Doctoral Dissertations

Date of Award

12-2020

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Comparative and Experimental Medicine

Major Professor

Marcy J. Souza

Committee Members

Richard W. Gerhold, Adam S. Willcox, Charles Masembe, Chika Okafor

Abstract

The emergence of zoonotic pathogens through contact with animal reservoirs is a well-documented phenomenon and growing concern for public health. Particularly in light of the ongoing Ebola epidemic in the Democratic Republic of the Congo and the coronavirus pandemic, the need to understand mechanisms of contact and disease transmission at the human-wildlife interface and to understand which infectious agents may reside within wildlife reservoirs crucial. In this project, we investigated the potential introduction of zoonotic cestode Echinococcus canadensis to public lands in Tennessee subsequent to elk translocation effort and aimed to identify whether a transmission cycle was established in this area. We further aimed to elucidate drivers of zoonotic infections in the bushmeat trade in northern Uganda by assessing the phenomenon of ‘species deception’, evaluate social factors influencing participation in the bushmeat trade and risk for zoonosis exposure, and describe bacterial microbial diversity in market bushmeat in the area. We confirmed the presence of E. canadensis, with histological confirmation in 75% of elk included in our study and PCR confirmation in 50% of elk. Our findings in bushmeat in northern Uganda demonstrate nearly 30% mismatch between what bushmeat species are sold as in market and the true identity of these species based on PCR and Sanger sequencing. Surveys of hunters and cooks in communities adjacent to Murchison Falls National Park revealed that both hunters and cooks have the highest awareness of monkeypox and gastrointestinal illness as diseases that wildlife can carry. Self-reported injuries while cooking or butchering bushmeat were reported to be infrequent among both hunters and cooks. While cooks believed that hunters and dealers never described primate meat as another kind of animal, hunters reported usually doing this. Microbial diversity among wildlife samples was found to be high, regardless of tissue condition or wildlife species. Furthermore, 16s rRNA signatures of numerous Select Agent bacterial genera associated with significant human illness were detected in these samples. Microbial composition suggests that bushmeat microbiota is comprised of a combination of endogenous infections, environmental contamination, and spoilage associated bacteria. Regardless, the potential health consequences of unmitigated exposure to these microbes presents a clear risk to individual and global health. The findings of this project underscore the need for practical and culturally appropriate educational strategies to help hunters both in the United States and Uganda enact proper handling and butchering techniques to minimize contact with bodily tissues of wild animals.

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