Latex test for rapid rotavirus diagnosis in calves

A latex agglutination test (LA) was compared with direct electron microscopy (EM) for detection of rotavirus infection in calves. A total of 375 samples from 62 calves were collected. Samples were taken when the calves were 1, 3, 5, 7, 10 and 20 days old and some scours samples were collected as well. Altogether 45/375 (12%) specimens were positive in LA and 10/375 (2.7%) were positive in EM. Samples positive in EM were also positive in LA. Out of the 62 calves studied 26/62 (42%) were positive in LA and 8/62 (13%) in EM. We found the LA very easy to perform, to be more sensitive than the EM method and probably a rather specific method for detection of rotavirus infection.     

磺胺二甲基嘧啶残留快速检测试剂条的研究

磺胺类药物残留的检测通常采用酶联免疫吸附法（ELISA）、高效液相色谱法（HPLC）及气质联用法（GC—MS）等，但这些方法有操作时间长、费用高、操作技能强等缺点，不易推广。随着人们对食品安全的日益重视和食品进出口贸易的高速增长，迫切需要一种能快速检测农、兽药残留的方法。近年来，胶体金检测技术已广泛应用于小分子物质的检测，本试验采用此技术研制了一种快速检测牛奶中磺胺二甲基嘧啶残留的胶体金试剂条，具有灵敏度高、特异性强、操作简便、成本低廉等优点，市场推广应用前景广阔。     

Evaluation of various methods for the detection of enteropathogenic Escherichia coli in diarrheic calves.

Evaluation of the Escherichia coli population in the small intestine of diarrheic calves was performed by estimating the number of colony-forming units and the observation of direct gram-stained smears of mucosal scrapings. Enterotoxigenicity of the isolates was determined by the infant mouse test and the ligated intestinal segment in calves. The influence of various broth culture media on the production of enterotoxin was also studied. Serologic characterization of the E coli isolates was performed. A total of 190 cases of diarrhea in bovine neonates was studied and it was found that enteropathogenic E coi was not responsible for more than 20% of the cases. A practical approach for the recognition of enteropathogenic E coli in a routine diagnostic laboratory is proposed.     

Sensitivity,specificity, and predictive values of reagent test strip estimations of blood urea nitrogen

Azostix-reagent-tests(R) strips (Ames, Miles, Inc., Diagnostic Division, Elkhart, IN) were used to measure blood urea nitrogen values in blood samples from 125 dogs and cats at the North Carolina State University, College of Veterinary Medicine. Results of the tests were compared with standard serum urea nitrogen results. Sensitivity, specificity, and negative predictive values were high (86.4, 90.3, and 96.5%, respectively). Positive predictive value was low, 65.5% of the dogs and cats with elevated blood urea nitrogen values were correctly classified as abnormal The test performs well when the prevalence of abnormal values is near 50%.     

Development of a monoclonal antibody-based co-agglutination test to detect enterotoxigenic Escherichia coli isolated from diarrheic neonatal calves

Escherichia coli (E. coli) strains were collected from young diarrheic calves in farms and field. Strains that expressed the K99 (F5) antigen were identified by agglutination tests using reference antibodies to K99 antigen and electron microscopy. The K99 antigen from a selected field strain (SAR-14) was heat-extracted and fractionated on a Sepharose CL-4B column. Further purification was carried out by sodium deoxycholate treatment and/or ion-exchange chromatography. Monoclonal antibodies to purified K99 antigen were produced by the hybridoma technique, and a specific clone, NEK99-5.6.12, was selected for propagation in tissue culture. The antibodies, thus obtained, were affinity-purified, characterized and coated onto Giemsa-stained Cowan-I strain of Staphylococcus aureus (S. aureus). The antibody-coated S. aureus were used in a co-agglutination test to detect K99+ E. coli isolated from feces of diarrheic calves. The specificity of the test was validated against reference monoclonal antibodies used in co-agglutination tests, as well as in ELISA. Specificity of the monoclonal antibodies was also tested against various Gram negative bacteria. The developed antibodies specifically detected purified K99 antigen in immunoblots, as well as K99+ E. coli in ELISA and co-agglutination tests. The co-agglutination test was specific and convenient for large-scale screening of K99+ E. coli isolates.     

Evaluation of four point-of-care meters for rapid determination of blood lactate concentrations in dogs

OBJECTIVE: To determine whether blood lactate values determined in dogs with 4 commercially available point-of-care meters were in agreement with values determined with a critical care laboratory blood analyzer. DESIGN: Prospective study. ANIMALS: 50 dogs evaluated for emergency treatment. PROCEDURES: Blood samples were collected at initial evaluation and processed on 4 point-of-care meters and on a critical care laboratory blood analyzer. RESULTS: All 4 point-of-care lactate meters generated measurements that were in agreement with the hospital's critical care analyzer. Values for agreement (bias) between the 4 point-of-care meters and the critical care analyzer were -0.652 (limits of agreement [LA], -1.958 to 0.654]), -0.670 (LA, -2.110 to 0.769), -0.096 (LA, -2.071 to 1.879), and -0.498 (LA, -2.616 to 1.620), respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Despite its prognostic and therapeutic relevance, blood lactate measurement in dogs has been hampered by the inability to perform the test in a timely fashion. Results of the present study indicated that several handheld point-of-care lactate meters provided results that were in agreement with a laboratory critical care blood analyzer.     

猪伪狂犬病gB抗体快速检测试纸条的研制和评价

为了建立一种猪伪狂犬病gB抗体检测试纸,为养猪业基层工作人员提供一种快速简便的狂犬病免疫抗体评价方法。胶体金标记gB蛋白作为探针,SPA和猪抗伪狂犬病病毒多抗IgG分别作为检测线和质控线,建立了猪伪狂犬病gB抗体检测试纸。猪伪狂犬病质控血清和疫苗免疫猪血清用来评价其特异性,敏感性以及与IDEXX PRV gB ELISA试剂盒的符合率试验。试验结果显示,该试纸条具有较高的特异性和敏感性,与IDEXX PRV gB ELISA试剂盒的符合率为91.04%;该免疫层析试纸条具有快速(5min)、特异、敏感等优点,不需要专门的仪器设备和专业技术人员,适合于田间推广应用。     

弓形虫抗体免疫胶体金快速检测试纸条的研制

将样品垫（加样区）、包被了弓形虫排泄分泌抗原和胶体金结合物的结合垫、包被了弓形虫排泄分泌抗原和抗弓形虫抗体的硝酸纤维素膜、吸水垫依次首尾互相衔接粘贴在白色塑料板上，组装成检测弓形虫抗体的免疫胶体金快速试纸条。然后用其进行动物弓形虫病血清抗体检测，并用弓形虫IHA诊断试剂进行对照试验。经对已知弓形虫阴、阳性血清检测，与弓形虫IHA检测结果的符合率为82．5％，金标试纸条较弓形虫IHA诊断试剂能提前2d检测到抗体。结果表明，检测弓形虫抗体免疫胶体金试剂（金标试纸条）的敏感度高于IHA。     

Evaluation of a cattle rapid test for early pregnancy diagnosis in sheep

Tropical Animal Health and Production - The early pregnancy diagnosis allows optimizing production and timely management correction, with a greater reproductive output of livestock. The Idexx Rapid...     

Determination of lactose and xylose malabsorption in preruminant diarrheic calves.

In preliminary studies feeding the poorly absorbed carbohydrate sorbitol at 2.3 g/kg body weight as an indication of maximal fermentative capacity failed to produce the expected large increase in breath hydrogen excretion but did produce a transient diarrhea in five out of six control calves. Twelve healthy control and eighteen diarrheic calves were fed lactose or D-xylose on consecutive days at 1.15 g/kg body weight and a concentration of 46 g/L. Breath and blood samples were collected at 1 h intervals from 0 to 7 h. After administration of lactose, there was a significant increase in breath hydrogen excretion in diarrheic versus control calves. The increase in plasma glucose concentrations was delayed in diarrheic calves but the area under the absorption curve was similar in control and diarrheic calves. After administration of D-xylose, breath hydrogen excretion did not increase significantly but plasma D-xylose concentrations were significantly reduced in diarrheic calves. The pathogens commonly isolated from the feces were Cryptosporidium species, rotavirus and coronavirus. The number of pathogens and the severity of the calves' acid-base deficit were not related to the severity of carbohydrate malabsorption. Decreased absorption of lactose and D-xylose may be the result of intestinal villous atrophy caused by viral or parasite infection. It was concluded that carbohydrate malabsorption rather than a specific lactose maldigestion is a significant problem in diarrheic calves. Diarrheic calves appear to digest and absorb lactose when fed in small amounts.     

Comparison of blood electrolyte and biochemical parameters between single infections of rotavirus and Cryptosporidium parvum in diarrheic Hanwoo calves

BackgroundNeonatal calf diarrhea is a major problem in the cattle industry worldwide. Rotavirus and Cryptosporidium parvum are the primary causative agents, especially during the first three weeks of the calf’s life.ObjectivesThis study investigated the differences in acid-base, electrolytes, and biochemical parameters of diarrheic calves with infection of either rotavirus or C. parvum.MethodsA total of 61 Korean native calves (≤ 20 days old) were divided into two groups based on rotavirus or C. parvum infections: rotavirus infection (n = 44) and C. parvum infection (n = 17). The calves with at a specific blood pH range (pH 6.92–7.25) were chosen for comparison. The acid-base, electrolyte, chemistry, and serum proteins were analyzed, Further, fecal examinations were performed.ResultsCompared to C. parvum-infected calves, the rotavirus-infected calves showed lower levels of total carbon dioxide, bicarbonate (HCO₃ ⁻), anion gap, total protein, and albumin/globulin ratio, and significantly lower levels of potassium, globulin, and α2-globulin (p < 0.05). The C. parvum-infected calves (r = 0.749) had stronger correlations between pH and HCO₃ ⁻ than the rotavirus-infected calves (r = 0.598). Compared to rotavirus-infected calves, strong correlations between globulin and α2-globulin, α2-globulin and haptoglobin were identified in C. parvum-infected calves.ConclusionsThis study is the first to investigate acid-base, electrolyte, and biochemical parameters in calves in response to infections of rotavirus and C. parvum. Although rotavirus and C. parvum cause malabsorptive and secretory diarrhea in similar-aged calves, blood parameters were different. This would help establish the diagnostic and treatment strategies.     

Lactobacillus GG does not affect D-lactic acidosis in diarrheic calves, in a clinical setting

D-lactate, produced by gastrointestinal fermentation, is a major contributor to metabolic acidosis in diarrheic calves. Lactobacillus rhamnosus GG survives gastrointestinal transit in the neonatal calf and does not produce D-lactate. To determine whether this probiotic reduces gastrointestinal D-lactate production or severity of diarrhea or both, 48 calves (mean, 11 days old; range, 2-30 days) admitted to the clinic for treatment of diarrhea were randomly allocated to 2 groups. The experimental group was given Lactobacillus rhamnosus GG (1 x 10(11) cfu/d) PO, dissolved in milk or oral electrolyte solution, in addition to clinic treatment protocols; the other group served as a control. Serum and fecal samples were obtained at admission and at 24 and 48 hours after initial administration of Lactobacillus rhamnosus GG. All samples were analyzed for D- and L-lactate by using high-pressure liquid chromatography. Feces were also analyzed for pathogens, Lactobacillus rhamnosus GG recovery, and dry matter. D-lactic acidemia (>3 mmol/L) was present in 37/48 calves at admission. Lactobacillus rhamnosus GG was recovered in the feces of 13 experimental calves and 0 control calves 24 hours after administration. No difference in serum or fecal D- or L-lactate between the groups was detected at any time point. After therapy, D-lactic acidosis was absent at 48 hours in all but 1 calf. No relation between fecal pathogen (viral, bacterial, or protozoal) and degree of D-lactic acidosis was observed. The reduction in mortality and greater fecal dry matter in Lactobacillus rhamnosus GG-treated calves was not statistically significant.     

Performance of the Ascensia ENTRUST glucose meter for determination of blood glucose concentration in rats

Background: The Ascensia ENTRUST blood glucose meter is intended for self‐monitoring of blood glucose by diabetic patients. Use of such a glucometer would minimize blood volume requirements for the measurement of glucose in small laboratory animals. Objective: The purpose of this study was to assess the performance of the Ascensia ENTRUST for measuring glucose in whole blood from Wistar rats by evaluating the effect of anticoagulant and sample processing delay and comparing normalized results with plasma glucose concentration. Methods: Blood samples were collected from the retroorbital sinus of 30 male Wistar rats with a wide range of blood glucose concentrations. Glucose concentration was measured with the Ascensia ENTRUST in nonheparinized (NH) and heparinized samples immediately after collection (Hep‐0) and in heparinized samples after a 15 min delay at 23–28°C (Hep‐15). Heparinized samples were centrifuged and glucose concentration was determined in plasma using an automated chemistry analyzer. Results were compared to assess the effect of anticoagulant (NH vs Hep‐0) and time (Hep 0 vs Hep 15), and to compare normalized Hep‐15 results with plasma glucose concentration. Results: Glucose concentration was not significantly different between NH and Hep‐0 samples. Glucose concentration was lower in Hep‐15 (77±36.9 mg/dL) than Hep‐0 (88±39.7 mg/dL) samples, but the difference was not significant. With normalization, Hep‐15 glucose concentration correlated well (r≥.98) with plasma glucose concentration but was lower by 6.0±16.7 mg/dL, with a positive bias at low glucose concentrations and a negative bias at high concentrations. Conclusion: The Ascensia ENTRUST may be adequate for repeated blood glucose measurements in rats, but its results do not accurately predict plasma glucose concentrations measured by an automated clinical chemistry analyzer.