Matthew Ingle


Baylisascaris procyonis is a nematode parasite that infects the small intestines of raccoons (Procyon lotor). Raccoons are the definitive host for this parasite, which can have both an indirect and direct life cycle. In intermediate hosts, the parasite causes serious pathology resulting from larvae migrating through host tissue to the brain. Infection via exposure to B. procyonis eggs is fatal in over 90 vertebrate species that serve as intermediate hosts, including humans. The zoonotic potential of B. procyonis makes understanding factors that impact prevalence and pathology in raccoons important for management strategies. Alimentary canals from 226 raccoons trapped in nine townships of southwestern Ohio were collected and necropsied along the full length of the intestines. All B. procyonis individuals found were collected, noting the presence and abundance in each raccoon necropsied. Using these data, we compared the nine townships, and noted that Beavercreek Township had significantly lower B. procyonis prevalence than any other township. To determine how landscape features impact B. procyonis prevalence, the proportion of urban versus agricultural land use and mean patch size were calculated for each township. We found that the total proportion of landscape modified by agriculture was the best predictor of B. procyonis prevalence. We also isolated DNA from tissue of the greater omentum from the raccoons, and amplified four loci. We used the sequences from NADH5 to build phylogenetic trees for the nine townships, and used the other three loci to demonstrate evidence of genetic structuring and determine the impact of B. procyonis on raccoon population genetics. There is evidence of genetic structuring, and raccoons from areas with lower (< 60%) B. procyonis prevalence had more genetic variability than other raccoon populations. Finally, we removed the stomach contents from each raccoon, noting the type of tissue found and calculating the proportion of the total mass made up of plant tissue. Raccoons from areas with lower B. procyonis prevalence had significantly less plant material in the stomachs at necropsy than other raccoons. These data demonstrate that we can predict B. procyonis prevalence from landscape features, and that B. procyonis impacts raccoon genetics and behavior.

LLU Discipline



Earth and Biological Sciences


School of Medicine

First Advisor

Dunbar, Stephen G.

Second Advisor

Brand, Leonard R.

Third Advisor

Gibson, James

Fourth Advisor

Hayes, William K.

Fifth Advisor

Standish, Timothy

Degree Name

Doctor of Philosophy (PhD)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Baylisascaris procyonis; Raccoon -- Parasites; Raccoons as carriers of disease; Veterinary parasitology; Host-parasite relationships

Subject - Local

Ascaridida Infections -- transmission; Parasitic Diseases; Animal; Baylisascaris procyonis - Distribution



Page Count


Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website


Loma Linda University. Del E. Webb Memorial Library. University Archives