Wildlife risk mitigation protocols reduce risk species visits and pathogen marker detection in open-air farms

Outdoor farming systems may favor the dilution effect of biodiversity on pathogen exposure and contribute to biodiversity conservation through the preservation of valuable habitats. However, owing to the implicit closer interaction with wildlife, outdoor farms are also more at risk for disease maintenance at the wildlife-livestock interface. Disease control options in outdoor farming systems include the development and application of wildlife risk mitigation protocols (RMPs). However, while the nature of the proposed mitigation actions and the degree of farmer uptake have repeatedly been assessed, only limited information exists on their effectiveness. In this study, we revisited 14 farms of a pilot study to quantify the effect of applying RMPs on the detection rates of risk wildlife (assessed by means of camera traps [CTs]) and of selected pathogen markers (using sponges for environmental nucleic acid detection [ENAD]). The application of farm-specific RMPs resulted in a 30% reduction in farm visits by high-risk wildlife and an 18% reduction in the frequency of pathogen marker detection. High-risk species detection declined on 11 farms and increased on 3, all of them small ruminant farms. Regarding pathogen markers, we observed frequency reductions for four markers and increases for two markers. These changes were statistically significant for the Salmonella spp. marker invA. At the farm level, the reduction in the detection frequency of wild boar (Sus scrofa) correlated with the reduction in the detection frequency of the invA marker. These noninvasive methods may be relevant for assessing other interventions at the wildlife-livestock interface, regardless of the farmed species, farming system, and target pathogen.