Parameter estimation and use of gamma interferon assay for the diagnosis of bovine tuberculosis in Brazil

Lopes, Luciano Bastos; Alves, Telma Maria; Stynen, Ana Paula Reinato; Mota, Pedro; Leite, Rômulo Cerqueira; Lage, Andrey Pereira

doi:10.1590/s0100-736x2012000400001

Cited by 6 publications

(4 citation statements)

References 18 publications

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“…Both tests were very specific, with small variations between herds and within herds. Also, specificities estimates were close to those already reported in the literature (Lopes et al, 2012;Casal et al, 2014).…”

Section: Discussionsupporting

confidence: 88%

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Diagnostic performance of a commercial ELISA used as a complementary test for bovine tuberculosis in two bovine herds with different disease status

Filho

Ramalho

Silva

et al. 2020

Arq. Bras. Med. Vet. Zootec.

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Bovine tuberculosis is a worldwide spread zoonotic disease. Intradermal tuberculinizations are the most used diagnostic tests in the world. Serological tests can be an ancillary diagnosis for bovine tuberculosis. The objective of this study was to evaluate the diagnostic performance of the ELISA Mycobacterium Bovis Antibody Test Kit IDEXX ™ in infected herds, which were in different disease control stages. One hundred and twenty animals from two dairy herds of Minas Gerais state, Brazil, were subjected to the ELISA serological test and the comparative cervical tuberculin test (CCT). Diagnostic test parameters were estimated using Bayesian latent class models and concordance between tests estimated by the frequentist approach. The ELISA test presented lower sensitivity than CCT in both herds. Its sensitivity was higher in the herd in sanitation process. Specificity estimates were above 95% in both herds. Kappa index indicated low concordance or even disagreement between tests. According to the results, the ELISA IDEXX should not be used as substitution for CCT. The tests must not be associated in series. Parallel association increased diagnostic sensitivity in the herd which was in the process of sanitation.

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Section: Discussionsupporting

confidence: 88%

“…Bayesian latent class models had already been used before to evaluate diagnostic tests for bovine tuberculosis (Álvarez et al, 2012;Lopes et al, 2012). However, it had never been done before for this commercial serological test, aimed to diagnose bovine tuberculosis in Brazil using BLCA.…”

Section: Discussionmentioning

confidence: 99%

Diagnostic performance of a commercial ELISA used as a complementary test for bovine tuberculosis in two bovine herds with different disease status

Filho

Ramalho

Silva

et al. 2020

Arq. Bras. Med. Vet. Zootec.

View full text Add to dashboard Cite

show abstract

“…In a study conducted in Brazil, kappa values were 0.54-0.66 depending on time points when the IFN-γ assay (Bovigam, criteria for the IFN-γ assay not provided) was performed. Agreement increased to 0.649-0.713 when data from cattle affected by M. avium complex were withdrawn (23). A study performed in Ireland in 2015 showed relatively higher agreement between the single intradermal comparative tuberculin test and IFN-γ assay (Bovigam, cutoff for the INF-γ assay = 0.05) (20).…”

Section: Discussionmentioning

confidence: 99%

Introduction and Application of the Interferon-γ Assay in the National Bovine Tuberculosis Control Program in South Korea

et al. 2020

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Bovine tuberculosis is a chronic disease impacting both public health and the livestock industry. The interferon (IFN)-γ assay has been introduced as an ancillary test for diagnosing bovine tuberculosis to overcome limitations of the skin test. The objective of this study was to assess the IFN-γ assay in terms of diagnostics and as a nationwide surveillance program in South Korea. From 2012 to 2013, cattle (n = 120) with bovine tuberculosis and cattle (n = 426) from bovine tuberculosis free herds were subjected to the IFN-γ assay to evaluate the sensitivity and specificity of the assay, respectively, depending on various cutoffs (0-3.5). When optical density of the cutoff was 0.1, the sensitivity and specificity were found to be 81.7% (74.7-88.6) and 99.5% (98.9-100.0), respectively. After introducing the IFN-γ assay as part of the national control program, the IFN-γ assay and single caudal fold skin test data were collected from 47 regional veterinary services to compare the results of these two tests. Overall, the agreement between the IFN-γ assay and the single caudal fold skin test (n = 492,068) was 98.2%, and Cohen's kappa value for the two methods was 0.47. Serial and parallel use of the IFN-γ assay and skin test for the bovine tuberculosis control program were compared using samples (n = 91) from cattle confirmed as bovine tuberculosis positive in laboratories from 2014 to 2016. Parallel screening for bTB showed much higher sensitivity (86/91, 94.5%) than the following screening approaches: serial (47.2%, 43/91), single screening using CFT (63.7%, 58/91), or the IFN-γ assay (78.0%, 71/91). These results indicate that the IFN-γ assay and single caudal fold skin test are complementary to each other; therefore, parallel use of these two tests is considered a useful approach to reduce the prevalence of bovine tuberculosis in South Korea.

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“…A longer storage or transportation of the blood samples might lead to a decrease in the mean OD or the IFN-ɣ production [ 73 – 75 ]. With regard to the sensitivity and specificity of the Bovigam® assay several studies state that blood could also be processed 24 h later without statistical significant changes [ 76 , 77 ]. However, Laboratory 3 reached also only a substantial agreement of 0.62 between the Bovigam® assay test results of the V .…”

Section: Discussionmentioning

confidence: 99%

Evaluating diagnostic tests for bovine tuberculosis in the southern part of Germany: A latent class analysis

et al. 2017

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Germany has been officially free of bovine tuberculosis since 1996. However, in the last years there has been an increase of bovine tuberculosis cases, particularly in the southern part of Germany, in the Allgäu region. As a consequence a one-time tuberculosis surveillance program was revisited with different premortal and postmortal tests. The aim of this paper was to estimate diagnostic sensitivities and specificities of the different tests used within this surveillance program. In the absence of a perfect test with 100% sensitivity and 100% specificity, thus in the absence of a gold standard, a Bayesian latent class approach with two different datasets was performed. The first dataset included 389 animals, tested with single intra-dermal comparative cervical tuberculin (SICCT) test, PCR and pathology; the second dataset contained 175 animals, tested with single intra-dermal cervical tuberculin (SICT) test, Bovigam® assay, pathology and culture. Two-way conditional dependencies were considered within the models. Additionally, inter-laboratory agreement (five officially approved laboratories) of the Bovigam® assay was assessed with Cohen's kappa test (21 blood samples). The results are given in posterior means and 95% credibility intervals. The specificities of the SICT test, SICCT test, PCR and pathology ranged between 75.8% [68.8–82.2%] and 99.0% [96.8–100%]. The Bovigam® assay stood out with a very low specificity (6.9% [3.6–11.1%]), though it had the highest sensitivity (95.7% [91.3–99.2%]). The sensitivities of the SICCT test, PCR, SICT test, pathology and culture varied from 57.8% [48.0–67.6%] to 88.9% [65.5–99.7%]. The prevalences were 19.8% [14.6–26.5%] (three-test dataset) and 7.7% [4.2–12.3%] (four-test dataset). Among all pairwise comparisons the highest agreement was 0.62 [0.15–1]). In conclusion, the specificity of the Bovigam® assay and the inter-laboratory agreement were lower than expected.

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Parameter estimation and use of gamma interferon assay for the diagnosis of bovine tuberculosis in Brazil

Cited by 6 publications

References 18 publications

Diagnostic performance of a commercial ELISA used as a complementary test for bovine tuberculosis in two bovine herds with different disease status

Diagnostic performance of a commercial ELISA used as a complementary test for bovine tuberculosis in two bovine herds with different disease status

Introduction and Application of the Interferon-γ Assay in the National Bovine Tuberculosis Control Program in South Korea

Evaluating diagnostic tests for bovine tuberculosis in the southern part of Germany: A latent class analysis

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