Assessment of serological tests for diagnosis of bovine tuberculosis

McCallan, Lyanne; Brooks, C.; Couzens, Catherine; Young, Fiona; McNair, J.; Byrne, Andrew

doi:10.1136/vr.104272

Cited by 17 publications

(14 citation statements)

References 14 publications

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“…A number of factors have contributed to this failure to eradicate (Skuce et al 2012), including the presence of a wildlife reservoir of infection (the European badger, Meles meles; Griffin et al 2005;Byrne et al 2014). Compounding this problem is the fact that tests used to identify infected cattle exhibit nonperfect test characteristics (De la Rua-Domenech et al 2006;McCallan et al 2017;Lahuerta-Marin et al 2018). For example, the Single Intradermal Comparative Tuberculin Test (SICTT), the standard test used in the United Kingdom and ROI exhibits high mean specificity (>99%; de la Rua- Domenech et al 2006;Clegg et al 2011;Lahuerta et al, 2018), but moderate mean sensitivity (50%-80%; De la Rua-Domenech et al, 2006;Clegg et al 2011;Nuñez-Garcia et al 2018;Lahuerta et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Liver fluke (Fasciola hepatica) co‐infection with bovine tuberculosis (bTB) in cattle: A retrospective animal‐level assessment of bTB risk in dairy and beef cattle

Byrne

McBride

Graham

et al. 2018

Transbound Emerg Dis

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Bovine tuberculosis (bTB), caused by Mycobacterium bovis, remains a persistent problem for cattle industries in endemic countries. The frequency, quality, and performance of tests, and the presence of wildlife reservoirs, have been identified as impediments to eradication. Recently, exposure to helminth infection (Fasciola hepatica) has been associated negatively with the disclosure of bTB. Here, for the first time, we assess impact of concurrent infections of Fasciola hepatica and the disclosure of bTB at the animal‐level using large surveillance datasets. We utilized a dataset of 138,566 animal records from an abattoir from Northern Ireland (2011–2013). The presence of F. hepatica infection was assessed from macroscopic tissue inspection at abattoir. Multivariable models were developed to assess co‐infection associations with bTB status based on: Single Intradermal Comparative Tuberculin Test (SICTT), lesion, bacteriological confirmation, including either all animals, or only skin‐test negative animals (lesions at routine slaughter; LRS; confirmed nonreactors at routine slaughter; cNRs) or positive (reactors) animals alone, respectively. The relationship between skin tuberculin reaction sizes and fluke status was also explored for a subset of animals with field recordings (n = 24,680). Controlling for known risk factors (e.g., climatic, herd, and individual level characteristics), we did not find significant associations between the SICTT (standard or severe interpretation), lesion, nor confirmation status of animals and their liver fluke status. The only exception was a negative association between liver fluke positivity, and LRS or cNRs, respectively; though effect‐sizes were small (e.g., LRS Odds‐Ratio: 0.87; 95% CI: 0.76–1.00). There was limited evidence of a relationship between tuberculin reaction sizes during SICTT testing and liver fluke infection status. These data do not support the contention that the detection of bTB using skin‐tests or reactor postmortem follow‐up may be compromised by co‐infection at a population level, but the relationship with lesion formation (pathogenesis) may indicate an impact for postmortem surveillance.

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Section: Introductionmentioning

confidence: 99%

Liver fluke (Fasciola hepatica) co‐infection with bovine tuberculosis (bTB) in cattle: A retrospective animal‐level assessment of bTB risk in dairy and beef cattle

Byrne

McBride

Graham

et al. 2018

Transbound Emerg Dis

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“…In the current study, a small proportion of animals were disclosed as serology positive (mean 3% positive). However, during another study in Northern Ireland, we found a higher proportion of animals were disclosed as positive when prevalence was higher (86% SICCT test reactors) and testing occurred after skin testing (14). The proportion serology positive in that cohort was 39.0262.20% positive, with apparent sensitivities relative to post-mortem confirmed infection estimated to be 68-82%.…”

Section: Discussionmentioning

confidence: 63%

“…In comparison with previous work by our group (14), serology samples were taken prior to the SICCT tuberculin test. In work from Spain, when serology tests were evaluated prior to the tuberculin test, their performance was reduced relative to tests undertaken with samples after the tuberculin test (27).…”

Section: Discussionmentioning

confidence: 99%

“…The epidemiology of disease is complicated by the presence of infection in wildlife (6, 7), and the potential confounding effects of concurrent infections (8, 9, 10). Current diagnostic tests applied to cattle are not sufficiently sensitive to identify all infected animals and to remove them before infection is spread (11-14). This is despite the introduction and widespread use of the interferon gamma release assay (IFNγ; 15) to augment the bovine TB testing regime and to support the front line tests (16).…”

Section: Introductionmentioning

confidence: 99%

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Performance of serological antibody tests for bovine tuberculosis in cattle from infected herds in Northern Ireland

McCallan

Brooks

Couzens

et al. 2017

Preprint

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1The ability to accurately identify infected hosts is the cornerstone of effective disease control 1 2 and eradication programs. In the case of bovine tuberculosis, caused by infection with the 1 3pathogen Mycobacterium bovis, accurately identifying infected individual animals has been 1 4 challenging as all available tests exhibit less than 100% discriminatory ability. Here we 1 5 assess the utility of three serological tests and assess their performance relative to skin test where one test was used in conjunction with statutory testing. 9Serological tests using samples taken prior to SICCT disclosed low proportions of animals as with TB visible lesions (27%) or with laboratory confirmed infection (25%). As a result, 2 4 apparent sensitivities within this cohort was very low (≤15%), however the tests succeeded in 2 5 achieving very high specificities (96-100%). During the case-study, 7/670 (1.04%) samples 2 6 from SICCT negative animals from a large chronically infected herd were serology positive, 2 7 with a further 10 animals being borderline positive (17/670; 2.54%). 9/17 of these animals 2 8were voluntarily removed, none of which were found to be infected (-lesions/-bacteriology) 2 9 post-mortem; 1 serology test negative animal was subsequently lesion+ and M. bovis 3 0 confirmed at slaughter.

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“…The standard interpretation of the SICCT test has been estimated to have a sensitivity of approximately 50%–80% and specificity of >99.9% in the UK (De la Rua‐Domenech et al., ; Goodchild, Downs, Upton, Wood, & De la Rua‐Domenech, ; Lahuerta‐Marin et al., ), while the ancillary gamma interferon test has a higher estimated sensitivity (~80%–90%) at the cost of lower specificity (83%–97% [Lahuerta‐Marin et al., ]). Serological tests have also been shown to have variable apparent sensitivity and specificity, depending on the epidemiological context (McCallan et al., ). The performance of such tests, based on immunological response to the pathogen exposure, can be impacted by a number of individual animal characteristics (Downs, Broughan, Goodchild, Upton, & Durr, ).…”

Section: Introductionmentioning

confidence: 99%

Modelling the variation in skin-test tuberculin reactions, post-mortem lesion counts and case pathology in tuberculosis-exposed cattle: Effects of animal characteristics, histories and co-infection

Byrne

Graham

Brown

et al. 2018

Transbound Emerg Dis

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Correctly identifying bovine tuberculosis (bTB) in cattle remains a significant problem in endemic countries. We hypothesized that animal characteristics (sex, age, breed), histories (herd effects, testing, movement) and potential exposure to other pathogens (co-infection; BVDV, liver fluke and Mycobacterium avium reactors) could significantly impact the immune responsiveness detected at skin testing and the variation in post-mortem pathology (confirmation) in bTB-exposed cattle. Three model suites were developed using a retrospective observational data set of 5,698 cattle culled during herd breakdowns in Northern Ireland. A linear regression model suggested that antemortem tuberculin reaction size (difference in purified protein derivative avium [PPDa] and bovine [PPDb] reactions) was significantly positively associated with post-mortem maximum lesion size and the number of lesions found. This indicated that reaction size could be considered a predictor of both the extent (number of lesions/tissues) and the pathological progression of infection (maximum lesion size). Tuberculin reaction size was related to age class, and younger animals (<2.85 years) displayed larger reaction sizes than older animals. Tuberculin reaction size was also associated with breed and animal movement and increased with the time between the penultimate and disclosing tests. A negative binomial random-effects model indicated a significant increase in lesion counts for animals with M. avium reactions (PPDb-PPDa < 0) relative to non-reactors (PPDb-PPDa = 0). Lesion counts were significantly increased in animals with previous positive severe interpretation skin-test results. Animals with increased movement histories, young animals and non-dairy breed animals also had significantly increased lesion counts. Animals from herds that had BVDV-positive cattle had significantly lower lesion counts than animals from herds without evidence of BVDV infection. Restricting the data set to only animals with a bTB visible lesion at slaughter (n = 2471), an ordinal regression model indicated that liver fluke-infected animals disclosed smaller lesions, relative to liver fluke-negative animals, and larger lesions were disclosed in animals with increased movement histories.

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Assessment of serological tests for diagnosis of bovine tuberculosis

Cited by 17 publications

References 14 publications

Liver fluke (Fasciola hepatica) co‐infection with bovine tuberculosis (bTB) in cattle: A retrospective animal‐level assessment of bTB risk in dairy and beef cattle

Liver fluke (Fasciola hepatica) co‐infection with bovine tuberculosis (bTB) in cattle: A retrospective animal‐level assessment of bTB risk in dairy and beef cattle

Performance of serological antibody tests for bovine tuberculosis in cattle from infected herds in Northern Ireland

Modelling the variation in skin-test tuberculin reactions, post-mortem lesion counts and case pathology in tuberculosis-exposed cattle: Effects of animal characteristics, histories and co-infection

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