Model of Selective and Non-Selective Management of Badgers (Meles meles) to Control Bovine Tuberculosis in Badgers and Cattle

Abstract

Bovine tuberculosis (bTB) causes substantial economic losses to cattle farmers and taxpayers in the British Isles. Disease management in cattle is complicated by the role of the European badger (Meles meles) as a host of the infection. Proactive, non-selective culling of badgers can reduce the incidence of disease in cattle but may also have negative effects in the area surrounding culls that have been associated with social perturbation of badger populations. The selective removal of infected badgers would, in principle, reduce the number culled, but the effects of selective culling on social perturbation and disease outcomes are unclear. We used an established model to simulate non-selective badger culling, non-selective badger vaccination and a selective trap and vaccinate or remove (TVR) approach to badger management in two distinct areas: South West England and Northern Ireland. TVR was simulated with and without social perturbation in effect. The lower badger density in Northern Ireland caused no qualitative change in the effect of management strategies on badgers, although the absolute number of infected badgers was lower in all cases. However, probably due to differing herd density in Northern Ireland, the simulated badger management strategies caused greater variation in subsequent cattle bTB incidence. Selective culling in the model reduced the number of badgers killed by about 83% but this only led to an overall benefit for cattle TB incidence if there was no social perturbation of badgers. We conclude that the likely benefit of selective culling will be dependent on the social responses of badgers to intervention but that other population factors including badger and cattle density had little effect on the relative benefits of selective culling compared to other methods, and that this may also be the case for disease management in other wild host populations.

Fig 1. The mean number of infected badgers per social group during the five years of control and five years afterwards inside the control area for simulations representing SW England.

Fig 2. The mean number of infected badgers per social group during the five years of control and five years afterwards within the entire simulation area for simulations representing SW England.

Fig 3. The mean number of infected badgers per social group during the five years of control and five years afterwards inside the control area for simulations representing Northern Ireland.

Fig 4. The mean number of infected badgers per social group during the five years of control and five years afterwards within the entire simulation area for simulations representing Northern Ireland.

Fig 5. The mean cattle herd breakdown (CHB) rate during the five years of control and five years afterwards inside the control area for simulations representing SW England.

Fig 6. The mean cattle herd breakdown (CHB) rate during the five years of control and five years afterwards within the entire simulation area for simulations representing SW England.

Fig 7. The mean cattle herd breakdown (CHB) rate during the five years of control and five years afterwards inside the control area for simulations representing Northern Ireland.

Fig 8. The mean cattle herd breakdown (CHB) rate during the five years of control and five years afterwards within the entire simulation area for simulations representing Northern Ireland.