Field Trial of a Brucellosis Competitive Enzyme Linked Immunoabsorbent Assay (Elisa) (original) (raw)
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Evaluation of serological diagnostic tests of human brucellosis for prevention and control in Mexico
European Journal of Clinical Microbiology & Infectious Diseases, 2020
Brucellosis is a zoonosis mainly present in developing countries. The WHO reports 500,000 new cases every year. From 2012 to 2016, 13,677 cases were reported in Mexico, with 2.00 to 2.64 rate per 100,000 inhabitants. To analyze the diagnostic algorithm of brucellosis in Mexico, we compared the commercial laboratory tests ELISA, Brucellacapt®, and lateral flow test (LFT) in a study of 473 individuals from two endemic Mexican populations. All patients were treated in first-level medical units for presenting brucellosis compatible symptoms and without a history of the disease. Clinical-epidemiological information was gathered and initial serum samples were obtained to react with anti-Brucella antibodies; subsequent samples were collected at follow-up treatment visits. Using the Rose Bengal screening, we found 165 negative samples and 308 positive reactive samples, of which 222 cases were confirmed and 234 were positive on at least one marker (IgG or IgM) or LFT. When Brucellacapt® was used, similar results to those observed with the conventional algorithm were found as judged by the Cohen's kappa coefficient (κ) (0.813, 95% CI 0.7788-0.8472). Similar κ indices between conventional algorithm and ELISA pair were found, 0.7038 (95% CI 0.6555-0.7521), representing high similarity between both groups of diagnosis. We conclude that conventional serodiagnoses, Brucellacapt® and LFT, presented inconclusive results and poor correlation between them. By contrast, ELISA test pair (IgG + IgM) presented high correlation with the conventional algorithm and greater capacity for correct positive and negative classification.
Preventive Veterinary Medicine, 2012
While serological tests are essential in surveillance and control programs of animal diseases, to date none of the common serological tests approved in the EU (complement fixation test or Rose-Bengal test) has been shown to be reliable in routine individual diagnosis of porcine brucellosis, and some more recent tests like ELISA have not been fully evaluated yet. In the absence of a gold standard, this study allowed the estimation of sensitivities and specificities of these tests with a Bayesian approach using Markov Chain Monte Carlo algorithms.
International Journal of One Health, 2018
Background: In Uganda, detection of brucellosis in goats and humans is more frequently done using rose bengal plate test (RBPT) in comparison to other serological tests such as serum agglutination test (SAT) and indirect enzyme-linked immunosorbent assay (i-ELISA). Aim: This study aimed at estimating the degree of agreement, specificity and sensitivity of RBPT, SAT, and ELISA in brucellosis detection in human and goat samples. Materials and Methods: An analytical study was conducted involving parallel testing of 425 goat samples and 177 human samples to compare RBPT, SAT, and i-ELISA tests of brucellosis detection. Results: A seroprevalence of 14.82% in animals and 11.86% in humans was detected using RBPT, 7.06% in goats and 5.09% in humans using SAT, and 6.35% in humans and 4.52% in animals using i-ELISA. The degree of agreement between the three tests in humans and animals was compared using Fleiss' kappa statistics where a moderate agreement (MA) was obtained for both with kappa value 0.57 in animals and 0.51 in humans and p<0.001. Kappa values in animals were 0.52 (MA) for RBPT and i-ELISA, 0.61 (MA) for RBPT and SAT, and 0.82 substantial agreement (SA) for SAT and i-ELISA. The kappa values in humans were 0.52 (MA) for RBPT and i-ELISA, 0.57 (MA) for RBPT and SAT, and 0.82 (SA) for SAT and i-ELISA, respectively. The study revealed a significant agreement in the tests for all the three tests, but there was SA between SAT and i-ELISA in both animal and human samples. Sensitivity and specificity of RBT and SAT were estimated using i-ELISA as a gold standard as follows, in goats RBPT: 100 and 91% and SAT: 100 and 99%, respectively, and in humans RBPT: 100 and 92% and SAT: 88 and 99%, respectively. Conclusion: It appears that RBPT is good as a screening test, whereas SAT and i-ELISA are good for diagnosis purposes or confirmatory test.
Frontiers in Veterinary Science, 2020
Bovine brucellosis has been under eradication in Uruguay since 1998. The eradication program includes, among other interventions, individual sera sampling of beef animals at slaughter, and annual serum testing of all dairy cows-accounting for two million samples annually. At a herd prevalence of 0.8%, a pooled-sera sample approach could reduce the economic burden of the surveillance system by reducing the testing and operational costs. Our objective was to evaluate the analytic sensitivity of an indirect ELISA test for Brucella abortus in serum pools. Sixty-two Brucella abortus-positive bovine sera samples (based upon rose bengal and fluorescent polarization assay) were used as the positive control samples. Rose bengal-negative sera from negative farms were used to dilute the positive samples to the desired concentrations. Positive samples were diluted by using 1 ml of positive sera and 1 ml of negative sera (1/2 dilution) up to 1/1,024. Data were analyzed using generalized linear mixed models with a binary outcome (positive or negative), dilution number as a fixed effect, and a random effect for sample ID. Analytic sensitivity was 99.0% [95% confidence interval (CI): 96.3-99.7], 98.3% (95% CI: 93.1-99.6), 97.3% (95% CI: 87.4-99.4) for dilutions 1/2, 1/4, and 1/8, respectively. The analytical sensitivity, however, decreased when diluted to greater proportions. Given the current herd prevalence in Uruguay, it seems plausible that the use of a pooled sample approach could be adopted by policymakers to reduce the cost of the surveillance program and increase the number of samples being tested.
Validation of non-commercial indirect ELISA techniques in the diagnosis of bovine brucellosis
Alexandria Journal of Veterinary Sciences, 2017
Ninety one blood samples were collected from unvaccinated cattle with a history of Brucella melitensis biovar 3 infection and belonged to the Nile Delta region during slaughter in abattoirs. Serum samples were separated and sample size were estimated according to OIE requirements (2% errors and 95% confidence interval) for the validation of two developed indirect enzyme linked immunosorbent assay (iELISA) techniques using different antigens namely lipopolysaccharide antigen (LPS) and soluble periplasmic protein antigen (PPP) against an iELISA (LPS) commercial kit. Diagnostic performance characteristics were estimated considering complement fixation test (CFT) as the gold standard. The estimated relative sensitivities (Se) and specificities (Sp) of the three iELISA versions were as follows: iELISA (PPP) (88% and 94%), iELISA (LPS) (92% and 87%) commercial kit and home-made iELISA (LPS) (90% and 84%). The estimated κ agreement values with the CFT indicated substantial agreement in case of iELISA versions used both LPS and PPP antigens. The performance of iELISA based on both ROCs and AUCs was very good being equal to or closer to 0.9. Performance indices (PI) values were charted in ascending order. The accuracy % was calculated to be 90% for both iELISA (PPP) and iELISA (LPS) kit and 88% for home-made iELISA (LPS). Highest positive predictive values were achieved by iELISA (PPP), while the highest negative predictive values were achieved by iELISA (LPS) standard kit. The highest positive likelihood ratio (LR+) was attained by iELISA (PPP), while the negative likelihood ratio (LR-) was almost the same. Authors suggest that the home-made iELISA (LPS) is fit for its purpose as a rapid screening test. The high performance characteristics of iELISA (PPP), especially the balance of both Se and Sp, necessitates a reclassification of this version as confirmatory rather than screening test with further studies.
Enzyme immunoassays for serological diagnosis of bovine brucellosis: a trial in Latin America
Clinical and Vaccine …, 1998
ENZYME IMMUNOASSAYS FOR THE DIAGNOSIS OF BOVINE BRUCELLOSIS: TRIAL IN LATIN AMERICA. The results of a field trail conducted in Latin America with two indirect (IELISA) and two competitive (CELISA) enzyme immunoassays for the detection of bovine antibody to Brucella abortus are reported. One of the CELISA formats performed most accurately. The relative sensitivity of this assay was 97.47%, the relative specificity for unexposed cattle was 98.32% and the specificity in cattle vaccinated with Brucella abortus strain 19 was 96.51%. The same assay format under Canadian conditions had a sensitivity of 100%, a specificity of 99.90% and a specificity of 97.7% in a strain 19 vaccinated population. Overall, the CELISA performed as expected and the results were not dissimilar to the results obtained in the Canadian study thus providing further evidence that this CELISA can in many instances differentiate infected cattle from those that are vaccinated or infected with a cross-reacting organism while still giving very low false positive or false negative results. 1.
Evaluation of ELISA and Brucellacapt tests for diagnosis of human Brucellosis
Iranian journal of microbiology, 2013
Brucellosis is one of the most common zoonotic diseases in Iran and human brucellosis is endemic in all parts of the country. Because of the difficulty in the diagnosis of brucellosis, particularly in endemic areas, the use of new and feasible diagnostic tests seem to be of great importance for resolving the diagnostic obstacles. We evaluated the usefulness of a new serological test based on an immunocapture-agglutination technique in comparison with ELISA test for serological diagnosis of brucellosis. A total of 11 patients with brucellosis, who had positive blood cultures for Brucella species, and 47 suspected patients were included in this study. Serum samples collected from these patients were tested by brucellacapt and ELISA and the results were, consequently, compared. In patients with positive blood culture, all the samples gave positive results with brucellacapt test while IgM ELISA, IgG ELISA and (IgG + IgM) ELISA tests were positive in 8, 9 and 11 patients, respectively. O...
Seroprevalence of Bovine Brucellosis Using Indirect Elisa in Quetta Balochistan, Pakistan
Journal of Animal and Plant Sciences, 2012
Brucellosis is considered the most important zoonosis worldwide with high prevalence among livestock. A total of 780 cattle (n = 405) and buffalo (n = 375) serum samples were collected from abattoirQuetta, Balochistan and evaluated for the presence of antibrucella antibodies, using Rose Bengal plate test (RBPT) and indirect enzyme -linked immunosorbent assay (i-ELISA) respectively. The overall prevalence of 3 % and 3.20 % was recorded through RBPT and i -ELISA respectively.In samples collected from cattle (n=405) the higher seroprevalence of 3.95 % and 5.9 % was recorded than buffaloes (n= 375) with 2.1% and 0.265 using RBPT and i -ELISA respectively. Similarly a relatively higher seroprevalence offoundin female animals as 3.72 % and 3.88 % using RBPT and ELlSA respectively. While the prevalence in male was 0.6% using both the test. These results revealed that RBPT and ELISA can be used for large scale screening of brucella antibodes in animals. These fi ndings suggest an alarming s...