The Effect of<i>Mycobacterium avium</i>Complex Infections on Routine<i>Mycobacterium bovis</i>Diagnostic Tests

Barry, Claire; Corbett, David; Bakker, Douwe; Andersen, Peter Henrik; McNair, J.; Strain, Sam

doi:10.4061/2011/145092

Cited by 27 publications

(28 citation statements)

References 30 publications

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“…However, in a study on cattle experimentally infected with MAP, a proportion of animals were misclassified as TB reactors using the IFNγ test at different time points post-infection, including one animal that was misclassified at 44% of the sampling time points [17]. No animals were misclassified by the SICTT.…”

Section: Discussionmentioning

confidence: 99%

Identification of risk factors associated with disclosure of false positive bovine tuberculosis reactors using the gamma-interferon (IFNγ) assay

Gormley

Doyle

Duignan

et al. 2013

Vet Res

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The gamma-interferon assay (IFNγ) is often used as an ancillary diagnostic test alongside the tuberculin skin test in order to detect Mycobacterium bovis infected cattle. The performance of the IFNγ test has been evaluated in many countries worldwide and wider usage as a disease surveillance tool is constrained due to the relatively low and inconsistent specificity at a herd and area level. This results in disclosure of a higher proportion of false positive reactors when compared with the skin test. In this study, we used cohorts of animals from low prevalence tuberculosis herds (n = 136) to assess a range of risk factors that might influence the specificity of the test. Univariate and multivariate logistic generalised estimating-equation (GEE) models were used to evaluate potential risk factors associated with a false positive IFNγ test result. In these herds, the univariate model revealed that the region of herd origin, the time of year when the testing was carried out, and the age of the animal were all significant risk factors. In the final multivariate models only animal age and region of herd origin were found to be significant risk factors. A high proportion of herds with multiple IFNγ false positive animals were located in one county, with evidence of within-herd clustering, suggesting a localised source of non-specific sensitization. Knowledge of the underlying factors influencing the IFNγ test specificity could be used to optimize the test performance in different disease level scenarios in order to reduce the disclosure rate of false positive reactors.

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Section: Discussionmentioning

confidence: 99%

Identification of risk factors associated with disclosure of false positive bovine tuberculosis reactors using the gamma-interferon (IFNγ) assay

Gormley

Doyle

Duignan

et al. 2013

Vet Res

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“…Whole blood IFN-γ release assay was performed as previously described [31]. Briefly heparinised whole blood was stimulated within one hour of sampling with either PBS (control), avian-purified protein derivatives (PPD-A) at 4 μg/mL final concentration (Veterinary Laboratories Agency, Guildford, UK), bovine-purified protein derivative (PPD-B) at 8 μg/mL final concentration (Veterinary Laboratories Agency, UK), and Johnin-purified protein derivative (PPD-J) at 4 μg/mL final concentration (Central Veterinary Institute, Copenhagen,Denmark), pokeweed mitogen (Sigma) (positive control) and a set of peptides (Pool J) spanning MAPK_1565 (C-term) plus MAP K_2533 (N-term) region of the HAV transcript (GK RHTQAVLALARRR; QAVLALARRRLNVLW; LARRRL NVLWAMLRD; LNVLWAMLRDHAVYH; AMLRDHA VYHPATTT; HAVYHPATTTAAARL; SIVGQTYRE VEVVLD; TYREVEVVLVDGGST; EVVLVDGGSTDRT LD; DGGSTDRTLDIANSF) at a final concentration of 2 μg/mL each [23].…”

Section: Whole Blood Ifn-γ Release Assaymentioning

confidence: 99%

Immunity, safety and protection of an Adenovirus 5 prime - Modified Vaccinia virus Ankara boost subunit vaccine against Mycobacterium avium subspecies paratuberculosis infection in calves

Bull

Vrettou

Linedale

et al. 2014

Vet Res

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Vaccination is the most cost effective control measure for Johne's disease caused by Mycobacterium avium subspecies paratuberculosis (MAP) but currently available whole cell killed formulations have limited efficacy and are incompatible with the diagnosis of bovine tuberculosis by tuberculin skin test. We have evaluated the utility of a viral delivery regimen of non-replicative human Adenovirus 5 and Modified Vaccinia virus Ankara recombinant for early entry MAP specific antigens (HAV) to show protection against challenge in a calf model and extensively screened for differential immunological markers associated with protection. We have shown that HAV vaccination was well tolerated, could be detected using a differentiation of infected and vaccinated animals (DIVA) test, showed no cross-reactivity with tuberculin and provided a degree of protection against challenge evidenced by a lack of faecal shedding in vaccinated animals that persisted throughout the 7 month infection period. Calves given HAV vaccination had significant priming and boosting of MAP derived antigen (PPD-J) specific CD4 + , CD8 + IFN-γ producing T-cell populations and, upon challenge, developed early specific Th17 related immune responses, enhanced IFN-γ responses and retained a high MAP killing capacity in blood. During later phases post MAP challenge, PPD-J antigen specific IFN-γ and Th17 responses in HAV vaccinated animals corresponded with improvements in peripheral bacteraemia. By contrast a lack of IFN-γ, induction of FoxP3+ T cells and increased IL-1β and IL-10 secretion were indicative of progressive infection in Sham vaccinated animals. We conclude that HAV vaccination shows excellent promise as a new tool for improving control of MAP infection in cattle.

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“…ESAT6 and CFP10 have also shown potential to circumvent cross-reactivity that could lead to misclassification [107], which was noticed for example in cattle co-infected with other mycobacteria, when PPD's were used [108]. Potentially these proteins, or other newly discovered immunodominant proteins [109][110][111], are able to differentiate infected from vaccinated animals (DIVA), hence can also be used in Bacillus Calmette-Guérin (BCG) vaccinated populations [105,[112][113][114].…”

Section: Ifn-γ Release Assaysmentioning

confidence: 99%

Facts and dilemmas in diagnosis of tuberculosis in wildlife

Maas¹,

Michel²,

Rutten³

2013

Comparative Immunology, Microbiology and Infectious Diseases

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Mycobacterium bovis, causing bovine tuberculosis (BTB), has been recognized as a global threat at the wildlife-livestock-human interface, a clear "One Health" issue. Several wildlife species have been identified as maintenance hosts. Spillover of infection from these species to livestock or other wildlife species may have economic and conservation implications and infection of humans causes public health concerns, especially in developing countries. Most BTB management strategies rely on BTB testing, which can be performed for a range of purposes, from disease surveillance to diagnosing individual infected animals. New diagnostic assays are being developed for selected wildlife species. This review investigates the most frequent objectives and associated requirements for testing wildlife for tuberculosis at the level of individual animals as well as small and large populations. By aligning those with the available (immunological) ante mortem diagnostic assays, the 2 practical challenges and limitations wildlife managers and researchers are currently faced with are highlighted.

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The Effect ofMycobacterium aviumComplex Infections on RoutineMycobacterium bovisDiagnostic Tests

Cited by 27 publications

References 30 publications

Identification of risk factors associated with disclosure of false positive bovine tuberculosis reactors using the gamma-interferon (IFNγ) assay

Identification of risk factors associated with disclosure of false positive bovine tuberculosis reactors using the gamma-interferon (IFNγ) assay

Immunity, safety and protection of an Adenovirus 5 prime - Modified Vaccinia virus Ankara boost subunit vaccine against Mycobacterium avium subspecies paratuberculosis infection in calves

Facts and dilemmas in diagnosis of tuberculosis in wildlife

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