Environmental risk factors associated with bovine tuberculosis among cattle in high-risk areas.

Our research shows that environmental features are important predictors of bovine tuberculosis (bTB) in British cattle herds in high-prevalence regions. Data from 503 case and 808 control farms included in the randomized badger culling trial (RBCT) were analysed. bTB risk increased in larger herds and on farms with greater areas of maize, deciduous woodland and marsh, whereas a higher percentage of boundaries composed of hedgerows decreased the risk. The model was tested on another case-control study outside RBCT areas, and here it had a much smaller predictive power. This suggests that different infection dynamics operate outside high-risk areas, although it is possible that unknown confounding factors may also have played a role.