Validating Wing Biopsies for Blood-Borne Pathogen Characterization in Bats

Wildlife surveillance is critical for tracking disease emergence, characterizing pathogen diversity, and assessing spillover risks. Blood-borne pathogens are of particular interest for such efforts due to their global distribution, broad host taxa, and zoonotic potential. Despite the need to monitor blood-borne pathogens, blood collection is costly for biologists and sampled wildlife (i.e., time-consuming and stressful), hindering our ability to expand surveillance efforts. Using vascular tissues to detect infections can minimize sampling effort and stress on wildlife, but it is unclear how pathogen detection and characterization from these tissues compared to blood. To evaluate the reliability of using vascular tissues for detecting blood-borne pathogens in wildlife, we collected paired samples of blood and wing biopsies from common vampire bats (Desmodus rotundus) and molecularly screened for bartonellae, hemotropic mycoplasmas (hemoplasmas), and trypanosomes. Probabilities of detection were lower in wing tissues than in blood for all pathogens, possibly due to blood vessel avoidance when collecting the former. However, we detected infection in wing tissues of at least two individual bats for each pathogen. Paired-positive individuals mostly showed high sequence concordance between tissues, and sample sizes needed to detect a single infection and observed prevalences were similar (i.e., n = 10-39). Due to lower probabilities of infection in wing tissues compared to blood, we suggest that using these samples to estimate infection prevalence of blood-borne pathogens is not ideal. However, our results demonstrate that vascular tissues can be used for initial pathogen assessment and discovery to help target surveillance efforts in the future.