The distribution of Mycobacterium bovis infection in naturally infected badgers

Corner, L. A.; O’Meara, D.; Costello, Eamon; Lesellier, Sandrine; Gormley, Eamonn

doi:10.1016/j.tvjl.2012.03.013

Cited by 58 publications

(80 citation statements)

References 29 publications

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“…A potential route if badgers and cattle come into close proximity is inhalation of aerosolised droplets; however, infected badgers are also known to shed M. bovis in their urine and faeces [9, 10], which may contaminate the environment. Badgers habitually defecate in clusters of shallow pits known as latrines which if accessible to cattle may act as a possible source of infection [11].…”

Section: Introductionmentioning

confidence: 99%

“…Since it is known that some infected badgers excrete M. bovis in their faeces [9, 10], we proposed the development of an immunochromatographic lateral flow device (LFD) and its use in combination with an existing immunomagnetic separation (IMS) technique [21, 22] as a non-invasive test for the presence of M. bovis . Immunochromatographic assays are easy to use, cheap to produce, and provide a rapid result (within 15 min), so are ideal for field use.…”

Section: Introductionmentioning

confidence: 99%

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Development of a novel immunochromatographic lateral flow assay specific for Mycobacterium bovis cells and its application in combination with immunomagnetic separation to test badger faeces

et al. 2017

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BackgroundThe European badger is an important wildlife reservoir of Mycobacterium bovis implicated in the spread of bovine tuberculosis in the United Kingdom and Ireland. Infected badgers are known to shed M. bovis in their urine and faeces, which may contaminate the environment. To aid bovine tuberculosis control efforts novel diagnostic tests for detecting infected and shedding badgers are needed. We proposed development of a novel, rapid immunochromatographic lateral flow device (LFD) as a non-invasive test to detect M. bovis cells in badger faeces. Its application in combination with immunomagnetic separation (IMS) to detect Mycobacterium bovis cells in badger faeces is reported here.ResultsA novel prototype LFD for M. bovis cells was successfully developed, with unique specificity for M. bovis and a limit of detection 50% (LOD50%) of 1.7 × 104 M. bovis cells/ml. When IMS was employed to selectively capture and concentrate M. bovis cells from badger faeces prior to LFD testing, the LOD50% of the IMS-LFD assay was 2.8 × 105 M. bovis cells/ml faecal homogenate. Faeces samples collected from latrines at badger setts in a region of endemic bovine tuberculosis infection were tested; 78 (18%) of 441 samples tested IMS-LFD assay positive, whereas 140 (32%) tested IMS-qPCR positive (Kappa agreement −0.009 ± 0.044, p = 0.838). Subsequently, when 130 faeces samples from live captured, or captive, badgers of known infection status (on the basis of StatPak, interferon-γ and/or culture results) were tested, the IMS-LFD assay had higher relative diagnostic specificity (Sp 0.926), but poorer relative diagnostic sensitivity (Se 0.081), than IMS-qPCR (Sp 0.706, Se 0.581) and IMS-culture (Sp 0.794, Se 0.436).ConclusionsThe novel IMS-LFD assay, although very specific for M. bovis, has low analytical sensitivity (indicated by the LOD50%) and would only detect badgers shedding high numbers of M. bovis (>104–5 cells/g) in their faeces. The novel LFD would, therefore, have limited value as a non-invasive test for badger TB surveillance purposes but it may have value for alternative veterinary diagnostic applications.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development of a novel immunochromatographic lateral flow assay specific for Mycobacterium bovis cells and its application in combination with immunomagnetic separation to test badger faeces

et al. 2017

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“…Although it is unlikely that culture is a perfect ‘gold standard’, the methodology used in this study is based on an enhanced post mortem technique, currently the most sensitive available. In recent years, a progressive increase in estimated prevalence of M. bovis infection in badgers has been observed, both in Ireland and the UK, attributable to improved sensitivity of detection [3], [4]. Crawshaw et al (2008) [28] reported a 54% sensitivity of a standard post-mortem procedure compared to a more detailed enhanced post mortem technique.…”

Section: Discussionmentioning

confidence: 99%

“…The prevalence of Mycobacterium bovis infection in badgers, based on animals captured as part of culling operations by the national Department of Agriculture, Food and the Marine (DAFM), was estimated recently at 36.3% [3], although this is known to vary substantially between areas where bTB in cattle is problematic [4] or absent [5]. Sustainable progress towards eradication of M. bovis infection in cattle might not be possible in the face of continued spillover of infection from badgers to cattle [2].…”

Section: Introductionmentioning

confidence: 99%

Optimising and Evaluating the Characteristics of a Multiple Antigen ELISA for Detection of Mycobacterium bovis Infection in a Badger Vaccine Field Trial

Aznar

Frankena

et al. 2014

PLoS ONE

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A long-term research programme has been underway in Ireland to evaluate the usefulness of badger vaccination as part of the national bTB (bovine tuberculosis) control strategy. This culminated in a field trial which commenced in county Kilkenny in 2009 to determine the effects of badger vaccination on Mycobacterium bovis transmission in badgers under field conditions. In the present study, we sought to optimise the characteristics of a multiplex chemiluminescent assay for detection of M. bovis infection in live badgers. Our goal was to maximise specificity, and therefore statistical power, during evaluation of the badger vaccine trial data. In addition, we also aimed to explore the effects of vaccination on test characteristics. For the test optimisation, we ran a stepwise logistic regression with analytical weights on the converted Relative Light Units (RLU) obtained from testing blood samples from 215 badgers captured as part of culling operations by the national Department of Agriculture, Food and the Marine (DAFM). The optimised test was applied to two other datasets obtained from two captive badger studies (Study 1 and Study 2), and the sensitivity and specificity of the test was attained separately for vaccinated and non-vaccinated badgers. During optimisation, test sensitivity was maximised (30.77%), while retaining specificity at 99.99%. When the optimised test was then applied to the captive badger studies data, we observed that test characteristics did not vary greatly between vaccinated and non-vaccinated badgers. However, a different time lag between infection and a positive test result was observed in vaccinated and non-vaccinated badgers. We propose that the optimized multiplex immunoassay be used to analyse the vaccine trial data. In relation to the difference in the time lag observed for vaccinated and non-vaccinated badgers, we also present a strategy to enable the test to be used during trial evaluation.

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“…The shedding of M . bovis has already been demonstrated in many species via oro-nasal mucus, sputum, urine, feces and wound discharges, depending on the species [7, 10, 11]. Previous experimental studies using various environmental substrates showed that M .…”

Section: Introductionmentioning

confidence: 99%

Impact of temperature and soil type on Mycobacterium bovis survival in the environment

et al. 2017

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Mycobacterium bovis, the causative agent of the bovine tuberculosis (bTB), mainly affects cattle, its natural reservoir, but also a wide range of domestic and wild mammals. Besides direct transmission via contaminated aerosols, indirect transmission of the M. bovis between wildlife and livestock might occur by inhalation or ingestion of environmental substrates contaminated through infected animal shedding. We monitored the survival of M. bovis in two soil samples chosen for their contrasted physical and-chemical properties (i.e. pH, clay content). The population of M. bovis spiked in sterile soils was enumerated by a culture-based method after 14, 30, 60, 90, 120 and 150 days of incubation at 4°C and 22°C. A qPCR based assay targeting the IS1561’ locus was also performed to monitor M. bovis in both sterile and biotic spiked soils. The analysis of survival profiles using culture-based method showed that M. bovis survived longer at lower temperature (4°C versus 22°C) whereas the impact of soil characteristics on M. bovis persistence was not obvious. Furthermore, qPCR-based assay detected M. bovis for a longer period of time than the culture based method with higher gene copy numbers observed in sterile soils than in biotic ones. Impact of soil type on M. bovis persistence need to be deepened in order to fill the gap of knowledge concerning indirect transmission of the disease.

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The distribution of Mycobacterium bovis infection in naturally infected badgers

Cited by 58 publications

References 29 publications

Development of a novel immunochromatographic lateral flow assay specific for Mycobacterium bovis cells and its application in combination with immunomagnetic separation to test badger faeces

Development of a novel immunochromatographic lateral flow assay specific for Mycobacterium bovis cells and its application in combination with immunomagnetic separation to test badger faeces

Optimising and Evaluating the Characteristics of a Multiple Antigen ELISA for Detection of Mycobacterium bovis Infection in a Badger Vaccine Field Trial

Impact of temperature and soil type on Mycobacterium bovis survival in the environment

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