Evaluating Potential Deployment Strategies for Oral Delivery of Vaccines for Cervids

While vaccination is the most efficacious strategy for landscape-scale disease management, its success is predicated on overcoming concurrent hurdles in both laboratory-scale vaccine development and the logistical and behavioral complexities of field delivery to targeted wildlife populations, such as cervids. As laboratory effectiveness and successful field deployment of vaccines are interdependent, these efforts should be performed concurrently, with findings in one influencing progress in the other. A proactive approach for development of effective deployment strategies also minimizes any logistical bottlenecks that could occur following vaccine regulatory approval. This multiregional field study utilized a rotational crossover design across 19 sites in Alberta and Saskatchewan (May-August 2025) to quantify the behavioral efficacy of two candidate vaccine delivery matrices (thin film and liquid-filled packets [boba]) in combination with a variety of common cervid attractants. Remote camera monitoring was employed to assess target cervid (deer, elk, and moose) foraging preference, nontarget species uptake, and individual repeat visitation frequency. The thin-film matrix, presented within peas as food attractant, was found to be the optimal bait-delivery matrix maximizing target uptake. This analysis simultaneously quantified two critical operational hurdles (1) high nontarget consumption and (2) repeat consumption, or large-dose consumption, by individual cervids. These behavioral constraints invalidate a generic scatter-bait approach and underscore a challenge in delivery engineering. These findings provide the quantitative parameters required to support the development of a "smart" oral delivery system that incorporates remote species recognition and portion control to achieve cost-effective, single-dose delivery in wild populations.