Biomarkers of pathogen exposure in wild boar for integrated wildlife monitoring

Wildlife health surveillance is relevant for the control of shared infections at the wildlife-domestic animal-human interface. The Eurasian wild boar (Sus scrofa) has been identified as a reliable sentinel species for a wide variety of pathogens. In addition to pathogen-specific antibody detection, indirect biomarkers have been proposed as an additional tool for health assessment. This study aims to identify serum biomarkers with good predictive capacity for individual pathogen exposure richness, i.e., the number of pathogens against which antibodies are detected in a single host. We assessed the presence of antibodies against 14 pathogens in 225 wild boar from the Iberian Peninsula, as well as the serum levels of two acute phase proteins (APPs; haptoglobin and C-reactive protein), a redox balance marker (CUPRAC), and an immune response indicator (ADA). We also assessed the antibody production against the glycan galactose-α-1,3-galactose (alpha-gal; α-GAL). Our results demonstrated that α-GAL is a valuable biomarker of pathogen exposure since it was the only one consistently correlated with individual pathogen exposure richness, as well as the one with the highest discriminatory power. Overall, this research supports that screening of wild boar sera for anti-α-GAL antibodies could serve as a broad-spectrum indicator for pathogen exposure, supporting its potential inclusion in integrated monitoring schemes, complementing traditional pathogen screening approaches.