Predicting prolonged bovine tuberculosis breakdowns in Great Britain as an aid to control

K Karolemeas, T J McKinley, R S Clifton-Hadley, A V Goodchild, A Mitchell, W T Johnston, A J K Conlan, C A Donnelly, J L N Wood

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Bovine tuberculosis (bTB) is an important notifiable disease in cattle in Great Britain (GB), and is subject to statutory control measures. Despite this, disease incidence has increased since the mid-1980s, and around 30% of herd breakdowns continue for more than 240 days. This is twice the shortest possible time for confirmed breakdowns to test clear from infection (≈120 days), and four times the shortest possible time for unconfirmed breakdowns (≈60 days). These "prolonged" breakdowns consume substantial resources and may act as an ongoing source of infection. It is not clear why some breakdowns become prolonged. Existing detailed case-control data have been re-analysed to determine risk factors for breakdowns lasting longer than 240 days, the strongest of which was the confirmation status of the breakdown: OR 12.6 (95%CI: 6.7-25.4). A further model restricted to data available early on in a breakdown for all breakdowns nationally, can predict 82-84% of prolonged breakdowns with a positive predictive value of 44-49% when validated using existing national datasets over a 4-year period. Identification of prolonged breakdowns at an earlier stage could help to target bTB controls in GB.
Original languageEnglish
Pages (from-to)183-90
Number of pages8
JournalPreventive veterinary medicine
Issue number3-4
Publication statusPublished - 1 Dec 2010

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