should it occur.

The article concludes with a discussion of what has been found with regard to genetic factors, the results of experimental and unintentional artificial transmission of BSE to various species, and possible implications for human health.  相似文献   

19.
Tropical Animal Health and Production - Bovine spongiform encephalopathy (BSE) of the cattle is the outstanding disease among other transmissible spongiform encephalopathy (TSEs). It can be...  相似文献   

20.
In order to identify the management and feeding practices that might have contributed to the occurrence of bovine spongiform encephalopathy (BSE) in Bavaria, Germany, information from 110 dairy farms on which a case of BSE had been reported was compared with information derived from a questionnaire sent to approximately 10,000 Bavarian farms on which no case of BSE had been reported up to February 2003. Representative information was obtained from 4006 dairy farms. The results indicated that in comparison with these control farms a higher proportion of the BSE farms had also kept pigs or poultry, although the difference was not significant, and that a significantly higher proportion of the BSE farms had fed proprietary concentrates and/or milk replacers to their calves.  相似文献   

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