Degree

Doctor of Philosophy (PhD)

Department

Pathobiological Sciences

Document Type

Dissertation

Abstract

Arthropod-borne viruses (arboviruses) continue to emerge and expand into new geographic regions, driven by factors such as climate change and increased globalization. The genus Orthobunyavirus represents one of the most diverse and globally distributed viral groups yet remains comparatively understudied. While several members have been associated with significant disease, most lack basic experimental characterization. This gap means foundational experimental systems must be established de novo for each virus due to the absence of prior characterization and ultimately delays and/or limits our ability to interpret surveillance data, assess transmission risk, and respond effectively to potential emergence events. Characterization of arboviruses falls on a continuum from basic laboratory phenotyping to more complex virus-vector-vertebrate-environment interactions. Intrinsic viral properties, including replication kinetics, cytopathic effects, and vector competence can offer insights into viral fitness and provide a foundation for downstream experimental and comparative analyses. Additional factors, such as environmental conditions or host-virus interactions, can further modulate these dynamics in ways that are not well understood for many Orthobunyaviruses.

In this work, where no data existed previously, there is now lab-based phenotypic characterization of seven Orthobunyaviruses: Capim, Guama, Guaroa, Trubanaman, Tete, Caraparu, and Wyeomyia. These viruses differed in their phenotypic characteristics, providing the basis for future hypotheses to further investigate the biology of these neglected arboviruses. Diagnostics are also sparse for this group, and so singleplex and multiplex assays were designed to facilitate surveillance and diagnostics, with mixed results. In addition, this work provides the first evidence that Louisiana is at risk for the emergence of Batai, an Orthobunyavirus that affects ruminants and birds and has the potential to cause economic losses across agricultural and game sectors. Finally, this work demonstrates that while reassortment is not temperature dependent, the precursor process of coinfection is. Further, it is the first to demonstrate that Bunyamwera and Batai coinfect and produce reassortants in C6/36 insect cells. Taken together, this work characterized several Orthobunyaviruses to fill gaps along the characterization pipeline and better position the Orthobunyavirus research community to continue scientific investigations and ultimately be prepared for arboviral emergence.

Date

5-22-2026

Committee Chair

Rebecca Christofferson

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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