The effects of annual widespread badger culls on cattle tuberculosis following the cessation of culling.
BACKGROUND
The effective control of human and livestock diseases is challenging where infection persists in wildlife populations. The Randomised Badger Culling Trial (RBCT) demonstrated that, while it was underway, proactive badger (Meles meles) culling reduced bovine tuberculosis (TB) incidence inside culled areas but increased incidence in neighboring areas, suggesting that the costs of such culling might outweigh the benefits.


OBJECTIVE
The objective of this study was to investigate whether culling impacts persisted more than one year following the cessation of culling (the 'post-trial' period). We compared TB incidence in and around RBCT proactive culling areas with that in and around matched unculled areas.


RESULTS
During the post-trial period, cattle TB incidence inside culled areas was reduced, to an extent significantly greater (p=0.002) than during culling. In neighboring areas, elevated risks observed during culling were not observed post-trial (p=0.038). However, the post-trial effects were comparable to those observed towards the end of the trial (inside RBCT areas: p=0.18 and neighboring areas: p=0.14).


CONCLUSIONS
Although to-date the overall benefits of culling remain modest, they were greater than was apparent during the culling period alone. Continued monitoring will demonstrate how long beneficial effects last, indicating the overall capacity of such culling to reduce cattle TB incidence.
Jenkins
Helen E
HE
MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, Norfolk Place, London W2 1PG, UK.
Woodroffe
Rosie
R
Donnelly
Christl A
CA
D000818:Animals; D002417:Cattle; D004197:Disease Reservoirs / Q000382:microbiology / Q000662:veterinary*; D005500:Follow-Up Studies; D006702:Homing Behavior; D045969:Mustelidae / Q000382:microbiology*; D009163:Mycobacterium bovis; D010571:Pest Control / Q000379:methods*; D014380:Tuberculosis, Bovine / Q000517:prevention & control* / Q000635:transmission; D006113:United Kingdom