Uptake of buried baits by badgers: Implications for rabies control in Great Britain and the delivery of an oral TB vaccine

Abstract

The British Government's contingency plan for the control of wildlife rabies is based on oral vaccination around a focal outbreak, with the option of the targeted lethal control of foxes (Vulpes vulpes) and badgers (Meles meles) using buried poisoned bait. We investigated uptake by badgers of nonpoison meatbased baits buried along transects for 10 consecutive days in 1995. The original aim was to evaluate the likely effectiveness of this contingency option. However, the results are also pertinent to the development of an oral tuberculosis (TB) vaccine baiting strategy for badgers, for which research has primarily been carried out since this study was completed. Bait disappearance steadily increased over time, reaching an asymptote after 7 days. By incorporating iophenoxic acid biomarkers into baits, we showed that about 51% of subsequently captured badgers had consumed bait, the majority of which did so during the first 7 days. Bait uptake was significantly higher among adults. Rates of uptake by badgers of baits buried along transects could be increased by shortening the prebaiting period or extending the baiting period. However, considerably higher levels of uptake by adults and cubs are likely to be achieved by targeting bait deployment at badger setts, and this is now included in Britain's rabies contingency plan. Although meat-based baits cannot be used for TB control, the relevance of these results to the delivery of an oral TB vaccine bait to badgers is discussed. ß 2012 Crown copyright KEY WORDS badgers, bait uptake, biomarker, bovine tuberculosis, contingency plan, disease control, iophenoxic acid, Meles meles, rabies, vaccine bait.

Overview of Vaccination Trials for Control of Tuberculosis in Cattle, Wildlife and Humans

“…Oral baits would be the most convenient delivery system, and considerable progress has been made in this area with the encapsulation of BCG vaccine in a lipid matrix to reduce degradation of live BCG in the stomach and enhance shelf‐life of the vaccine in the field (Aldwell et al., ). Uptake of oral bait placebo vaccines has been shown to be high with 85–100% of wild possums accessing baits at bait densities of 40–80 sachets/ha (Cross et al., ) and uptake of buried baits in 51% of captured badgers after 7 days (Palphramand et al., ). Although oral bait delivery is a convenient system, it may be difficult to control the dose of vaccine consumed, number of animals vaccinated, age of vaccination, uptake by non‐target species and vaccine viability in the field.…”

The uptake of attractant and flavour enhanced baits by foxes (Vulpes vulpes) in rural England

“…However, improving bait uptake by foxes could also benefit other disease control scenarios, for example the distribution of anthelmintic baits for the control of Echinococcus multilocularis (Budgey, Learmount & Smith 2017), or indeed of improving bait uptake by other species; e.g. oral delivery of M. bovis vaccine in badgers (Palphramand et al 2012).…”