动物疫病监测样品采集的注意问题

实验室检测是目前动物疾病诊断的重要内容,特别是传染性疫病更离不开实验室检测,实验结果的准确性、有效性除实验方法、检测试剂、实验操作等因素影响外,从一开始就受到样品的采集、保存、运输等因素的影响。特别是在开展动物疫病的监测工作,监测结果是否具有代表性,是否能够真实反映出疫病的真实情况都与监测样品的采集有重要关系。     

动物疫病监测样品采集应注意的事项

实验室检测是目前动物疾病诊断的重要内容,特别是传染性疫病更离不开实验室检测.实验结果的准确性、有效性除受实验方法、检测试剂、实验操作等因素影响外,从一开始就受到样品的采集、保存、运输等因素的影响.特别是在开展动物疫病的监测工作,监测结果是否具有代表性,是否能够真实反映出疫病的真实情况,都与监测样品的采集有重要关系.     

动物样品采样方法及采样中常见的问题

<正>近年来,实验室监测在重大动物疫病的诊断及防控中发挥了不可取代的重要作用。而实验室监测结果的准确性、有效性除受实验方法、实验设备、监测试剂、实验操作等因素影响外,还要受到样品的采集、运输、保存等因素的影响。动物病料样品的采集是动物疫病实验室检验工作中的重要内容。怎样采集动物病料、采集时机、样品的处理和保存、运送是否合适等,都直接关系到检验结果的准确性及可靠性,对动物疫病的诊断、流     

几种畜禽病料采集技术

采集检测样品是诊断检测工作的重要内容。采样的时机是否适宜,样品是否具有代表性,样品处理、保存、运送是否合适及时,与检验结果的准确性、可靠性关系极大。一、畜禽病料采集技术1.样品采集的原则(1)适时采样。根据检测要求及检测对象和检验项目的不同,选择适当的采样时机十分重要。应严格按规定时间采样,有临床症状需要作病原分离的,样品必须在病初的发热期或症状典型时采样,病死的动物应立即采样。     

样品采集的注意事项

样品的采集、保存、运输和处理决定着检测工作的成败,是实验室操作质控体系的一个重要环节.本文综述了样品的采集、记录、保存和运输以及样品处理的注意事项,为给实验室检测工作提供合格的检测样品提供参考.     

动物疫病监测样品采集运送保存应注意的问题

在动物疫病的防控中,实验室监测有着不可取代的重要作用。实验室监测结果的准确性、有效性,是否能够反映出疫病的真实情况,都与监测样品的采集、运输、保存等有重要关系。规范化的样品采集、运输、保存是质量控制动物疫病诊断和监测工作至关重要的一环。     

浅谈动物检测样品的采集、保存、运输

<正>动物病料样品的采集是动物疾病诊断、流行病学调查或免疫监测所不可缺少的重要步骤,而实验室检测结果的准确性、有效性除受实验方法、检测试剂、实验操作等因素的影响外,还要受到样品的采集,运输、保存等因素的影响。本文通过检测样品在采集、保存和运输过程中必须注意的几个主要环节,说明样品是监测工作顺利开展的基础,也决定了实验结果的可靠性。1样品采集原则1.1剖检基本条件凡发现患畜急性死亡怀疑是炭疽,则不可随意解剖,应采取     

家禽血液样品的采集技术及应用

血液样品采集技术直接影响血样的质量,进而影响到免疫效果和疫情监测结果的准确性。综合业内常用的各种作法,结合实践体会,对翅内侧翼下静脉采血、跖骨内侧静脉采血、右侧颈静脉采血、心脏采血等采血方法及血清的制备方法,就操作要领、方法应用与选择(家禽种类及日龄、需要血量多少)、方法评价等进行了较为详细的描述和总结,对血液样品采集过程中各关键操作环节提出了注意事项。     

基层监测采样问题的解决措施

采样监测是兽医实验室检测工作的基础,样品质量是否符合要求直接关系到检测结果的准确度,基层采样过程中存在着血清溶血、样品受污染、样品采集保存不规范等问题进行分析,建议使用负压采血管、严格采样规程等措施加以改进。     

样品采集的生物安全与防范措施

在兽医科研和日常诊断检测工作中,样品采集是必不可少的工作。在进行样品采集时,在保证样品质量的同时,必须注意采样人员的生物安全防护工作,保证采样人员的身体健康[1-2]。1采样生物安全1.1活体采样时动物自身的活动有可能产生新的危害,如抓、咬伤工作人员等。1.2危害的情况也可能是由于工作人员操作不小心或正在使用的器材设备等引起的,如刀片割破、针头     

The adequacy of sample type/weight and incubation period on detection of Salmonella spp. in slaughter cattle.

The purpose of this study was to examine the adequacy of different sample types (fecal and rumen content), rumen-content sample weight (1, 10, and 25 g), and incubation period on the detection of Salmonella spp. in grass-fed beef cattle at slaughter. The culture technique was the same for all samples and followed the Australian Standard (AS 1766.2.5-1991). Sample adequacy was defined as the ratio between the overall prevalence, as obtained from samples identified as positive by any sample type/weight, and the estimated prevalence, as obtained from samples identified as positive by a particular sample type/weight. Sample adequacy reflects the likelihood of a sample of a particular type and weight to contain the organism of interest and hence is related to the sensitivity of the diagnostic test. It was found that sample adequacy differed between sample types and weights: 37.5% for both a 10-g fecal sample and a 1-g rumen sample, 77.1% for a 10-g rumen sample, and 79.2% for a 25-g rumen sample. On this basis, it is strongly recommended that sample type and weight be considered in the design of studies that aim to quantify Salmonella contamination in cattle.     

玉米干酒糟及其可溶物有效能值估测模型中定标样品选择方法的研究

本试验旨在探讨玉米干酒糟及其可溶物(DDGS)有效能值估测模型中定标样品的选择原则。从23个玉米DDGS样品(定义为全样品库)中按酶水解物能值(EHGE)相差0.21 MJ/kg左右的梯度选择9个定标玉米DDGS样品,定义为选择性样品库;将剩余的14个玉米DDGS样品定义为非选择性样品库。然后,比较选择性样品库与非选择性样品库化学成分含量及变异的差异,以及通过全样品库和选择性样品库分别建立其化学成分对EHGE之间的回归模型,比较根据回归模型计算得到的非选择性样品库EHGE的差异。结果表明,选择性样品库和非选择性样品库的玉米DDGS在粗蛋白质(CP)、粗灰分(Ash)、粗脂肪(EE)、粗纤维(CF)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)含量及EHGE平均值上均无显著性差异(P0.05),CP、Ash、EE、CF、ADF、NDF含量及EHGE变异的方差上均无显著性差异(P0.05)。选择性样品库和非选择性样品库化学成分含量在第一、二主成分得分载荷分布上,选择性样品库中仅1个玉米DDGS样品未与非选择性样品库的分布范围重叠。以选择性样品库样品建立的EHGE预测模型为EHGE=(3 566+53.94×EE-32.68×NDF)×4.184/1 000(R2=0.798 1,RSD=0.43 MJ/kg);以全样品库样品建立的预测模型为EHGE=(3 742+29.67×EE-29.71×NDF)×4.184/1 000(R2=0.535 0,RSD=0.44 MJ/kg)。由2个模型获得的非选择性样品库(n=14)玉米DDGS的EHGE计算值与其实测值的绝对残差平均值分别为0.47和0.33 MJ/kg,差异不显著(P0.05)。综上所述,在玉米DDGS有效能值的估测建模中,以EHGE作为定标样品的选择依据是可行的。     

Estimation of Salmonella prevalence on individual-level based upon pooled swab samples from swine carcasses

Pooling of samples might be an effective means to increase cost-effectiveness in routine surveillance. The present study assessed the effect on the sensitivity of detection of Salmonella when pooling swab samples from swine carcasses compared to individual analyses. A total of 18,984 samples from nine Danish swine abattoirs were collected during 1 year, covering 2017 slaughter days. At each abattoir, swab samples were taken on a daily basis from 10 carcasses randomly selected. From each carcass, an area of 3 cm x 100 cm was swabbed. Five of these samples were analysed individually and the other five were analysed as one pooled sample. Standard culture methods were used. A logistic regression model was built, where the response was whether a sample was Salmonella positive or not. The explanatory factors were abattoir, type of sampling (individual or pooled sample), and season of year 2000 (four quarters). The odds ratio (OR) of the effect of type of sampling in the logistic model accounting for abattoir and season was interpreted as the conversion factor between pooled and individual sample prevalence. The results of the individually analysed samples showed a low prevalence of Salmonella (1.4%). When Salmonella was isolated, mostly only one positive sample was found among the five individually analysed samples per slaughter day. On a few days >1 positive samples' were found (9 out of 2017 days approximately 0.4%). The pooled sample prevalence was 4.1%. Because the individual prevalence was low, the pooled sample prevalence would have been around five times higher than the individual-level prevalence-if there had been no loss of sensitivity. However, we found that due to loss of sensitivity the pooled prevalence was only three times higher (OR = 2.7; CI 2.0-3.7). Therefore, a conversion factor of 3 instead of 5 should be applied to calculate the individual prevalence from a pooled prevalence. This approach has been used in the national surveillance of Danish pork since 2001. The estimated conversion factor and accept of pooling samples do not necessarily apply to a population with a higher prevalence or to other types of samples (e.g. faeces or lymph nodes) or diagnostic procedures.     

Differences in total protein concentration, nucleated cell count, and red blood cell count among sequential samples of cerebrospinal fluid from horses

OBJECTIVE: To examine total protein concentration and cell counts of sequentially collected samples of CSF to determine whether blood contamination decreases in subsequent samples and whether formulas used to correct nucleated cell count and total protein concentration are accurate. DESIGN: Case series. ANIMALS: 22 horses. PROCEDURE: For each horse, 3 or 4 sequential 2-ml samples of CSF were collected from the subarachnoid space in the lumbosacral region into separate syringes, and blood was obtained from the jugular vein. Total protein concentration, nucleated cell count, and RBC counts were determined in all samples. RESULTS: Among 3 sequential samples, total protein concentration and RBC count were significantly lower in samples 2 and 3, compared with sample 1. Nucleated cell count was significantly lower in sample 3, compared with sample 1. Among 4 sequential samples, total protein concentration and RBC count were significantly lower in samples 2, 3, and 4, compared with sample 1. Nucleated cell count was significantly lower in samples 3 and 4, compared with sample 1. For 3 correction formulas, significant differences in corrected values for nucleated cell count and total protein concentration were detected between sample 1 and sample 3 or 4. CONCLUSIONS AND CLINICAL RELEVANCE: Because iatrogenic blood contamination decreases in sequential CSF samples, a minimum of 3 samples should be collected before submitting the final sample for analysis. Formulas to correct nucleated cell count and total protein concentration are inaccurate and should not be used to correct for blood contamination in CSF samples.     

Comparison of sampling techniques for measuring the antimicrobial susceptibility of enteric Escherichia coli recovered from feedlot cattle

OBJECTIVE: To evaluate the effectiveness of various sampling techniques for determining antimicrobial resistance patterns in Escherichia coli isolated from feces of feedlot cattle. SAMPLE POPULATION: Fecal samples obtained from 328 beef steers and 6 feedlot pens in which the cattle resided. PROCEDURE: Single fecal samples were collected from the rectum of each steer and from floors of pens in which the cattle resided. Fecal material from each single sample was combined into pools containing 5 and 10 samples. Five isolates of Escherichia coli from each single sample and each pooled sample were tested for susceptibility to 17 antimicrobials. RESULTS: Patterns of antimicrobial resistance for fecal samples obtained from the rectum of cattle did not differ from fecal samples obtained from pen floors. Resistance patterns from pooled samples differed from patterns observed for single fecal samples. Little pen-to-pen variation in resistance prevalence was observed. Clustering of resistance phenotypes within samples was detected. CONCLUSIONS AND CLINICAL RELEVANCE: Studies of antimicrobial resistance in feedlot cattle can rely on fecal samples obtained from pen floors, thus avoiding the cost and effort of obtaining fecal samples from the rectum of cattle. Pooled fecal samples yielded resistance patterns that were consistent with those of single fecal samples when the prevalence of resistance to an antimicrobial was > 2%. Pooling may be a practical altemative when investigating patterns of resistance that are not rare. Apparent clustering of resistance phenotypes within samples argues for examining fewer isolates per fecal sample and more fecal samples per pen.     

醉马草化学成分预试及毒性部位筛选

以春秋两季醉马草样品作为试验材料,粉剂样品分别做系统预试验比较所含主要成分种类和数量上的差异,并通过分光光度法测定了2种材料的生物碱和黄酮含量;分别用不同极性溶剂制作的悬浮液,做毒性筛选试验。结果表明,春季材料含的生物碱类成分远远超过秋季材料,而秋季材料所含的黄酮类成分远远超过春季材料;毒理试验表明,毒性成分主要集中在春季材料的950 mL/L乙醇提取部分。     

Evaluation of EDTA hematology tubes for collection of blood samples for tests of secondary hemostasis in dogs

OBJECTIVE: To evaluate the use of EDTA tubes for collection of blood samples for assays of secondary hemostasis in dogs. ANIMALS: 108 dogs of various ages, breeds, and sexes (19 healthy and 89 with abnormalities of secondary hemostasis). PROCEDURES: Blood samples were collected via cephalic venipuncture and transferred to sodium citrate tubes and EDTA tubes. Plasma was harvested from each type of tube for assays of concentrations of fibrinogen and D-dimer as well as prothrombin time, activated partial thromboplastin time, and antithrombin activity. Intra-assay and interassay precision and correlation coefficients for all hemostatic tests were calculated for each type of plasma sample. The effect of storage conditions on assay results for the 2 types of plasma samples was also evaluated. RESULTS: Results of hemostatic tests were highly correlated between citrated and EDTA-treated plasma samples. Intra-assay imprecision for all hemostatic tests with the exception of D-dimer concentration was < 10% for both citrated and EDTA-treated plasma samples; interassay imprecision was higher for EDTA-treated versus citrated plasma samples. Storage of plasma samples for 1 hour did not result in significantly different assay results for either type of plasma sample, but storage for 2 hours significantly affected values for EDTA-treated plasma samples. CONCLUSIONS AND CLINICAL RELEVANCE: Although evaluation of the sensitivity and specificity of hemostatic tests that use EDTA-treated plasma samples is required, EDTA may be a suitable alternative to sodium citrate as an anticoagulant for use in hemostatic testing in conditions in which tests could be performed within 1 hour after sample collection.     

The effect of sampling time and sample handling on the detection of Staphylococcus aureus in milk from quarters with subclinical mastitis

Staphylococcus aureus mastitis is an important cause of economic loss for the dairy industry. Control programs rely on the timely and accurate identification of positive quarters. The effects of sampling time and sample handling were examined in an attempt to improve the accuracy of detection of S. aureus. Premilking and postmilking milk samples were collected from 55 lactating quarters with subclinical S. aureus infection. Each sample was divided into 2 aliquots; one of which was cultured fresh, the other was frozen at -20 degrees C for 14 days before being cultured. Analysis of variance was used to determine the effect of sampling time (premilking vs postmilking) and sample handling (fresh vs frozen) on the detection of S. aureus, as measured by the mean category for colony-forming units per millilitre (cfu/mL). A stratified analysis was required, due to interaction between sampling time and sample handling. Only a fresh postmilking sample was inferior, yielding a lower mean category for cfu/mL (P < 0.05). The ability to detect S. aureus in quarters with subclinical intramammary infection, as measured by the mean category of cfu/mL, was maximized in fresh or frozen premilking samples and in frozen postmilking samples.     

Pedigree analysis of four decades of Quarter Horse breeding

Pedigrees of randomly selected Quarter Horses born in each of the years 1946, 1956, 1966 and 1976 and of winning halter, cutting and race horses born in the same years were evaluated and compared. Average inbreeding and inter se relationship levels and relationships of influential ancestors to the sample were calculated for each sample. The amount of Thoroughbred influence and the average generation interval were also determined for each random sample. The levels of inbreeding found in the random samples were low, ranging from 1.3% in 1956 to 2.6% in 1966; however, these levels were higher than would be expected if mating were random. Show and race winners born in 1976 appeared to be less inbred than random horses of the breed. The estimated average inter se relationship within the random samples increased from 0% in 1946 to 3% in 1966, decreasing again to 0% in 1976. Horses in the elite samples appeared to be more closely related to each other than those in the random samples. Fifteen ancestors of horses in the random samples were identified as influential to the Quarter Horse breed. Many of these same ancestors were influential in the halter and cutting samples, but only one was influential in the race samples. The percentage of pedigree lines in the random samples that contained a Thoroughbred ancestor were as follows; 1946, 27.5%; 1956, 19.2%; 1966, 23.2% and 1976, 31.4%. The average generation interval fluctuated from approximately 8 yr to approximately 10 yr for the random samples.