A comparison of standard serological tests for the diagnosis of bovine brucellosis in Canada.

Six agglutination and two complement fixation tests were compared with respect to specificity, sensitivity and relative sensitivity for the serodiagnosis of bovine brucellosis. Based on 1051 sera from brucellosis free herds, the specificity of the tests was 98.9% for the buffered plate antigen test (BPAT), 99.2% and 99.3% for the standard tube and plate agglutination tests (STAT and SPAT), respectively, and 99.8% for the 2-mercaptoethanol test (2MET). On this small sample, the rose bengal plate test (RBPT), card test (CARD) and the complement fixation test (CFT) correctly classed all sera as negative. On a sample of 167 culture positive cattle, the sensitivities of the tests were CFT: 79.0%, BPAT: 75.4, RBPT: 74.9%, CARD: 74.3%, SPAT: 73.1%, STAT: 68.9%, and 2MET: 59.9%. All tests combined detected only 82% of these infected cattle. Analysis of the relative sensitivity of the six agglutination tests gave the following ranking: BPAT greater than RBPT greater than CARD greater than SPAT greater than STAT. The 2MET ranked between the BPAT and RBPT or between the RBPT and CARD depending on the analysis used. The use of the BPAT as a screening test is recommended provided that a test of high specificity and sensitivity such as the CFT is used to confirm screening test reactions.     

Potential use of lymphocyte blastogenic responses in diagnosis of bovine tuberculosis

A comparison of in vitro lymphocyte responses and delayed type tuberculin skin test responses was made in an animal experimentally exposed to a Mycobacterium bovis-infected animal and in cattle naturally infected with M. bovis. Tuberculin skin tests did not suppress in vitro lymphocyte responses to M. bovis PPD and to M. avium PPD tuberculin. The whole blood test used in these studies provided for considerable savings in time as compared to use of purified lymphocytes for evaluating in vitro cellular responses. Variations in the responsiveness of lymphocytes to specific mycobacterial antigens was observed, therefore, it is recommended that profiles be established using three or more tests conducted at 14-day intervals.     

Field trial of six serological tests for bovine brucellosis

Serum agglutination (SAT), complement fixation (CFT), indirect ELISA (iELISA), competitive ELISA (cELISA), Rose Bengal (RBT) and EDTA-modified agglutination (EDTA) tests were used in parallel on serological samples from 19,935 cattle in 301 herds. The study herds were selected according to putative exposure to Brucellaabortus with cases defined by bacteriological culture or test agreement. No single test identified all infected cattle and, at diagnostic thresholds, relative sensitivity was highest in the iELISA (67.9%) or RBT (78.1%), using bacteriological culture or test agreement, respectively, to define cases. As screening tests, the relative sensitivity of the SAT was highest (75.9% by culture or 84.9% by test agreement), with an optimal threshold of 31 IU. The relative specificity of the diagnostic tests ranged from 99.6% (SAT 31IU) to 100% (iELISA, RBT and CFT). The trial confirmed the value of the SAT as a screening test and the value of parallel testing.     

Comparison of four serological tests in the diagnosis of caprine brucellosis

Results from four serological tests for diagnosing brucellosis--serum tube agglutination (SAT), agar gel immunodiffusion (AGIT), Rose Bengal plate (RBPT) and complement fixation (CFT)--were compared using sera from goats from farms infected with Brucella melitensis. Ninety-two goats were negative and 29 positive to all four tests. The remaining 85 reacted to one or more tests. The RBPT was the most sensitive test and the AGIT the most specific, when compared with the CFT. The results suggest that the SAT adds little information when used with other tests but that RBPT and AGIT are useful for testing caprine brucellosis where facilities for the CFT are not available.     

布鲁氏菌弱毒疫苗粘膜免疫及检测方法的研究

为研究布鲁氏菌弱毒疫苗粘膜免疫及其检测方法,本实验采用粘膜点眼途径对健康母羊接种布鲁氏杆菌猪2号疫苗(S2)、牛19号疫苗(A19)和羊强毒株(M16),筛选布鲁氏杆菌病鉴别检测方法。将12月龄～14月龄母羊60只随机分为3组,以常规疫苗推荐剂量进行半量粘膜点眼接种。采集血液、淋巴、脏器进行布鲁氏菌病血清学检测和细菌学分离以及PCR检测。结果表明:布鲁氏菌弱毒疫苗抗体水平持续6个月,其中血清学的试管凝集试验、半胱氨酸凝集试验与补体结合试验的阳性符合率达到100%。细菌分离期为6个月,乳腺、乳腺淋巴、髂淋巴分离率较高;而强毒株M16的抗体水平和细菌分离持续12个月以上。结果显示以常规血清学和细菌学检测方法在点眼免疫布鲁氏菌S2、A19苗6个月后可以进行野毒感染和疫苗免疫畜的鉴别诊断。     

The vaginal mucus agglutination test in the diagnosis of bovine brucellosis

Of 1140 vaginal mucus agglutination tests (VMAT) on specimens obtained in 1971-72 from 663 dairy cows in seven herds infected with brucellosis, 97 were positive. When the VMAT was positive one or more serological tests were also positive. Of the 97 corresponding serum agglutination tests 80 sera had titres of more than 533 international units. Only 69.8 per cent of VMAT from serologically positive cows were positive. No evidence was found of non-specific agglutinins in vaginal mucus and positive VMAT reactions appeared to be specific for field infection. Three cows showed evidence of local agglutinins in the vagina. Hence herd testing by VMAT has no advantage over tests of blood serum but the test could be an aid in establishing whether individual cattle are infected.     

北方三省区梅花鹿间布鲁氏菌病的流行病学调查

为了摸清布鲁氏菌病在我国北方吉林、黑龙江、内蒙古(东北部)三省区的流行、分布、危害程度等情况,在本调查中,以富有代表性的12个梅花鹿场共1014份血清样品作为研究对象,进行血清学(ELISA)检测,以期进一步为检疫、防疫部门制定防制措施提供科学的理论依据,以确保养鹿业的健康发展。     

Investigation of aberrant positive reactions to serological tests for bovine brucellosis

Fifty cattle thought not to be infected with Brucella abortus but giving persistent positive serological reactions, were investigated. It was concluded that only one of these was infected since exhaustive bacteriological examination produced only one isolate of B. abortus (strain 19) and none of the herds of origin was subsequently shown to be infected with brucellosis. Antibody was detected in stifle joint fluid of 15 cattle, which may have been stimulated by the presence of Strain 19 antigen that persisted in collagenous tissue long after the viable organisms had been eliminated.     

Bayesian estimation of the true prevalence,sensitivity and specificity of the Rose Bengal and indirect ELISA tests in the diagnosis of bovine brucellosis

Serology is the most convenient method for detecting brucellosis but the efficient use of such tests in disease control requires evaluation of diagnostic performance and discriminative ability. The objective of this study was to assess the performance of the Rose Bengal test (RBT) and an indirect ELISA (iELISA) in diagnosing brucellosis in 995 serum samples collected from cattle in the Ivory Coast between 2005 and 2009. A Bayesian approach was used to evaluate the two tests by estimating their sensitivities and specificities.The correlation-adjusted sensitivity of the iELISA was estimated to be 96.1% (credibility interval [CrI], 92.7–99.8), whereas that of the RBT was 54.9% (CrI, 23.5–95.1). High correlation-adjusted specificities were found for both tests (95.0%; [CrI, 91.1–99.6] for the iELISA and 97.7%; [CrI, 95.3–99.4] for the RBT, respectively). The true prevalence of brucellosis was estimated from the serum samples to be 4.6% (95%; [CrI, 0.6–9.5]). The level of agreement between the two tests was evaluated using indices of agreement (n = 995). Good agreement was found for negative results (96.6%; confidence interval [CI], 95.7–97.4), a finding supported by an estimated significant correlation of 0.37 (95%; CI, 0.01–0.73) within the sera testing negative. Agreement was lower for sera testing positive (52.2% CI: 41.9–62.5). The findings highlight the importance of using these two tests in combination as part of any brucellosis control programme.     

Validation of enzyme-linked immunosorbent assays for the diagnosis of bovine brucellosis

The purpose of this study was to evaluate the performance of the indirect enzyme immunoassay (IELISA) and the competitive enzyme immunoassay (CELISA) for the diagnosis of bovine brucellosis in comparison to conventional serological tests routinely used in Argentina. Serum samples (n = 3500), from Brucella-free herds, from vaccinated cattle and from naturally infected cattle, were tested by the following tests: buffered antigen agglutination test (BPAT), rose bengal test (RBT), 2-mercaptoethanol test (2-ME), complement fixation test (CFT), IELISA and CELISA. Sensitivity and specificity of the BPAT, RBT, IELISA and CELISA were determined relative to the 2-ME and the CFT. The CELISA was considered suitable for eliminating most serological reactions of vaccinated animals and was more specific than the other tests. The results indicate the potential use of the CELISA as a complementary assay in the brucellosis control and eradication program in Argentina and other countries, where Brucella abortusstrain 19 vaccination is mandatory.     

不同的血清学方法对布病疫苗免疫绵羊抗体检测结果的比较研究

将国内广泛用于预防羊布病的S2和M5疫苗免疫绵羊,然后定期采血进行细菌分离和血清学检测,并比较血清学方法的检测结果。结果表明ELISA操作方便,具有较好的敏感性和特异性,建议在检疫中用敏感性较高的RBT初筛,用特异性较好的ELISA确诊,以得到较好的效果。