Graduation Year

2024

Document Type

Thesis

Degree

M.S.

Degree Name

Master of Science (M.S.)

Degree Granting Department

Biology (Integrative Biology)

Major Professor

J. Sean Doody, Ph.D.

Committee Member

Andrew Kramer, Ph.D.

Committee Member

Mark Margres, Ph.D.

Keywords

conservation, disease, herpetology, mycosis, Squamata, urbanization

Abstract

Studying wildlife diseases is an important conservation measure, as many pathogens are a critical threat to biodiversity worldwide. Ophidiomycosis is an emerging infectious disease caused by the invasive fungal pathogen Ophidiomyces ophiodiicola that affects a wide variety of snake species, often causing mortality. There has been limited surveillance for ophidiomycosis in the southeastern United States’ (US) snake populations and research into the effects of anthropogenic disturbance on disease spread is also lacking. Thus, this project aimed to quantify the distribution and drivers (taxonomic, anthropogenic, and morphological) of ophidiomycosis in Florida, Louisiana, and Mississippi’s free ranging snakes as well as study the effects of urbanization on disease prevalence and severity using urban/non-urban paired systems. During 2022-2024, I sampled a total of 496 snakes across 42 species, detecting O. ophiodiicola in 22% of individuals. My research documents the first cases of ophidiomycosis for six snake species and provides the first record of the disease in Mississippi. We analyzed the effects of various factors on disease prevalence and severity across all of our samples using generalized linear mixed models, linear regression models, and Spearman rank correlation analyses. While urbanization showed a statistically significant but weak correlation with severity, it did not show a significant correlation with prevalence, though it approached significance; other factors such as subfamily and sex also influenced disease dynamics. Further filtered analysis of paired urban and non-urban sites revealed no significant difference in ophidiomycosis prevalence between these habitats. However, these paired sites revealed that O. ophiodiicola infection severity was significantly higher in urban environments than non-urban environments. These findings highlight the complex relationship between ophidiomycosis and urbanization, taxonomic classification, and other ecological factors. The potential of urban environments in exacerbating the condition of infected snakes without necessarily increasing infection rates underscores the importance of considering habitat quality in snake conservation efforts and disease management strategies. The present study provides crucial baseline data for future ophidiomycosis surveillance and emphasizes the need for long-term monitoring to better understand the disease's impact on snake populations in the southeastern US. Future research should focus on continued monitoring of under-sampled regions and snake species, laboratory studies on both the lethal and sublethal effects of ophidiomycosis, and molecular insights into the host-pathogen dynamics of this disease.

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