Risk factors for bovine Tuberculosis at the national level in Great Britain
1 Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences University of Glasgow, 464 Bearsden Rd, Glasgow, G61 1QH, UK
2 Boyd Orr Centre for Ecology and Ecosystem health, College of Medical, Veterinary and Life Sciences University of Glasgow, 464 Bearsden Rd, Glasgow, G61 1QH, UK
3 The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
4 Environment Department, University of York, Heslington, York, YO10 5DD, UK
5 SAC, Roslin Institute Building, Easter Bush, Midlothian, EH25 9RG, UK
BMC Veterinary Research 2012, 8:51 doi:10.1186/1746-6148-8-51Published: 7 May 2012
The continuing expansion of high incidence areas of bovine Tuberculosis (bTB) in Great Britain (GB) raises a number of questions concerning the determinants of infection at the herd level that are driving spread of the disease. Here, we develop risk factor models to quantify the importance of herd sizes, cattle imports from Ireland, history of bTB, badgers and cattle restocking in determining bTB incidence. We compare the significance of these different risk factors in high and low incidence areas (as determined by parish testing intervals).
Large herds and fattening herds are more likely to breakdown in all areas. In areas with lower perceived risk (longer testing intervals), the risk of breaking down is largely determined by the number of animals that a herd buys in from high incidence areas. In contrast, in higher perceived risk areas (shorter testing intervals), the risk of breakdown is defined by the history of disease and the probability of badger occurrence. Despite differences in the management of bTB across different countries of GB (England, Wales and Scotland), we found no significant differences in bTB risk at the national level after these other factors had been taken into account.
This paper demonstrates that different types of farm are at risk of breakdown and that the most important risk factors vary according to bTB incidence in an area. The results suggest that significant gains in bTB control could be made by targeting herds in low incidence areas that import the greatest number of cattle from high incidence areas.