Browsing by Author "Trimble, Nigel"
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ItemEuropean badger (Meles meles) responses to low-intensity, selective culling: using mark recapture and relatedness data to assess social perturbation(Wiley, 2022-07-28) Allen, Adrian; Milne, Margaret Georgina; McCormick, Charles M.; Collins, Shane; O'Hagan, Maria; Skuce, Robin A.; Trimble, Nigel; Harwook, Roland; Menzies, Fraser; Byrne, Andrew W.Culling the main wildlife host of bovine tuberculosis in Great Britain (GB) and Ireland, the European badger (Meles meles), has been employed in both territories to reduce infections in cattle. In GB, this has been controversial, with results suggesting that culling induces disturbance to badger social structure, facilitating wider disease dissemination. Previous analyses hypothesized that even very low-level, selective culling may cause similar deleterious effects by increasing ranging of individuals and greater mixing between social groups. To assess this hypothesis, a novel, prospective, landscape-scale ‘before-and-after’ Test and Vaccinate or Remove (TVR) study was implemented. Test-positive badgers were culled and test-negative badgers were Bacillus Calmette–Guérin (BCG) vaccinated and released. Mark–recapture metrics of badger ranging and genetic metrics of social group relatedness did not change significantly over the study period. However, selective culling was associated with a localized reduction in social group relatedness in culled groups. Ecological context is important; extrapolation across territories and other disease epidemiological systems (epi-systems) is likely to be challenging. However, we demonstrate that small-scale, selective removal of test-positive badgers was not associated with metrics of increased ranging but was associated with localized changes in social group relatedness. This adds to the evidence base on badger control options for policy makers. ItemGenomic epidemiology of Mycobacterium bovis infection in sympatric badger and cattle populations in Northern Ireland(Microbiology Society, 2023-05-25) Akhmetova, Assel; Guerrero, Jimena; McAdam, Paul; Salvador, Liliana C. M.; Crispell, Joseph; Lavery, John; Presho, Eleanor; Kao, Rowland R.; Biek, Roman; Menzies, Fraser; Trimble, Nigel; Harwood, Roland; Pepler, P. Theo; Oravcova, Katarina; Graham, Jordon; Skuce, Robin; du Plessis, Louis; Thompson, Suzan; Wright, Lorraine; Byrne, Andrew W.; Allen, AdrianBovine tuberculosis (bTB) is a costly, epidemiologically complex, multi-host, endemic disease. Lack of understanding of transmission dynamics may undermine eradication efforts. Pathogen whole-genome sequencing improves epidemiological inferences, providing a means to determine the relative importance of inter- and intra-species host transmission for disease persistence. We sequenced an exceptional data set of 619 Mycobacterium bovis isolates from badgers and cattle in a 100 km2 bTB 'hotspot' in Northern Ireland. Historical molecular subtyping data permitted the targeting of an endemic pathogen lineage, whose long-term persistence provided a unique opportunity to study disease transmission dynamics in unparalleled detail. Additionally, to assess whether badger population genetic structure was associated with the spatial distribution of pathogen genetic diversity, we microsatellite genotyped hair samples from 769 badgers trapped in this area. Birth death models and TransPhylo analyses indicated that cattle were likely driving the local epidemic, with transmission from cattle to badgers being more common than badger to cattle. Furthermore, the presence of significant badger population genetic structure in the landscape was not associated with the spatial distribution of M. bovis genetic diversity, suggesting that badger-to-badger transmission is not playing a major role in transmission dynamics. Our data were consistent with badgers playing a smaller role in transmission of M. bovis infection in this study site, compared to cattle. We hypothesize, however, that this minor role may still be important for persistence. Comparison to other areas suggests that M. bovis transmission dynamics are likely to be context dependent, with the role of wildlife being difficult to generalize.