Badger responses to small-scale culling may compromise targeted control of bovine tuberculosis

Bielby, Jon, Donnelly, Christl A., Pope, Lisa C., Burke, Terry and Woodroffe, Rosie (2014) Badger responses to small-scale culling may compromise targeted control of bovine tuberculosis. Proceedings of the National Academy of Sciences of the United States of America, 111 25: 9193-9198. doi:10.1073/pnas.1401503111


Author Bielby, Jon
Donnelly, Christl A.
Pope, Lisa C.
Burke, Terry
Woodroffe, Rosie
Title Badger responses to small-scale culling may compromise targeted control of bovine tuberculosis
Journal name Proceedings of the National Academy of Sciences of the United States of America   Check publisher's open access policy
ISSN 0027-8424
1091-6490
Publication date 2014-06-24
Sub-type Article (original research)
DOI 10.1073/pnas.1401503111
Open Access Status
Volume 111
Issue 25
Start page 9193
End page 9198
Total pages 6
Place of publication Washington, DC, United States
Publisher National Academy of Sciences
Collection year 2015
Language eng
Subject 1000 General
Formatted 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.

Significance
Bovine tuberculosis (TB) killed 1,500 people annually in 1930s Britain. TB control efforts still entail slaughtering many thousands of cattle annually, costing British farmers and taxpayers millions of dollars. Transmission from wild badgers impedes control of cattle TB, but nonselective badger culls confer limited benefits because culling changes badger behavior in ways that increase disease spread. A new plan to cull only test-positive badgers, and vaccinate test-negative badgers [termed test–vaccinate/remove (TVR)], is probably more publicly acceptable, and might be more effective if culling small numbers of badgers prompts no behavioral change. Unfortunately, this study shows that small-scale culling (such as TVR) changes badgers’ behavior in ways that risk increasing TB transmission among badgers and exacerbating cattle TB incidence rather than reducing it.
Keyword Bacillus Calmette-Guérin
Epidemiology
Wildlife management
Zoonotic disease
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Non HERDC
School of Biological Sciences Publications
 
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