Multilocus sequence typing as a tool for studying the molecular epidemiology and population structure of Brachyspira hyodysenteriae     

Tom La  Nyree D. Phillips  Belinda L. Harland  Phatthanaphong Wanchanthuek  Matthew I. Bellgard  David J. Hampson   《Veterinary microbiology》2009,138(3-4):330-338

The purpose of this study was to develop and apply a multilocus sequence typing (MLST) scheme to study the molecular epidemiology of Brachyspira hyodysenteriae, the aetiological agent of swine dysentery. Sequences of seven conserved genomic loci were examined in 111 B. hyodysenteriae strains. Fifty-eight of these previously had been analysed by multilocus enzyme electrophoresis (MLEE), and for some the results of pulsed field gel electrophoresis (PFGE), restriction endonuclease analysis (REA) and/or serotyping also were available. The discriminatory power of these methods was compared. The strains were divided into 67 sequence types (STs) and 46 amino acid types (AATs) by MLST. The Index of Association value was significantly different from zero, indication that the population was clonal. Eleven clonal complexes (Cc) comprising between 2 and 10 STs were recognised. A population snapshot based on AATs placed 77.5% of the isolates from 30 of the AATs into one major cluster. The founder type AAT9 included 13 strains from nine STs that were isolated in Australia, Sweden, Germany and Belgium, including one from a mallard. The MLST results were generally comparable to those produced by MLEE. The MLST system had a similar discriminatory power to PFGE, but was more discriminatory than REA, MLEE or serotyping. MLST data provided evidence for likely transmission of strains between farms, but also for the occurrence of temporal “micro-evolution” of strains on individual farms. Overall, the MLST system proved to be a useful new tool for investigating the molecular epidemiology and diversity of B. hyodysenteriae.  相似文献   

Characterisation of Escherichia fergusonii isolates from farm animals using an Escherichia coli virulence gene array and tissue culture adherence assays     

Wragg P  La Ragione RM  Best A  Reichel R  Anjum MF  Mafura M  Woodward MJ 《Research in veterinary science》2009,86(1):27-35

Escherichia fergusonii has been associated with a wide variety of intestinal and extra-intestinal infections in both humans and animals but, despite strong circumstantial evidence, the degree to which the organism is responsible for the pathologies identified remains uncertain. Thirty isolates of E. fergusonii collected between 2003 and 2004 were screened using an Escherichia coli virulence gene array to test for the presence of homologous virulence genes in E. fergusonii. The iss (increased serum survival) gene was present in 13/30 (43%) of the test strains and the prfB (P-related fimbriae regulatory) and ireA (siderophore receptor IreA) genes were also detected jointly in 3/30 (10%) strains. No known virulence genes were detected in 14/30 (47%) of strains. Following confirmatory PCR and sequence analysis, the E. fergusoniiprfB, iss and ireA genes shared a high degree of sequence similarity to their counterparts in E. coli, and a particular resemblance was noted with the E. coli strain APEC O1 pathogenicity island. In tissue culture adherence assays, nine E. fergusonii isolates associated with HEp-2 cells with a ‘localised adherence’ or ‘diffuse adherence’ phenotype, and they proved to be moderately invasive. The E. fergusonii isolates in this study possess both some phenotypic and genotypic features linked to known pathotypes of E. coli, and support existing evidence that strains of E. fergusonii may act as an opportunistic pathogens, although their specific virulence factors may need to be explored.  相似文献   

Defining output-based standards to achieve and maintain tuberculosis freedom in farmed deer, with reference to member states of the European Union     

Simon J. More  Angus R. Cameron  Matthias Greiner  Richard S. Clifton-Hadley  Sandra Correia Rodeia  Douwe Bakker  Mo D. Salman  J. Michael Sharp  Fabrizio De Massis  Alicia Aranaz  M. Beatrice Boniotti  Alessandra Gaffuri  Per Have  Didier Verloo  Michael Woodford  Martin Wierup 《Preventive veterinary medicine》2009,90(3-4):254-267

Within the European Union (EU), detailed legislation has been developed for cattle, but not deer, to minimise disease risks associated with trade in animals and animal products. This legislation is expressed as input-based standards, providing a detailed outline of the activity required (for example, testing of animals and application of defined control measures), on the expectation that an adequate output (for example, confidence in freedom) will be achieved. Input-based standards are at odds with the increasing shift towards output-based standards, particularly in OIE rules governing international trade. In this paper, we define output-based standards to achieve and maintain freedom from tuberculosis (TB) in farmed deer, with reference to EU member states. After considering the probability of freedom achieved for cattle under existing EU legislation, we defined a ‘free farmed deer holding’ as one with a probability of freedom from infection of at least 99%. We then developed an epidemiological model of TB surveillance systems for deer holdings, incorporating different surveillance strategies, including combinations of diagnostic tests, and a variety of different scenarios relating to the potential for introduction of infection. A range of surveillance strategies were identified to achieve and maintain a free farmed deer holding, and worked examples are presented. The surveillance system sensitivity for varying combinations of screening and confirmatory tests in live animals, animals at slaughter and on-farm deaths is also presented. Using a single test at a single point in time, none of the TB tests routinely used in farmed deer is able to achieve an acceptable probability of TB freedom. If repeat testing were undertaken, an acceptable probability of TB freedom could be achieved, with differing combinations of the surveillance system sensitivity, frequency of testing and risk of introduction. The probability of introduction of infection through the importation of infected deer was influenced by the use of a pre-movement test (assumed 90% test sensitivity and negative test results), the TB prevalence in the source herd and the number of animals imported. A surveillance system sensitivity of at least 81% was achieved with different combinations of annual live animal surveillance and surveillance of animals at slaughter or on-farm deaths. This methodology has broad applicability and could also be extended to other diseases in both deer and other species with relevance to trade in animals and animal products.  相似文献   

Effect of mitratapide on body composition, body measurements and glucose tolerance in obese Beagles     

Britta Dobenecker  Manuelle De Bock  Marc Engelen  Lieve Goossens  Armin Scholz  Ellen Kienzle 《Veterinary research communications》2009,33(8):839-847

The objective of this study was to confirm that weight loss after treatment with mitratapide (Yarvitan®) is loss of adipose tissue. Obese dogs were treated with the recommended treatment schedule of mitratapide. Dual-energy X-ray absorptiometry (DEXA) was done before and after the treatment schedule. Body weight, feed consumption and pelvic circumference were recorded and a glucose tolerance test was performed. Dual-energy X-ray absorptiometry measurements showed an impressive loss of fat tissue, corresponding to a mean loss of approximately 41.6% of the body fat mass recorded before treatment. After treatment with mitratapide, the mean body fat percentage had returned within the normal range. At the end of the study, the dogs had lost on average 14.2% of their body weight and 15.2% of their pelvic circumference compared to baseline. The results also suggest that losing weight with mitratapide might help to reverse insulin resistance.  相似文献   

4种教槽料对乳猪生长性能、腹泻和皮毛的影响     

詹黎明  吴德  李勇 《饲料广角》2009,(9):43-46

试验选取胎次相近（2～3胎）和分娩日龄相差7d左右的长×大二元母猪24头．随机分为4个处理组．各处理组哺乳仔猪从5日龄开始补料,分别饲喂A、B、C和D4种教槽料。结果表明：母猪从分娩到断奶期间总采食量个体间没有显著差异（P〉0．05）。1～4d和4～21d．仔猪日增重和采食量无显著差异（P〉0．05）;4～28d和全程（1＋28d）仔猪日增重差异不显著（P〉0．05）。21～28d生长阶段,B组仔猪采食量和日增重均显著高于A、C和D组（P〈0．05）：B组公猪日增重显著高于A组（P〈0．05）;B组母猪日增重显著高于A、C和D组（P〈0．05）;负增重比例,B组较其他3组最低。仔猪在各阶段腹泻率差异均不显著（P〉0．05）：断奶后7d．B和C组腹泻仔猪与D和A组差异显著（P〈0．05）。B和C组的仔猪皮毛光滑程度高于A和D组。以上结果表明B组教槽料对仔猪生产性能和减少腹泻情况的效果最好．  相似文献   

4种教槽料对断奶仔猪生长性能、腹泻和皮毛的影响   总被引：1，自引：0，他引：1  

詹黎明  吴德  李勇 《饲料与畜牧》2009,(5):33-35

试验选取160头体重7．02．4±0．505kg的健康断奶仔猪,随机分4个处理,每个处理4个重复,每个重复10头猪。分别饲喂粉料^组、扮料B组、颗粒料C组和粉料D组。结果表明：断奶后10d试验期内,扮料A组仔猪采食量和日增重均显著高于粉料B组和颗柱料C组（P〈0．05）,与粉料D组差异不显著（P〉0．05）;粉料B组和颗粒料C组采食量．日增重均差异显著（P〈0．05）。粉料A组仔猪料肉比与扮料B组和颗粒料C组差异均显著（P〈0．0,5）,与粉料D组相比,粉料A组料肉比降低4．76％。腹泻率和腹泻指数粉料A组和粉料D组间差异不显著（P〉0．05）,但与粉料B组和颗拉料C组间差异显著（P〈0．05）。除颗粒料C组皮毛指数与各组存在显著差异外（P〈0．05）,各组间均差异不显著（P〉0．05）。以上结果表明,粉料A和粉料D提高断奶仔猪生产性能、降低仔猪腹泻率、生产效果最佳。  相似文献   

Second order Horner's syndrome in a cat     

Luisa De Risio  James Fraser McConnell 《Journal of Feline Medicine and Surgery》2009,11(8):714-716

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Two cases of feline ectromelia: autopodium ectromelia associated with humero-ulnar synostosis and zeugopodium ectromelia     

Francesco Macrì  Massimo De Majo  Giuseppe Rapisarda  Giuseppe Mazzullo 《Journal of Feline Medicine and Surgery》2009,11(8):731-734

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Estimating the Risk of a Crop Epidemic From Coincident Spatio-temporal Processes     

Murali Haran  K. Sham Bhat  Julio Molineros  Erick De Wolf 《Journal of Agricultural, Biological & Environmental Statistics》2010,15(2):158-175

Fusarium Head Blight (FHB), or “scab,” is a very destructive disease that affects wheat crops. Recent research has resulted in accurate weather-driven models that estimate the probability of an FHB epidemic based on experiments. However, these predictions ignore two crucial aspects of FHB epidemics: (1) An epidemic is very unlikely to occur unless the plants are flowering, and (2) FHB spreads by its spores, resulting in spatial and temporal dependence in risk. We develop a new approach that combines existing weather-based probabilities with information on flowering dates from survey data, while simultaneously accounting for spatial and temporal dependence. Our model combines two space-time processes, one associated with pure weather-based FHB risks and the other associated with flowering date probabilities. To allow for scalability, we model spatiotemporal dependence via a process convolutions approach. Our sample-based approach produces a realistic assessment of areas that are persistently at high risk (where the probability of an epidemic is elevated for extended time periods), along with associated estimates of uncertainty. We conclude with the application of our approach to a case study from North Dakota.  相似文献   

An empirical equation to calculate soil solution electrical conductivity at 25°C from major ion concentrations     

F. Visconti  J. M. De Paz  J. L. Rubio 《European Journal of Soil Science》2010,61(6):980-993

The electrical conductivity at 25°C (EC₂₅) of soil solutions or irrigation waters is the standard property for assessing salinity. Many models for soil salinity prediction calculate the major ion composition of the soil solution. The electrical conductivity of a solution can be determined from its composition through several different empirical equations. An assessment of these equations is necessary to incorporate the most accurate and precise equations in such models. Twelve different equations for the EC₂₅ calculation were calibrated by means of regression analyses with data from 133 saturation extracts and another 135 1:5 soil‐to‐water extracts from a salt‐affected agricultural irrigated area. The equations with better calibration parameters were tested with another data set of 153 soil solutions covering a wide range of salt concentrations and compositions. The testing was conducted using the standardized difference t‐test, which is a rigorous validation test used in this study for the first time. The equations based on the ionic conductivity decrement given by Kohlrausch's law presented the poorest calibration parameters. The equations founded on the hypothesis that EC₂₅ is proportional to analytical concentrations had worse calibration and validation parameters than their counterparts based on free‐ion concentrations and ionic activities. The equations founded on simpler mathematical relationships generally gave improved validation parameters. The three equations based on the specific electrical conductivity definition presented a mean standardized difference between observations and predictions indistinguishable from zero at the 95% confidence level. The inclusion of the charged ion‐pair concentrations in the equation based on free‐ion concentrations improved its predictions, particularly at large electrical conductivities. This equation can be reliably used in conjunction with chemical speciation software to assess EC₂₅ from the ion composition of soil solutions.  相似文献