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Evaluation of a bait-marking system for badgers using SDM and RB as biomarkers
Journal University College Dublin - Faculty of Veterinary Medicine Abstract The use of biomarkers play an important role in the evaluation of bait uptake in field studies assessing oral vaccine strategies. The technique relies on using non-toxic biomarker substances incorporated into baits to 'mark' the animals that consume the baits. In a previous study (Southey and others 2000), we showed that iophenoxic acid and tetracycline were effective biomarkers for determining the bait contact status of individual badgers. However, analysis of the data obtained suggested that they are unsuitable for large-scale use in vaccine delivery programmes; iophenoxic acid is expensive and blood samples must be irradiated prior to analysis. In addition, measurement of uptake of tetracycline only provides a retrospective record of bait uptake as it is based on post-mortem examination of sectioned teeth samples. In the present study we evaluated a bait-marking system for badgers consisting of sulfadimethoxine (SDM) and rhodamine b (RB) as biomarkers. Biomarked baits were distributed for three consecutive days in five test territories. A separate control territory was fed with nonbiomarked baits. The study was carried out to assess, (1) The effect of SDM and RB on bait acceptance, (2) The marking capacity of SDM and RB in serum and hair samples taken from badgers captured after bait distribution. Of the badgers (n=26) trapped in the test territories, 18 (69%) gave positive results when tested for both biomarkers. Conversely, none of the badgers (n=6) trapped in the control territory were biomarker positive. Analysis of blood serum and hair samples indicated that SDM and RB persisted for up to or at least 8 days after bait ingestion. These results indicate that the biomarkers SDM and RB act as reliable systemic markers and have potential application in field trials to monitor oral vaccine uptake by badgers. Keywords Bait-Marking System for Badgers Web site University College
Dublin - Faculty of Veterinary Medicine |
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