Test and vaccinate or remove: Methodology and preliminary results from a badger intervention research project

Abstract

Background: In the British Isles, it is generally accepted that the Eurasian badger (Meles meles) plays a role in the maintenance of bovine tuberculosis (bTB) in cattle. Non‐selective culling is the main intervention method deployed in controlling bTB in badgers along with smaller scale Bacillus Calmette–Guérin (BCG) vaccination areas. This paper describes the use of selective badger culling combined with vaccination in a research intervention trial. Methods: In Northern Ireland, a 100 km2 area was subjected to a test and vaccinate or remove (TVR) badger intervention over a 5‐year period. Badgers were individually identified and tested on an annual basis. Physical characteristics and clinical samples were obtained from each unique badger capture event. Results: A total of 824 badgers were trapped with 1520 capture/sampling events. There were no cage‐related injuries to the majority of badgers (97%). A low level of badger removal was required (4.1%–16.4% annually), while 1412 BCG vaccinations were administered. A statistically significant downward trend in the proportion of test positive badgers was observed. Conclusion: This is the first project to clearly demonstrate the feasibility of cage side testing of badgers. The results provide valuable data on the logistics and resources required to undertake a TVR approach to control Mycobacterium bovis in badgers.

Effect of selective removal of badgers (Meles meles) on ranging behaviour during a ‘Test and Vaccinate or Remove’ intervention in Northern Ireland

“…The mean distance between adjacent active main setts was calculated to be 820 m and followed a dispersed (nonclustered) pattern (z-score = 5.042; P value < 0.001). The vast majority (89%) of GPS collars were recovered/accounted for after they stopped transmitting (117 (75%) were recovered at a Based on an estimated population of 560 badgers [20].…”

“…The DPP VetTB test is a single use, point of care, immune-chromatographic (lateral-flow) rapid test for the detection of antibodies to Mycobacterium tuberculosis and M. bovis in cervid serum. Whole blood was used to determine the badger's bTB status in the field [20, 24].…”

“…A badger population estimate within the study area was obtained based on results from previous research [20, 26] and the Lincoln-Peterson Method using trapping data [27]. Distances between active main setts were calculated using the ‘Nearest Neighbour Tool’ in ArcGIS 10.3.1 (ESRI systems, USA) in order to provide background information into the badger density in the area.…”

“…In years 2-4, DPP test negative badgers were vaccinated and released while DDP test positive badgers were euthanised using pentobarbitone (140 mg/kg by intravenous injection). The vaccine used was Badger BCG (BCG Danish strain with 2-8 × 10 6 colony forming units per dose; intramuscular administration) during years 1-3 and BCG Sofia (Intervax Ltd, Canada; BCG Sofia strain with 1.5-6.0 × 10 6 colony forming units per dose; intramuscular administration) during the years thereafter [20].…”

“…The intervention involved selective removal of bTB test positive badgers and vaccination and release of bTB test negative badgers. This so called 'Test and Vaccinate or Remove' (TVR) approach involved a lower level of badger removal than non-selective culling and it was therefore considered more publicly acceptable [20]. Furthermore, a combination of selective removal of bTB infected badgers (rather than all captured badgers in non-selective culling interventions) in parallel with BCG vaccination to boost the immunity level of the remaining badger population should provide a synergy enabling accelerated control of bTB infection within the badger population [20].…”