Specificity and success of oral-bait delivery to Eurasian wild boar in Mediterranean woodland habitats

Eurasian wild boar (Sus scrofa) is an important reservoir host for pathogens affecting humans and domestic animals. The eradication of these diseases may require the development of control strategies that reduce pathogen transmission between wildlife and domestic animals. Baiting for oral vaccine delivery is often considered for wildlife disease control. The effective and efficient field vaccination of wildlife requires species-specific baits as delivery vehicles for oral vaccines and designing appropriate baiting strategies. The objective of this study was to determine the proportion of young and adult wild boar and non-target animals that consumed baits containing a chemical marker, iophenoxic acid (IPA), in delivery trials conducted in summer in four different sites in the Mediterranean region of Spain where wild boar are abundant. The proportion of wild boar showing IPA markers in serum in autumn ranged from 11.5% to 56.4%. When attending to age classes, 12.6% to 72.7% of young individuals presented IPA. The results evidenced that the percent of wild boar that ingested the baits varied among study sites and age classes. Placing baits inside selective cages (for juveniles) and under heavy pavel stones (for adults) contributed to improve age specificity in bait consumption. We suggest ways for improving the age specificity of bait delivery systems used for young and adult wild boar.