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1.
Established foci of Mycobacterium bovis (the causative agent of bovine tuberculosis [bTB]) in free-ranging wildlife are currently under various stages of management on three continents (Africa, Europe and North America) and in New Zealand. Other, as yet undiagnosed, foci seem likely to exist elsewhere. The complex roles that these wildlife foci play in the ecology of bTB remain among the greatest challenges facing bTB control globally. Conceptually, management of bTB in free-ranging wildlife can be thought of as progressing from the discovery of an outbreak through frequently overlapping stages of epidemiological characterization, initial control, simulation and forecasting, focused control, and verification of eradication. Surveillance in its various forms remains a critical component of assessment throughout. Since the Fourth International M. bovis Conference in 2005, research on management of bTB in free-ranging wildlife has encompassed such areas as the human dimensions of wildlife management, mitigation of bTB risks from wildlife on cattle farms, vaccine biology, and epidemiology, with a major contribution from simulation modeling. In order to advance the actual field management of bTB, however, research must be sufficiently grounded to aid development of practical, affordable and politically defensible management interventions which stand a reasonable chance of being implemented. The current management of two wildlife reservoirs of bTB, brushtail possums (Trichosurus vulpecula) in New Zealand, and white-tailed deer (Odocoileus virginianus) in Michigan, USA, serve as contrasting examples of different wildlife management strategies aimed at achieving a common goal. In New Zealand, the importance of agricultural export markets and the status of the possum as a non-native pest have facilitated direct, aggressive management of the disease reservoir, resulting in considerable progress towards bTB freedom since 1994. In Michigan, the relative importance of the hunting economy and of whitetails as a game animal have made such aggressive culling politically untenable. This has forced reliance upon publicly supported, and implemented, management tools, and so provided impetus to better understand social support for wildlife management policy, its limitations, and ways to employ it in disease control policy development.  相似文献   

2.
OBJECTIVES: To determine historical events leading to establishment of bovine tuberculosis in the white-tailed deer population in the northeastern corner of the lower peninsula (NELP) of Michigan and describe factors relevant to the present outbreak of bovine tuberculosis in Michigan. SAMPLE POPULATION: Cattle and white-tailed deer in Michigan from 1920 to 1990. PROCEDURES: A search of extant historical documents (eg, scientific journals, books, public reports, and correspondence and internal reports from governmental agencies) was conducted. Factors investigated included the number of cattle and prevalence of tuberculosis, deer population and density levels, and changes in regional environments affecting the population and management of cattle and wild deer. RESULTS: High deer numbers and severe winter feed shortages resulting from habitat destruction in the NELP in 1930 contributed to the transmission of tuberculosis from cattle to deer. Starvation increased the susceptibility of deer to infection and modified behavior such that exposure to infected cattle was increased. Relocation of deer resulted in spread of infection to other sites, including locations at which spatial clusters of tuberculosis presently exist. Ribotyping of Mycobacterium bovis from a human patient suggests that the strain of M. bovis presently infecting white-tailed deer in the region is the same strain that affected cattle farms at that time. CONCLUSIONS AND CLINICAL RELEVANCE: Feeding deer to maintain numbers above the normal carrying capacity of the NELP led to deer depending on consumption of livestock feed for survival during winter and increased contact with domestic cattle. This practice should be avoided.  相似文献   

3.
Progress in the development of tuberculosis vaccines for cattle and wildlife   总被引:11,自引:0,他引:11  
Vaccination against bovine tuberculosis is likely to become an important disease control strategy in developing countries, which cannot afford a test and slaughter control programme, or in countries which have a wildlife reservoir of Mycobacterium bovis infection. In the past decade, considerable progress has been made in the development and evaluation of tuberculosis vaccines for cattle and for a range of wildlife maintenance hosts including possums, badgers, deer and African buffaloes. Experimental challenge systems have been established for the different target species and the resulting disease process has mimicked that seen in the field. In cattle, neonatal vaccination with BCG appeared to be more effective than vaccination of 6-month-old calves and in most situations no other vaccine has been shown to be better than BCG. However, prime-boost strategies involving combinations of BCG with a protein or DNA vaccine, to improve on BCG vaccination alone, have produced very encouraging results. Differential diagnostic tests have been developed using mycobacterial antigens that are only present in virulent M. bovis to differentiate between BCG-vaccinated and M. bovis-infected cattle. BCG vaccine has been shown to reduce the spread of tuberculous lesions in a range of wildlife species and a prototype oral bait delivery system has been developed. Prospects for the development of improved vaccines against bovine tuberculosis are promising and vaccination approaches could become very valuable in the control and eradication of bovine tuberculosis.  相似文献   

4.
Surveillance and control activities for bovine tuberculosis (bTB) in free-ranging Michigan white-tailed deer (Odocoileus virginianus) have now been underway for over a decade. Significant progress has been made, lowering apparent prevalence in deer in the core area by >60%, primarily via reduction of deer densities through hunting, and restrictions on public feeding and baiting of deer. These broad strategies of the Michigan Department of Natural Resources (MDNR), implemented with the cooperation of Michigan deer hunters, halved the deer population in the bTB endemic area. However, as hunters see fewer deer, their willingness to sustain aggressive harvests has waned, and public resentment of control measures has grown. During the past four years, apparent prevalence in core area deer has held approximately steady just below 2%. After bottoming out in 2004 at an estimated 10-12 deer/km(2), deer numbers have since rebounded by ~ 30%. Public compliance with baiting and feeding restrictions has been variable. In general, hunters in the core area do not perceive bTB as a problem, in spite of 13 years of MDNR outreach. To date, MDNR has expended more than US$23 million on TB-related activities. Of late, a substantial portion of that funding has been diverted to support other programs which have suffered from budget shortfalls. Livestock herd breakdowns continue to occur sporadically, averaging 3-4 per year 2005 to present. In total, 46 cattle and 4 captive deer herds have been diagnosed bTB positive statewide, the majority yielding only 1 positive animal. Five cattle herds were twice infected, one thrice. Michigan Department of Agriculture (MDA) policy emphasis has shifted towards obtaining producer support for wildlife risk mitigation and farm biosecurity. Funding has proven a limiting factor, with the majority of the US$63 million spent to date devoted to whole herd testing. Nevertheless, some initiatives justify cautious optimism. Promising research to support eventual vaccination of wild deer continues. Some hunters and landowners have begun to recognize the costs of high deer densities and supplemental feeding. A peninsula-wide ban on baiting and feeding was enacted. Some cattle producers, recognizing their precarious circumstances, have begun work to change long-held prevailing opinions among their peers about farm biosecurity. Yet formidable challenges remain, and evidence suggests that eradication of bTB, if it can be achieved, will take decades, and will require greater public and political resolve than has been demonstrated thus far.  相似文献   

5.
Attempts to eradicate tuberculosis from cattle and farmed deer in some countries have been frustrated by the existence of wildlife reservoirs of Mycobacterium bovis infection. Possum control programmes in New Zealand using poisons have shown clearly that the brushtail possum is an important source of infection for cattle and farmed deer, and the sum of evidence strongly suggests that badgers serve as a source of infection for cattle in the UK. Bovine tuberculosis can only be eradicated from these countries by controlling M. bovis infection in both wildlife and domestic animals. The most promising options for control of M. bovis infection in wildlife in the longer term include the development of a tuberculosis vaccine for wildlife and a strategy for biological control of possums. The aim of this review is to address the problems and approaches involved in the control of wildlife tuberculosis from an immunological perspective.  相似文献   

6.
OBJECTIVE: To identify major environmental and farm management factors associated with the occurrence of tuberculosis (TB) on cattle farms in northeastern Michigan. DESIGN: Case-control study. SAMPLE POPULATION: 17 cattle farms with infected cattle and 51 control farms. PROCEDURE: Each case farm (laboratory confirmed diagnosis of Mycobacterium bovis infection) was matched with 2 to 4 control farms (negative whole-herd test results within previous 12 months) on the basis of type of farm (dairy or beef) and location. Cattle farm data were collected from in-person interviews and mailed questionnaires. Wildlife TB data were gathered through state wildlife surveillance. Environmental data were gathered from a satellite image-based geographic information system. Multivariable conditional logistic regression for matched analysis was performed. RESULTS: Major factors associated with increased farm risk of TB were higher TB prevalence among wild deer and cattle farms in the area, herd size, and ponds or creeks in cattle housing areas. Factors associated with reduced farm risk of TB were greater amounts of natural open lands in the surrounding area and reducing deer access to cattle housing areas by housing cattle in barns, barnyards, or feedlots and use of electrified wire or barbed wire for livestock fencing. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that certain environmental and management factors may be associated with risk of TB on cattle farms.  相似文献   

7.
Transmission of bovine tuberculosis (Mycobacterium bovis) among wildlife and livestock has created important risks for conservation and agriculture. Management strategies aimed at controlling TB have typically been top-down, regionally focused, and government-led programs that were at best only partially successful. The purpose of this study was to quantify co-mingling of elk and white-tailed deer (WTD) with cattle at multiple spatial scales (i.e., the regional farm scale and winter cattle feeding area patch) in southwestern Manitoba, Canada, to assess the potential for bovine tuberculosis transmission and identify alternative management strategies. For each spatial scale we quantified use of cattle farms by elk and white-tailed deer. We mailed questionnaires to rural households and then conducted personal interviews with 86 cattle farmers to map the spatial distribution of their cattle winter feeding areas at a fine scale. We deployed Global Positioning System (GPS) collars on 48 wild elk and 16 wild white-tailed deer from 2003 to 2011. Elk were observed on farms by 66% of cattle producers, including 5% and 20% who observed direct and indirect contact, respectively, between elk and cattle. Cattle producers consistently (≈100%) observed white-tailed deer on their farms, including 11% and 47% whom observed direct and indirect contact, respectively, between white-tailed deer and cattle. A higher probability of white-tailed deer–cattle contact at the regional scale occurs on farms that (1) left crop residues specifically for wildlife, (2) had larger cattle herds, (3) used round bale feeders, and (4) were farther away from protected areas. None of the GPS-collared elk locations overlapped with cattle winter feeding areas. In contrast, 21% of GPS-collared white-tailed deer locations overlapped with winter cattle winter feeding areas (22% of these were from male WTD and 78% were from female WTD). White-tailed deer selected cattle winter feeding areas with higher (1) forage crop, (2) grassland/rangeland, and (3) forest cover around the cattle feeding area. Farmers overall expressed strongly negative attitudes toward eradicating the elk population or fencing the park to eradicate TB, but were generally supportive of less invasive and farm-based approaches. Our results suggested that management efforts to prevent TB transmission at the wildlife-agriculture interface can be effectively implemented using a ‘bottom-up’ approach that focuses on practical, farm-based mitigation strategies. This approach can be implemented by individual farm operators, is relatively low cost, and is generally well supported by farmers relative to other more extreme and controversial measures like wildlife eradication.  相似文献   

8.
Tuberculosis (TB) caused by Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex, is an important health problem worldwide. The control of TB through vaccination of wildlife reservoirs may potentially have advantages over other management strategies. The most practical approach to deliver vaccines to wildlife is using oral baits that are stable under field conditions and effective in reaching the target species. Baits were developed in our laboratory to deliver oral vaccines to wild boar piglets. However, these baits were well accepted by other wild species. Therefore, bait consumption by different M. bovis hosts was evaluated herein. The results showed that the baits were well accepted by cattle, feral pigs, and adult red deer whereas small mammals like badgers and possums showed varying bait acceptance. Bait acceptance by different species has the advantage of targeting more than one wildlife reservoir when they coexist in the same area and need to be vaccinated for TB control. However, bait delivery methods such as the use of selective feeders to target the desired species should be developed to avoid bait consumption by other species.  相似文献   

9.
An endemic area of bovine tuberculosis (TB) (Mycobacterium bovis) currently affecting wild white-tailed deer (Odocoileus virginianus) in northern lower Michigan, USA, constitutes the first self-sustaining outbreak of the infection in free-ranging North American cervids. Given this precedent, epidemiologic insights gained from the outbreak afford the opportunity to guide not only current surveillance and intervention but also control efforts for future outbreaks involving wildlife reservoirs. Our specific objectives were to evaluate retrospective data from field surveillance conducted from 1995 to 2000 to determine apparent prevalence, trends in apparent prevalence, and the effects of various factors on the odds of being M. bovis positive.Data were gathered from post-mortem examinations of 62,560 wild deer collected from all 83 Michigan counties. Records of survey method, sex, age, geographic area and infection status as determined by mycobacterial culture were subjected to trend analysis and multivariable logistic regression. Apparent prevalence for the period was 0.54% (336/62,560) statewide. Prevalence varied widely with geographic area, but significantly decreased since 1995 in the core area of the outbreak-which coincided with implementation of control strategies. Significant risk factors were geographic area, sex, age, and the sex-by-age interaction. The survey method by which deer were obtained for testing was not a predictor of infection.Our results to date suggest an outbreak characterized by broad areas of very low prevalence surrounding focal areas where prevalence is sometimes orders-of-magnitude higher (e.g., deer originating from the core area were up to 147 times more likely to be TB positive than deer from other areas). Our results also identify older male deer as most likely to be M. bovis positive (OR=11.3, 95% CI 3.2, 40.3 for bucks > or =5 years vs. does < or =1.5 years)-an observation consistent with the biology and behavior of the species. Synthesizing these results with those of other ongoing investigations, we hypothesize a two-stage model of disease transmission where TB is maintained at very low prevalence in matriarchal groups, with primary dissemination of the disease attributable to the dispersal and movements of bucks (as well as to the large aggregations of animals created by human activities).  相似文献   

10.
The recent discovery of tuberculosis in free-living white-tailed deer in northeastern Michigan underscores the need for increased understanding of the pathogenesis of tuberculosis in wildlife species. To investigate lesion development in white-tailed deer, 32 deer were experimentally infected by intratonsilar instillation of 300 colony-forming units of Mycobacterium bovis. Three deer each were euthanatized and examined at days 15, 28, 42, and 56 after inoculation, and five deer each were euthanatized and examined at days 89, 180, 262, and 328 after inoculation. Microscopic lesions first were seen in the medial retropharyngeal lymph node and lung 28 and 42 days after inoculation, respectively. Lung lesions were present in 12 (38%) of 32 deer, involving 23 lung lobes. Left caudal and right middle and caudal lobes were involved in 17 (74%) of the 23 affected lung lobes. Lesions in the medial retropharyngeal lymph node first appeared as granulomas composed of aggregates of macrophages and Langhans-type giant cells. Some early granulomas contained centrally located neutrophils. As granulomas developed, neutrophils were replaced with a central zone of caseous necrosis that first showed signs of mineralization 42 days after inoculation. Granulomas increased in size as the zone of caseous necrosis expanded. Peripheral fibrosis, first seen at 56 days after inoculation, progressed to only a thin fibrous capsule by 328 days after inoculation. By the termination of the study, the central necrotic core of the granuloma contained abundant liquefied necrotic material and grossly resembled an abscess. Although tuberculous lesions in white-tailed deer follow a developmental pattern similar to that in cattle, fibrosis is less pronounced and the advanced lesions may liquefy, a change seldom reported in cattle. An understanding of lesion development will aid in the identification of the spectrum of disease that may be seen in this important wildlife reservoir of tuberculosis.  相似文献   

11.
Mycobacterium bovis was probably introduced into New Zealand with cattle imported in the early 19th century. A tuberculosis control programme was introduced for cattle in 1945. However, the control of tuberculosis in cattle and deer in New Zealand over the past two decades has been hampered by the presence of an important wildlife reservoir, the Australian brushtail possum (Trichosurus vulpecula). While the importance of this source of infection has been suspected by the Ministry of Agriculture for some time, scientific proof has been lacking until recently. A new control programme is currently being finalized with the following objectives: to reduce the prevalence of herd infection in vector free areas to internationally accepted levels, to prevent the establishment of tuberculous vectors in new areas, to decrease the number and size of existing areas where tuberculous vectors exist, and to encourage land-owners to take action against tuberculosis on their properties and in their herds.  相似文献   

12.
Bovine tuberculosis (TB) is a serious zoonotic disease, which despite a largely successful test and slaughter programme has persisted in cattle herds in parts of the UK. The badger (Meles meles) is widely considered to represent a significant wildlife reservoir for the transmission of Mycobacterium bovis to cattle, and has been the subject of a variety of culling strategies since the mid 1970s. Nevertheless, the incidence of herd breakdowns has continued to rise, and the efficacy of culling is currently the subject of a large-scale field trial. One potential alternative tool for the management of disease in wildlife populations is vaccination. However, the successful development of an effective vaccine and a strategy for its delivery will require careful consideration of the practical constraints imposed by ecological factors. In the current paper, we discuss relevant ecological and epidemiological characteristics of badger populations and practical aspects of vaccine delivery in the field.  相似文献   

13.
Intensification of game management may increase the prevalence of tuberculosis (TB) in wildlife despite eradication programs implemented in cattle herds in the same areas. In this cross-sectional study, we investigated the association between wild game management practices and the presence of tuberculosis in red deer populations in Southwestern Spain. Five hundred and fifty-one animals were examined by necropsy to detect tuberculosis-like lesions in the main lymph nodes. Prevalence, as determined by TB-like lesions, was estimated to be 5.1% of animals, with 77% of TB-like lesions confirmed by PCR. Our results suggest that population density, in addition to factors which promote the local aggregation of animals, is factors associated with increased prevalence of TB in red deer populations. We suggest that management practices including supplementary feeding, fencing, water ponds and interaction with domestic livestock should be revised in order to prevent TB in wild deer both.  相似文献   

14.
U.S. state fish and wildlife agencies have responded to perceived ecological and social threats posed by mute swans by implementing population control strategies. In Michigan, some stakeholder groups have vocally opposed particular control activities. To better understand and characterize key aspects of the underlying media dialogue about mute swan management in Michigan, one factor in the development of public perceptions about wildlife issues, we conducted a qualitative content analysis of Michigan-specific online news articles. Results revealed tensions between stakeholder groups about management priorities were rooted in differing ideas about healthy social and ecological systems, appropriate wildlife behavior, and the acceptability of lethal control (i.e., shooting living birds). Characterizing which stakeholder groups aligned with particular arguments might allow managers to tailor and direct messaging to specific audiences.  相似文献   

15.
牛结核病流行特点及防控措施   总被引:2,自引:0,他引:2  
牛结核病是一种慢性消耗性人兽共患病,是OIE规定必须通报的疫病,在我国属二类动物传染病,并列为检疫扑杀对象,对养牛业发展、食品安全与人类健康构成重大威胁。目前普遍采用检疫和扑杀政策控制牛结核,但各个国家执行该政策的方式差异很大。由于牛分枝杆菌存在野生动物贮主,潜伏感染普遍、无快速高通量诊断方法等原因,控制或根除牛结核病非常困难。少数发达国家成功控制或净化了牛结核,但多耗时在二十年以上,耗资巨大。新型诊断方法如IFN-γ在当代牛结核检疫中发挥日益重要的作用,野生动物与家养牛结核的免疫预防已受关注。制约我国牛结核控制和净化的原因很多,如政策法规、国家财力、技术措施和公众认知水平等,目前尚未设定全国性的牛结核控制与净化目标。  相似文献   

16.
The state of Michigan has recognized the presence of Mycobacterium bovis in its free-ranging white-tailed deer population since 1994. This endemic infection is primarily located in a 12-county area in the northeastern lower peninsula of Michigan. A statewide surveillance and eradication program of the disease has been in effect since 1994. Worldwide, Mycobacterium tuberculosis complex organisms have a known predilection toward development of antimicrobial resistance. The objective of this study was to investigate the antimicrobial susceptibility of M. bovis isolates from white-tailed deer in Michigan and detect any changes in susceptibility over time. M. bovis isolates from 2 fall hunting seasons (1999 and 2004) were used in this study. The fall season of 2004 marked the first documented case of direct transmission of M. bovis from a wild deer to a human in Michigan. Since M. bovis is a zoonotic disease, knowledge of susceptibility can expedite treatment options in humans. M. bovis isolates were obtained from 58 deer, 4 coyotes, 3 cattle, 2 raccoons, and 1 human case from the 2 years combined. Methods of susceptibility testing included 1% proportion agar plates and Bactec radiometric broth testing. M. bovis was found to be uniformly resistant to the antibiotic pyrazinamide; this resistance is common to all M. bovis isolates. No other antimicrobial resistance was found in any of the tested M. bovis isolates, which may be, in part, attributed to the lack of any significant treatment pressure in wildlife.  相似文献   

17.
Tuberculosis is present in wild animal populations in North America, Europe, Africa and New Zealand. Some wild animal populations are a source of infection for domestic livestock and humans. An understanding of the potential of each wild animal population as a reservoir of infection for domestic animals is reached by determining the nature of the disease in each wild animal species, the routes of infection for domestic species and the risk of domestic animals encountering an infectious dose. The mere presence of infection in a wild animal population does not of itself provide evidence of a significant wildlife reservoir. Although at times counterintuitive, wildlife populations with high disease prevalence may not necessarily have a role in the epidemiology of disease in domestic livestock. The key concepts used in deciding whether an infected wild animal population is involved in the epidemiology of tuberculosis in domestic livestock is illustrated by reference to six well-researched cases: the feral pig (Suis scrofa) and feral Asian water buffalo (Bubalus bubalis) in Australia, white tailed deer (Odocoileus virginianus) in Michigan, and the brushtail possum (Trichosurus vulpecula) and other species, such as the ferret (Mustela furo), in New Zealand. A detailed analysis of Mycobacterium bovis infection in the Eurasian badger (Meles meles) in Ireland and their role as a reservoir of infection for cattle is also presented.  相似文献   

18.
Bovine viral diarrhea virus (BVDV) is one of the most relevant pathogens affecting today's cattle industries. Although great strides have been made in understanding this virus in cattle, little is known about the role of wildlife in the epidemiology of BVDV. While persistently infected cattle are the most important reservoir, free-ranging ungulates may become infected with BVDV as demonstrated by serosurveys and experimental infections. Therefore, free-ranging wildlife may maintain BVDV as the result of an independent cycle and may serve as a reservoir for the virus. Systematic studies on prevalence of BVDV-specific antibodies or frequency of persistent BVDV infection in North American wildlife are sparse, and no information is available from the southeastern United States. The objective of this study was to evaluate blood and skin samples from hunter-harvested white-tailed deer (Odocoileus virginianus) for evidence of BVDV infection. Virus-neutralizing antibodies were detected in 2 of 165 serum samples. Skin biopsy immunohistochemistry (IHC) was performed on samples from 406 deer using a BVDV-specific monoclonal antibody (MAb) (15c5), and BVDV antigen was detected in one sample. A similar IHC staining pattern was obtained using a second BVDV MAb (3.12F1). Viral antigen distribution in the skin sample of this deer resembled that found in persistently infected cattle and in a previously described persistently infected white-tailed deer; thus, the deer was presumed to be persistently infected. Evidence of BVDV infection in free-ranging white-tailed deer should encourage further systematic investigation of the prevalence of BVDV in wildlife.  相似文献   

19.
Extract

Bovine tuberculosis is one of the more important animal health problems in New Zealand. In contrast to a number of other countries, the classical test and slaughter methods in New Zealand have not led to the eradication of bovine tuberculosis. The failure to eradicate bovine tuberculosis is due to the continual spread of Mycobacterium bovis from wildlife to cattle and farmed deer. Although the Australian brushtail possum Trichosurus vulpecula is the most important wildlife reservoir of infection in New Zealand, M. bovis has also been isolated from wild deer, feral pigs, feral goats, feral cats and feral cattle. In this letter we wish to report the finding of M. bovis-infected wild ferrets (Mustela putorius furo) in seven geographically distinct areas of New Zealand (Figure 1). While there are reports from overseas of M. bovis being isolated from domesticated ferrets, there are no reports of its isolation from wild ferrets or polecats (Mustela putorius)(1).  相似文献   

20.
North American wildlife is treated as a public trust resource (PTR), managed for the benefit of all people by government. Wildlife managers historically used restrictive regulations and enforced compliance to recover many species. Present-day societal needs include reducing some abundant game populations. Hunters often oppose this objective, creating tension between managing PTRs and gaining trust of hunters upon whose cooperation management depends. We assessed effects of normative and personal gains on cooperation of hunters through their purchase of antlerless deer licenses and their trust in the agency regarding bovine tuberculosis eradication from Michigan white-tailed deer. Logit modeling of hunter survey data indicated trust was influenced by procedural justice and personal gains. Only a single procedural justice variable was a statistically significant cooperation predictor. Findings suggest agencies may gain trust more readily than cooperation through procedurally just exercise of authority. Additional research is needed to identify meaningful gains associated with trust.  相似文献   

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