Advancing disease surveillance and biosecurity in North American bison (Bison bison): multidisciplinary approaches to bison health monitoring

Abstract

North American bison (Bison bison) play a critical ecological, cultural, and economic role, yet their long-term conservation and management face challenges from disease threats, anthropologic changes, and translocation-associated risks. This dissertation integrates a One Health approach to assess key aspects of bison health, disease surveillance, and biosecurity policy through a multidisciplinary framework. Specifically, this research (1) establishes a stakeholder-driven definition of bison health, (2) evaluates the epidemiology of Bluetongue Virus (BTV) and Epizootic Hemorrhagic Disease Virus (EHDV) in bison, and (3) assesses the diagnostic performance of serological assays for Mycoplasma bovis, a pathogen of increasing concern. To define bison health from a multisectoral perspective, a two-round Delphi survey was conducted with experts from public, tribal, nonprofit, and private sectors. Experts defined bison health as the ability of populations to express natural behaviors, demonstrate resilience to external stressors, and sustain high reproductive output with minimal intervention. Mycoplasma bovis was identified as a high-priority pathogen, with participants highlighting the urgent need for improved diagnostics, biosecurity measures, and cross-sectoral disease management strategies. In response to the research and biosecurity gaps in bison health identified in the Delphi manuscript, as well as the expanding geographical range of Orbiviruses in the United States, we conducted the first cross-sectional serosurvey of BTV and EHDV in North American bison. This study analyzed samples from 287 animals across nine herds in seven U.S. states. Competitive ELISA assays revealed a seroprevalence of 56.5% for BTV and 57.5% for EHDV, with logistic regression identifying age as a significant predictor of seropositivity (p < 0.01). PCR-based detection of circulating BTV serotypes (6, 11, 13, 17) was noted, indicating exposure to endemic serotypes. Additionally, a significant decline in viremia with increasing age suggesting age-related immune dynamics. These findings provide foundational data for incorporating bison into vector-borne disease surveillance and highlight the need for further investigation into their role as incidental hosts. Given the increasing impact of M. bovis on bison health along with the economic impacts highlighted in the Delphi manuscript, this dissertation also evaluates the diagnostic performance of a newly designed P48 ELISA compared to a commercially available ELISA for M. bovis detection in bison. This chapter assesses sensitivity, specificity, and cross-reactivity, identifying key limitations of current assays and providing recommendations for improving serological surveillance in bison populations. Findings from this study emphasize the need for species-specific diagnostic validation to enhance disease monitoring and outbreak prevention. By integrating Delphi consensus-building, epidemiological surveillance, and diagnostic evaluation, this dissertation provides critical insights into bison disease ecology, biosecurity needs, and translocation risks. The findings support evidence-based policies for disease mitigation and contribute to the sustainable management of bison populations under a One Health framework.