Abstract
Regionalization, the use of stricter disease and wildlife management controls in certain areas, has been proposed as a method to bring about the eradication of Bovine Tuberculosis (bTB) in Ireland. We used spatial Information to compute metrics for the selection of counties within Ireland where such stricter controls could be applied. Counties were ranked based on cattle demographics, bTB prevalence, farm fragmentation, movement network measures, information on badger abundance and control, and the predicted impact of risk based trading on cattle sales.
Herd fragmentation was measured as the percentage of herds with land outside of the county and also the percentage of land fragments whose home farm was in another county. These two metrics closely matched each other for a given county, but they varied considerably between counties, from 1% to 24%. Movement network information was combined with a herd risk model based on network metrics, badger abundance and herd and environmental characteristics to evaluate the proportion of moves which would be deemed high-risk under a risk-based trading regime. This would result in up to 53% of a county’s cattle sales and 42% of its herds being affected. This was compared to a more conservative approach which may be more practical to implement, which was based purely on the test history of each herd. This second approach resulted in a much smaller number of trades being potentially restricted. Wildlife metrics related to badger control and vaccination also varied considerably between counties. We also used information on cattle market sales to calculate cattle market catchment areas, as an alternative to counties a candidates for regionalized control.
These results will be used by the Irish government to select candidate areas for stricter bTB control measures.