Master of Science, The Ohio State University, 2024, Environment and Natural Resources

Sarcoptic mange, caused by the obligatory ectoparasite, Sarcoptes scabiei var canis, poses significant threats to wild canid populations, as it results in high levels of morbidity and mortality. Despite its impact, the disease dynamics and individual risk of infestation for coyotes (Canis latrans) in urban environments remain understudied. As human density within urban spaces continues to rise globally, understanding how disease dynamics within coyote populations is crucial for both wildlife conservation and public health. The Cook County Coyote Project, spanning from 2000 to 2023, has been examining sarcoptic mange infestations among radio-collared coyotes within the Chicago metropolitan area. In this study, we aim to (1) determine prevalence rates, identify causes of mortality, and elucidate general disease dynamics of sarcoptic mange and (2) identify specific covariates that influence an individual's likelihood of infestation within the Chicago coyote population. We found that sarcoptic mange prevalence was enzootic within our study site and was at a lower overall prevalence than studies conducted in rural areas. There was no significant increase in diagnoses between male and female coyotes; however, we were more likely to diagnosis coyotes with sarcoptic mange as adults than subadults or pups. 2% of the diagnosed coyotes fully recovered from gross lesions associated with sarcoptic mange. Coyotes that died from sarcoptic mange exposure were more common during the winter months. Individual likelihood of infestation was assessed using a generalized linear model using demographic and spatial covariates. Our best-fit model based on Akaike information criterion found that with a random effect for coyote ID, yearly home range composition and yearly age class were useful covariates in predicting individual risk of infestation; however, both fixed effects were non-significant. We hypothesize that sarcoptic mange infestations are rather influenced by inter-individua (open full item for complete abstract)

Committee: Stanley Gehrt (Advisor); Laura Pomeroy (Committee Chair); Risa Pesapane (Committee Chair) Subjects: Parasitology; Wildlife Conservation; Wildlife Management

Master of Science (MS), Bowling Green State University, 2022, Biological Sciences

Grand Lake St. Marys (GLSM) is a lake located in western Ohio, USA and is utilized for recreation, boating, fishing, and swimming. GLSM is a regionally important center for tourism and recreation bringing in nearly $150 million in annual revenue, but after three years of algal blooms and public health advisories, water-based recreation has reduced significantly in the region. Summer cyanobacterial blooms thrive due to both external and internal loading of phosphorus and are of great concern given that the city of Celina uses the lake as a water source for their community. Planktothrix agardhii, which dominates GLSM, can produce microcystin toxins that are known to be harmful to humans and animals. It is important that we understand the mechanisms driving and influencing these blooms. In this study, we examine Chytridiomycota (chytrids) and how these aquatic fungi can infect P. agardhii blooms. Rhizophydium sp. are known obligate parasites to Planktothrix, and these species have been found and isolated from the waters of Sandusky Bay (McKindles et al. 2021a). We investigated the spatial distribution of infections along with the effect that turbulence has on infectivity. Results of in-lake mesocosms, coupled with lab experiments, suggest that low levels of water turbulence can significantly reduce the infectivity of chytrids. Furthermore, infectivity is dependent on water temperature. Understanding different environmental conditions and the effect they have on infectivity provides valuable insights into controlling factors that may be limiting chytrid pathogenesis.

Committee: Christopher Ward Ph.D. (Committee Chair); R. Michael McKay Ph.D. (Committee Member); George Bullerjahn Ph.D. (Committee Member) Subjects: Aquatic Sciences; Freshwater Ecology; Limnology; Microbiology

Doctor of Philosophy, The Ohio State University, 1971, Graduate School

Committee: Not Provided (Other) Subjects: Biology

Doctor of Philosophy, The Ohio State University, 2016, Comparative and Veterinary Medicine

Surveillance for wildlife diseases is critical to our understanding of the emergence, transmission, persistence and control of infectious diseases at the interface of humans, domestic animals, and wildlife populations. Neospora caninum is a protozoan parasite capable of infecting a wide range of canid and ungulate species. The importance of the disease relates to economic losses, mainly derived from endemic or epidemic abortions in cattle. In the United States, coyotes and dogs are believed to be the main definitive hosts and white-tailed deer and cows are the main intermediate hosts. Our overall aim was to better understand the wildlife-livestock interface of N. caninum in natural settings. First, we estimated the true prevalence of N. caninum in three ruminant species by using Bayesian inference. We identified and discussed differences between apparent and true prevalence (TP). Differences in TP for some species suggest differences in the epidemiology of N. caninum for these co-located populations. Second, we evaluated the environmental phase of N. caninum shed in wild canid scats. Results suggested that the role of this environmental phase in the transmission to ruminants is likely minor. Finally, we evaluated the role of host species heterogeneity in the epidemiology of N. caninum circulating in a community. We identified differences in the patterns of immunity, age structure, and maternal and/or fetal antibody duration in three intermediate (ruminant) host species. Also, we estimated the species-specific contributions to the persistence of this pathogen in a community. This research was approached from the One Health perspective and provided a better understanding of N. caninum dynamics at the wildlife-livestock interface in an ecosystem.

Committee: Rebecca Garabed (Advisor); Mark Moritz (Committee Member); Barbara Wolfe (Committee Member); William Saville (Committee Member) Subjects: Animal Diseases; Applied Mathematics; Biology; Biostatistics; Computer Science; Conservation; Cultural Anthropology; Ecology; Environmental Health; Epidemiology; Geographic Information Science; Health Sciences; Livestock; Parasitology; Veterinary Services; Wildlife Conservation; Zoology

PhD, University of Cincinnati, 2015, Medicine: Toxicology (Environmental Health)

Cryptosporidiosis is an environmentally-associated human diarrheal disease caused by the etiological agent, Cryptosporidium. This parasitic pathogen is an intestinal protozoan that is abundant in the environment as highly resistant oocysts and can cause life-threatening consequences in immunosuppressed individuals. Of the various species found in the environment, one of the human-infective species is Cryptosporidium parvum. Parasite development and propagation occurs within a unique intracellular but extracytoplasmic parasitophorous vacuole at the apical surface of intestinal epithelial cells. Very little is known regarding the pathogenesis of C. parvum and what host factors are involved in infection. In order to assess differences in host susceptibilities, we compared several different host cell types using an in vitro model. Specifically, we introduced a new small intestinal epithelial cell type, FHs 74 Int, which supported better infection of C. parvum. Moreover, this cell type sustained the development and growth of the parasite over 48 hours. The molecular mechanisms of Cryptosporidium pathogenesis and the factors that cause variation in infection are poorly understood. Two different intestinal epithelial cells, HCT-8 and FHs 74 Int, had drastically different levels of infections, with the first supporting much less infection than the second. Using the FHs 74 Int model, we studied the expression patterns of several host factors before and after infection to C. parvum. One protein of interest was the tyrosine phosphatase Src homology-2 domain-containing phosphatase 2 (SHP-2). SHP-2, encoded by the human PTPN11 gene, is a ubiquitously expressed protein tyrosine phosphatase that acts on paxillin. In this study, we found that SHP-2 co-localizes at the apical end of the C. parvum infection site. Moreover, inhibition of SHP-2 abrogated complete infection and decreased phosphorylated levels of another protein-of-interest, paxillin. Paxillin is moderat (open full item for complete abstract)

Committee: Jagjit Yadav Ph.D. (Committee Chair); Susan Kasper Ph.D. (Committee Member); Susan Waltz Ph.D. (Committee Member); Ying Xia Ph.D. (Committee Member) Subjects: Environmental Health

Doctor of Philosophy, Miami University, 2015, Ecology, Evolution and Environmental Biology

The goals of this dissertation were to examine how patch and landscape level processes structure ant communities in agricultural landscapes and determine the relative roles of patch and host-level factors in determining ant-associated mite diversity and community composition. In Chapter 1, I examined ant richness, species frequencies, and community composition in 23 warm season constructed grasslands that varied in both patch and landscape level characteristics. Ant species richness was greater in older sites with sandier soils, while community composition was structured by soil texture, management, and urban land use. Frequency analyses for 14 ant species showed a wide range of responses to both patch and landscape components of the environment including age, management, soil texture, and surrounding land use. My findings support the use of ants as environmental indicators of disturbance in agricultural landscapes and show that diversity in constructed grasslands is structured by both patch and landscape level processes. In Chapter 2, I determined the relative importance of host and habitat for an ant-dependent commensalism (phoretic mites). I found that large, cosmopolitan, and abundant ant species support a greater proportion of the mite diversity. Additionally, I found that patch level characteristics, or environmental context (area, age, soil texture, and litter depth), of the host can alter the associated mite diversity. In Chapter 3, predictions of theory, herbivore resource hypotheses, and spatial parasitology were used to identify the extent of the ecological neighborhood for mites associated with ants. My results indicate that commensal mite communities are consistent with the Resource Size Hypothesis and are sensitive to ecological neighborhoods at multiple hierarchical levels including individual host ants, the host ant colony, surrounding nest community, and habitat type, but do not vary significantly among sites. In the final chapter, I examined the im (open full item for complete abstract)

Committee: Thomas Crist (Advisor); Hans Klompen (Committee Member); Melany Fisk (Committee Member); Ann Rypstra (Committee Member); John Maingi (Committee Member) Subjects: Biology; Ecology; Entomology

Doctor of Philosophy, The Ohio State University, 2012, Oral Biology

Leishmaniasis is a tropical disease caused by protozoan parasites. Leishmania donovani causes visceral disease with tropism for reticuloendothelial organs. Left untreated, L. donovani infections are fatal, often due to secondary bacterial infections and complications resulting from profound hepatosplenomegaly. Although Leishmania species are capable of parasitizing several different mammalian cell types, recent research has suggested that neutrophils may serve as early silent vectors for parasite entry into tissue macrophages, which are the definitive host cells and sites of parasite replication. Proper macrophage activation and parasite clearance is contingent upon hosts mounting type I CD4+ T cell (Th1) responses associated with the production of interleukin-12 and interferon-gamma (IFN-gamma). Signal transducer and activator of transcription 1 (STAT1) mediates the biological functions of IFN-gamma while STAT4 mediates the biological functions of IL-12. Interestingly, we found that while STAT1-deficient mice on a susceptible BALB/c background failed to mount protective Th1 responses, they were highly resistant to infection and developed little or no immunopathology compared with WT controls. We further found that STAT1 signaling in T cells was not involved in mediating immunopathology or susceptibility to L. donovani, suggesting that non-T cells recruited to the liver via STAT1-depdendent mechanisms may be involved in the pathogenesis of visceral leishmaniasis. We further found that phagocytes from STAT1-deficient mice had significant impairments in trafficking and parasite uptake compared with WT controls. These studies suggest that STAT1 signaling may mediate susceptibility by facilitating parasite uptake into host phagocytes. Similar to STAT1-deficient animals, STAT4-deficient mice were also unable to mount Th1 immune responses. However, STAT4 mice had significantly higher parasite burdens in their livers and spleens compared to WT animals. Additionally, STA (open full item for complete abstract)

Committee: Abhay Satoskar MD,PhD (Advisor); John Sheridan PhD (Committee Member); William Lafuse PhD (Committee Member); Michael Bailey PhD (Committee Member) Subjects: Immunology

Doctor of Philosophy, The Ohio State University, 2007, Pharmacy

Leishmaniasis is a parasite disease which currently afflicts 12 million people worldwide with two million new cases annually. Without treatment, visceral leishmaniasis is 100% fatal while other forms can be severely disfiguring and debilitating. Novel therapies are urgently needed; current treatments possess many negative attributes such as toxicity and loss of effectiveness due to resistance. Previous research demonstrated promising antileishmanial activity of several dinitroaniline sulfonamides. A QSAR evaluation of these compounds was performed using Catalyst software, generating a three-dimensional pharmacophore, and highlighting the specific functionalities of the compounds that confer antileishmanial activity. This pharmacophore was used to search the Maybridge database. Nineteen hits were tested for antileishmanial activity. Two compounds were highly active while another five compounds were moderately active (IC50 = 21-39 µM). The most potent compound, BTB06237 was also able to reduce parasite burdens in L. mexicana-infected J774 macrophages. TEM and fluorescence microscopy have shown that the single parasite mitochondrion becomes dilated and fragments into intensely staining, disjoined spheres following incubation with BTB06237. It appeared to cause mitochondrial membrane potential disruption, in parallel to that observed in parasites treated with the uncoupler FCCP. These data imply that BTB06237 disrupts mitochondrial structure and function. The presence of nitro groups on BTB06237 indicates that BTB06237 may increase the level of reactive oxygen species (ROS) in the parasites through redox cycling. Indeed, assays on treated parasites showed increased levels of ROS. Additionally, a structure-activity relationship study was performed by synthesizing and evaluating the antileishmanial activity of 16 total analogs. Regarding the phenylsulfanyl ring, antileishmanial potency was preserved regardless of the substituents, but loss of aromaticity lead to loss of a (open full item for complete abstract)

Committee: Karl Werbovetz (Advisor) Subjects:

Bachelor of Philosophy, Miami University, 2005, School Of Interdisciplinary Studies - Interdisciplinary Studies

Wildlife enclosures are argued by environmentalists and politicians alike as being beneficial entities for surrounding indigenous groups. These areas provide environmental, economic, educational, and cultural opportunities as well as promote eco-tourism and conservation values. However, negative consequences of these spaces must not be abandoned. While biodiversity positively affects the tourist sector, increasing biodiversity increases parasitic reservoirs and, thus, parasitic loads. Accordingly, health status and quality of life are in jeopardy for nearby populations. This thesis explores the methodology and importance of combining environmental and public health policy in the case of Leishmania in Kenya's game reserves.

Committee: Terry Perlin (Advisor) Subjects: Biology, Microbiology