title: Badger responses to small-scale culling may compromise targeted control of bovine tuberculosis.
abstract: Where wildlife disease requires management, culling is frequently considered but not always effective. In the British Isles, control of cattle tuberculosis (TB) is hindered by infection in wild badger (Meles meles) populations. Large-scale badger culling can reduce the incidence of confirmed cattle TB, but these benefits are undermined by culling-induced changes in badger behavior (termed perturbation), which can increase transmission among badgers and from badgers to cattle. Test-vaccinate/remove (TVR) is a novel approach that entails testing individual badgers for infection, vaccinating test-negative animals, and killing test-positive animals. Imperfect capture success, diagnostic sensitivity, and vaccine effectiveness mean that TVR would be expected to leave some infected and some susceptible badgers in the population. Existing simulation models predict that TVR could reduce cattle TB if such small-scale culling causes no perturbation, but could increase cattle TB if considerable perturbation occurs. Using data from a long-term study, we show that past small-scale culling was significantly associated with four metrics of perturbation in badgers: expanded ranging, more frequent immigration, lower genetic relatedness, and elevated prevalence of Mycobacterium bovis, the causative agent of TB. Though we could not reject the hypothesis that culling up to three badgers per social group might avoid perturbation, we also could not reject the hypothesis that killing a single badger prompted detectable perturbation. When considered alongside existing model predictions, our findings suggest that implementation of TVR, scheduled for 2014, risks exacerbating the TB problem rather than controlling it. Ongoing illegal badger culling is likewise expected to increase cattle TB risks.
authors.affiliation: Institute of Zoology, Regent's Park, London NW1 4RY, United Kingdom;
authors.forename: Jon
authors.initials: J
authors.lastname: Bielby
authors.affiliation: Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, United Kingdom; and.
authors.forename: Christl A
authors.initials: CA
authors.lastname: Donnelly
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom.
authors.forename: Lisa C
authors.initials: LC
authors.lastname: Pope
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom.
authors.forename: Terry
authors.initials: T
authors.lastname: Burke
authors.affiliation: Institute of Zoology, Regent's Park, London NW1 4RY, United Kingdom; rosie.woodroffe@ioz.ac.uk.
authors.forename: Rosie
authors.initials: R
authors.lastname: Woodroffe
mesh_terms: D000818:Animals; D002417:Cattle; D005260:Female; D008297:Male; D008954:Models, Biological; D045969:Mustelidae / Q000276:immunology / Q000382:microbiology; D009163:Mycobacterium bovis / Q000276:immunology*; D032581:Tuberculosis Vaccines / Q000276:immunology / Q000494:pharmacology; D014380:Tuberculosis, Bovine / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control / Q000635:transmission; D006113:United Kingdom
chemical_list: D032581:Tuberculosis Vaccines
keywords: Bacillus Calmette-Guérin; epidemiology; wildlife management; zoonotic disease