Vaccination of badgers and the control of TB

Abstract

Wildlife diseases can threaten biodiversity, infect humans and domestic animals, and cause significant economic losses. In the UK, bovine tuberculosis persistently affects cattle; some disease control methods target the European badger which acts as a reservoir for the disease. Administering Bacillus Calmette-Guérin vaccine to badgers is a potential approach to reducing the prevalence of the disease across species. The aim of my studies is to establish whether vaccination, and the potential reduction in disease load, is associated with changes to badger life-history and behaviour. Further investigation is directed at understanding observed variation in bait uptake and badger behaviour towards deployed baits. Analysis investigates whether behaviour or uptake are associated with land-type classes within territories. The findings I present reveal no significant associations between vaccination and the life-history traits investigated. Both bait uptake rate and behaviour towards bait are shown to have significant associations with the proximity and area of broadleaf woodland/pasture or arable land in the territory. An interesting association showed decreased neophobic behaviour at setts in closer proximity to human habitation. Vaccinated individuals were found to produce significantly lower quantities of gamma-interferon after infection. These additional findings and their relevance to wildlife disease management are discussed. The results presented give reassuring evidence that vaccination is unlikely to give undesirable side effects; whilst improving understanding of the factors that may affect oral bait vaccination campaigns. Further studies are vital to establish whether vaccination campaigns will reduce the negative impact of bovine tuberculosis in terms of economic impact or health impacts on humans and cattle.