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Badger culling to control TB in cattle has mixed effects

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Under embargo for

18.00 GMT/13.00 EST
Wednesday 14 December 2005

Widespread culling of badgers to control the incidence of bovine tuberculosis (TB) in cattle has simultaneously positive and negative effects, scientists report today.

According to a letter published in Nature, widespread culling of badgers caused a 19 per cent reduction in the incidence of cattle TB in the areas culled, but also led to a 29 per cent increase of TB in surrounding areas. The researchers suggest the increase is caused by the remaining badgers roaming more widely.

Badger culling can have mixed effects on controlling TB in cattle

The team had previously found that localised reactive culling increased TB incidence in cattle by 27 per cent. Ecological data suggests that increased badger movement caused both increases in TB incidence. Where badger population densities were reduced by culling, their usual territorial organisation broke down and the remaining badgers travelled longer distances potentially encountering more cattle.

Professor Christl Donnelly Opens in new window, from Imperial College London and first author, said: "The fact that widespread culling has both simultaneous negative and positive effects could have important implications for policies to control TB in cattle. Although we believe very large culling areas would act to reduce TB, it is not clear whether this would prove economically and environmentally sustainable."

Bovine tuberculosis can have serious consequences for cattle herds, and if found to be infected, cattle are compulsorily slaughtered. Although the infection can be spread from cattle to humans, the risk is extremely low due to routine testing of cattle for infection and pasteurisation of milk and milk products.

The study was funded by the Department of Environment, Food and Rural Affairs (DEFRA).

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Notes to editors:

1. Positive and negative effects of widespread badger culling on tuberculosis in cattle, Nature.

2. The Nature paper is being published in tandem with a complementary paper in the Journal of Applied Ecology. The embargo for this paper will be lifting the same time as the Nature paper. For more info please contact: Becky Allen, Press Officer (British Ecological Society, London, UK) Tel: +44 (0)1223 570 016 Email:

3. The earlier paper on the impact of localised reactive culling was published in Nature in 2003.

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