Bovine tuberculosis visible lesions in cattle culled during herd breakdowns: the effects of individual characteristics, trade movement and co-infection

dc.contributor.authorByrne, Andrew W.
dc.contributor.authorGraham, Jordon
dc.contributor.authorBrown, Craig
dc.contributor.authorDonaghy, Aoibheann
dc.contributor.authorGuelbenzu Gonzalo, Maria
dc.contributor.authorMcNair, James
dc.contributor.authorSkuce, Robin A.
dc.contributor.authorAllen, Adrian
dc.contributor.authorMcDowell, Stanley W.J.
dc.descriptionPublication history: Accepted - 14 December 2017; Published online - 29 December 2017.en_US
dc.description.abstractBackground: Bovine tuberculosis (bTB), caused by Mycobacterium bovis, remains a significant problem for livestock industries in many countries worldwide including Northern Ireland, where a test and slaughter regime has utilised the Single Intradermal Comparative Cervical Tuberculin (SICCT) test since 1959. We investigated the variation in post-mortem confirmation based on bTB visible lesion (VL) presence during herd breakdowns using two model suites. We investigated animal-level characteristics, while controlling for herd-level factors and clustering. We were interested in potential impacts of concurrent infection, and therefore we assessed whether animals with evidence of liver fluke infection (Fasciola hepatica; post-mortem inspection), M. avium reactors (animals with negative M. bovis-avium (b-a) tuberculin reactions) or Bovine Viral Diarrhoea Virus (BVDV; RT-PCR tested) were associated with bTB confirmation. Results: The dataset included 6242 animals removed during the 14 month study period (2013–2015). bTB-VL presence was significantly increased in animals with greater b-a reaction size at the disclosing SICCT test (e.g. b-a = 5- 9 mm vs. b-a = 0 mm, adjusted Odds ratio (aOR): 14.57; p < 0.001). M. avium reactor animals (b-a < 0) were also significantly more likely to disclose VL than non-reactor animals (b-a = 0; aOR: 2.29; p = 0.023). Animals had a greater probability of exhibiting lesions with the increasing number of herds it had resided within (movement; logherds: aOR: 2.27–2.42; p < 0.001), if it had an inconclusive penultimate test result (aOR: 2.84–3.89; p < 0.001), and with increasing time between tests (log-time; aOR: 1.23; p = 0.003). Animals were less likely to have VL if they were a dairy breed (aOR: 0.79; p = 0.015) or in an older age-class (e.g. age-quartile 2 vs. 4; aOR: 0.65; p < 0.001). Liver fluke or BVDV variables were not retained in either multivariable model as they were non-significantly associated with bTB-VL status (p > 0.1). Conclusions: Our results suggest that neither co-infection of liver fluke nor BVDV had a significant effect on the presence of VLs in this high-risk cohort. M. avium tuberculin reactors had a significantly increased risk of disclosing with a bTB lesion, which could be related to the impact of co-infection with M. avium subsp. paratuberculosis (MAP) affecting the performance of the SICCT however further research in this area is required. Movements, test history, breed and age were important factors influencing confirmation in high-risk animals.en_US
dc.description.sponsorshipThis work was funded as part of a broader study of concurrent infections and their role in bTB epidemiology in Northern Ireland (48005 (122035): 15/3/10 − bTB Endemic Diseases; PI: Dr. Andrew Byrne) funded under the Evidence and Innovation (E&I) Scheme by the Department of Agriculture and Rural Development (DAERA;
dc.identifier.citationByrne, A. W., Graham, J., Brown, C., Donaghy, A., Guelbenzu-Gonzalo, M., McNair, J., Skuce, R., Allen, A. and McDowell, S. (2017) ‘Bovine tuberculosis visible lesions in cattle culled during herd breakdowns: the effects of individual characteristics, trade movement and co-infection’, BMC Veterinary Research, 13(1). doi: 10.1186/s12917-017-1321-z.en_US
dc.rightsOpen Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.en_US
dc.subjectBovine TBen_US
dc.subjectMycobacterium bovisen_US
dc.subjectLiver flukeen_US
dc.subjectJohne's diseaseen_US
dc.subjectGamma interferonen_US
dc.subjectSkin testsen_US
dc.titleBovine tuberculosis visible lesions in cattle culled during herd breakdowns: the effects of individual characteristics, trade movement and co-infectionen_US
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