Fully understanding anuran disease requires consideration of the entire pathogen landscape, which is often comprised of numerous pathogenic organisms. In natural populations, pathogens interact within hosts either directly, in competition for host resources, or indirectly, by influencing host immunity. Multiple concurrent infections, or co-infections, can have diverse and major ramifications for both host and pathogen depending on the combination of infecting organisms. Likewise, the order of pathogen exposure, known as priority effects, plays a significant role in shaping disease dynamics. In my dissertation I will utilize natural populations and experimental cohorts of ranid hosts to investigate Ranavirus-Perkinsea co-infection consequences under an integrative framework of immunogenetics, ecology and evolution. In chapter one I will test the effects of Rv-Pr co-infection on host fitness through metrics of mortality, behavior and body condition, while also establishing Pr as a causative disease agent. Chapter two will examine how the order of pathogen exposure influences the pathogen load and virulence of co-infecting pathogens. Lastly, in Chapter 3 I will explore how genetic variation predicts single and co- and tri- infections between Rv, Pr and Bd leveraging an existing dataset of American bullfrogs (Rana catesbeiana) sampled across their natural and introduced range.
Erin Brosnan
Advisor: Dr. Ana Savage
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