Files
Abstract
Bats (Order Chiroptera) are a highly diverse and ecologically important group of mammals recognized for their unique biological traits and increasing relevance to infectious disease research. The Egyptian rousette bat (ERB; Rousettus aegyptiacus; common name Egyptian rousette) is the only confirmed natural reservoir host for orthomarburgviruses, Marburg virus and Ravn virus, and is a putative or confirmed reservoir for additional high-consequence zoonotic viruses. Despite its growing use in infectious disease modeling and immunologic research, fundamental gaps persist in our understanding of ERB biology, particularly regarding the species’ lymphoid system, background pathology in free-ranging populations, and host immune responses to diverse viral exposures. This dissertation addresses these gaps through a series of studies designed to 1) characterize the histologic architecture of the ERB lymphoid system, 2) characterize histology of free-ranging ERBs, and 3) evaluate viral shedding dynamics and long-term immunity in ERBs following inoculation with genetically diverse orthomarburgvirus isolates. These studies lay the immunologic and pathologic foundations of this reservoir species, providing a novel lymphoid tissue atlas and baseline health prolife for free-ranging ERBs. Experimental infection studies demonstrated that Ravn virus, despite its ~20% genetic divergence from Marburg virus, follows similar shedding kinetics and infection dynamics with increased rectal shedding. Furthermore, animals previously co-infected with diverse viruses mounted rapid, sterilizing immune responses upon homotypic and heterotypic inoculation, suggesting robust cross-protective immunity despite prior coinfection. Taken together, these findings expand our understanding of ERB reservoir competence and virus-host interactions, while establishing critical anatomical and immunological resources for future research. This work contributes to the broader fields of comparative pathology, viral ecology, and bat immunobiology, with direct implications for spillover risk assessment and the development of preclinical bat model systems for emerging zoonotic diseases.