Animal Diseases Commons^™

An Overview Of Tsetse Fly Repellents: Identification And Applications, Olabimpe Y. Orubuloye, Njelembo J. Mbewe, David P. Tchouassi, Abdullahi A. Yusuf, Christian W.W. Pirk, Baldwyn Torto

All Peer-Reviewed Publications

Tsetse flies are vectors of the parasite trypanosoma that cause the neglected tropical diseases human and animal African trypanosomosis. Semiochemicals play important roles in the biology and ecology of tsetse flies. Previous reviews have focused on olfactory-based attractants of tsetse flies. Here, we present an overview of the identification of repellents and their development into control tools for tsetse flies. Both natural and synthetic repellents have been successfully tested in laboratory and field assays against specific tsetse fly species. Thus, these repellents presented as innovative mobile tools offer opportunities for their use in integrated disease management strategies.

Exploring The Dynamic Adult Hard Ticks-Camel-Pathogens Interaction, John Mark O. Makwatta, Paul N. Ndegwa, Florence A. Oyieke, Peter Ahuya, Daniel K. Masiga, Merid N. Getahun

All Peer-Reviewed Publications

The ability of ticks to interact and adapt to differentecologies and hosts determines their vectorial competence for various pathogens; however, ticks-livestock-pathogens interaction studies are limited. With our ticks-hosts-pathogens interface studies, we found 14 species of hard ticks feeding on various livestock. Ticks showed a strong preference for one-humped camels (Camelus dromedarius). The camel nostril was the most preferred predilection site. The most prevalent tick species on camels was Hyalomma rufipes. We found two novel Amblyomma gemma variants which are distinct both morphologically and genetically from previously described Amblyomma gemma. The signature odors from camel breath and body were attractive to …

Ophidiomyces Ophidiicola And Texas Snakes: A Field To Bench Study Of Ophidiomycosis, Kenlynn L. Volz

Biology Theses

Ophidiomyces ophidiicola (Oo), the primary cause of Ophidiomycosis, is a fungal pathogen recently detected in Texas snakes. Prior to this study, there were major knowledge gaps regarding Oo growth, spread, and suitable environmental conditions. This study filled those gaps using a field to bench approach involving sampling snakes across Texas, in vitro fungal growth, and ecological niche modeling. 103 snakes were sampled across Texas in 2023 and 2024 and six cases of Oo infection were detected. Results of the growth experiment suggest that Oo prefers more stable temperatures and high humidity to a point and that there is a …

Fatal Disseminated Toxoplasmosis In Captive Red Kangaroo (Macropus Rufus) And Parma Wallaby (Macropus Parma): Pathological And Immunohistochemical Investigations, Sawang Kesdangsakonwut

The Thai Journal of Veterinary Medicine

Abstract

Toxoplasmosis is a protozoan zoonosis caused by Toxoplasma gondii. Marsupials are considered a susceptible intermediate host. T. gondii is mainly transmitted to intermediate hosts via the fecal-oral route. A captive red kangaroo was diagnosed with disseminated toxoplasmosis based on clinicopathological and immunohistochemical (IHC) investigations. Two years later, a five-year-old Parma wallaby was kept in the same area as the red kangaroo and showed clinical signs of depression, withdrawal from the troop, and weakness. The wallaby died within two days after showing the clinical signs. Pathological findings in this wallaby were compatible with disseminated toxoplasmosis. Tachyzoites and tissue cysts …

Chronic Guillain-Barré Syndrome From Misdiagnosed Lyme Disease, Carlos H. Cisneros Jr, Alberto E. Almeida

MEDI 9331 Scholarly Activities Clinical Years

Lyme disease (borreliosis) is caused by transmission of Borrelia burgdorferi from deer ticks in the United States. Neurological symptoms can manifest in the early disseminated stage of the disease and have the worst involvement in the late dissemination stage. Few, but important case reports exist of patients experiencing disseminated Lyme with associated Guillain-Barre Syndrome (GBS). GBS manifests as an ascending flaccid paralysis with additional sensory deficits and is characterized as an immune-mediated polyneuropathy attacking the peripheral nervous system. A college-aged, wheelchair bound, quadriplegic female presented to the clinic to establish care in October 2023. She reported being bitten by a …

Immunoregulatory Properties Of Immune Cells That Associate With The Lens Capsule Surface During Acute And Resolution Phases Of Experimental Autoimmune Uveitis, Phuong M. Le, Mary J. Mattapallil, Rachel R. Caspi, Mary Ann Stepp, A. Sue Menko

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Inflammation in the eye is tightly regulated to prevent vision impairment and irreversible blindness. Emerging evidence shows that immune cells are specifically recruited to the lens capsule in response to autoimmune uveitis, yet the potential that they have a role in regulating this inflammatory disease remained unexplored. Here, an immunolocalization approach combined with high-resolution confocal microscopy was used to investigate whether the immune cells that become stably associated with the lens capsule in the eyes of C57BL/6J mice with experimental autoimmune uveitis (EAU) have an immunoregulatory phenotype. These studies revealed that during the acute phase of uveitis, at day 18 …

Protective Immunity Of The Pore-Forming Domains Of Actinobacillus Pleuropneumoniae Apx Toxins In A Mouse Model, Kamonpun Chuekwon, Li-Ting Cheng, Chun-Yen Chu

The Thai Journal of Veterinary Medicine

The hemolytic/leukolytic toxins ApxI, II, and III play a central role in the pathogenicity of Actinobacillus pleuropneumoniae and may serve as effective vaccine antigens. However, since these toxins are large in size, we aimed to determine whether only the pore-forming domain of the toxins may be sufficient for protective immunity. Mice were vaccinated with the pore-forming domains for immune response analysis and challenge test. Significant antibody response was observed for the ApxI and II vaccine groups. For cellular immune response, CD4⁺ and CD8⁺ T cell expansion was observed for ApxI. Pro-inflammatory cytokine (IL-1b, IL-6) and T_H2-type …

Discovery Of Chicken Proventricular Necrosis Virus From Transmissible Viral Proventriculitis Outbreak In Broilers, Thailand, ์Nantaporn Wandee, Preeda Lertwatchrasarakul, Thaweesak Songserm

The Thai Journal of Veterinary Medicine

Transmissible viral proventriculitis (TVP) is an infectious disease-causing retarded growth in chickens. In Thailand, many stunted chickens have been found on commercial broiler farms since 2017. Significant post-mortem lesions are found only in the proventriculus. This study aims to investigate the causative agents of TVP outbreaks focusing on chicken proventricular necrosis virus (CPNV), the possible significant cause of TVP. CPNV was reproduced in specific pathogen-free (SPF) chickens. Affected chickens that have undergone proventriculitis are CPNV-positive by RT-PCR and nucleotide sequencing followed by phylogenetic analysis. The result showed that proventriculitis could be experimentally reproduced by inoculation of proventricular homogenate obtained from …

The Role Of Southern Red-Backed Voles, Myodes Gapperi, And Peromyscus Mice In The Enzootic Maintenance Of Lyme Disease Spirochetes In North Dakota, Usa, Michael W. Dougherty, Nathan M. Russart, Robert A. Gaultney, Emily Marie Gisi, Haley M. Cooper, Lindsey R. Kallis, Catherine A. Brissette, Jefferson A. Vaughan

Biology Faculty Publications

Lyme disease has expanded into the Great Plains of the USA. To investigate local enzootic transmission, small mammals were trapped in two forested tracts in northeastern North Dakota during 2012 and 2013. Peromyscus mice and southern red-backed voles, Myodes gapperi, comprised over 90% of all mammals captured. One site was dominated by Peromyscus (79% of 100 mammals captured). At the other site, M. gapperi (59% of 107 mammals captured) was more abundant than Peromyscus (36%). Immature stages of two tick species parasitized small mammals: Dermacentor variabilis and Ixodes scapularis. Larval I. scapularis ectoparasitism was significantly higher on Peromyscus (81% …

Scaling Antimicrobial Resistance Surveillance Nationally: The Case Of The Fleming Fund In Kenya, Mitchelle Kasudi, Dishon Muloi, Murungi Maurice, Allan Azegele, Romona Ndanyi, Revathi Gunturu, Loice Ombajo, Emmanuel Tanui, Robert Onsare, Geoffrey Omuse

Pathology, East Africa

Rising levels of antimicrobial resistance (AMR) in both humans and animals have reached alarming levels and are being recognized as a serious incremental threat to global food security, animal health and public health. The One Health approach recognizes the interconnectedness of human, animal and environmental health, and that AMR can be spread between different species and environments. The Fleming Fund, a UK Overseas Development Aid program managed by the UK’s Department of Health and Social Care, aims to improve AMR and antimicrobial use (AMU) surveillance data in Africa and Asia by generating, sharing, and using data to improve antimicrobial use …

Analysis Of Antibiotic Sensitivity Patterns In Pasteurellaceae Family Isolates: A Microbial And Molecular Investigation, Jillian Barron

Honors Scholar Theses

Bacteria in the Pasteurellaceae family are known to cause disease in both human and animal species. Like all species of bacteria, the pathogens in the Pasteurellaceae family evolve and acquire antimicrobial-resistant traits. Antimicrobial resistance of bacteria is a significant public health concern, as treatment of resistant pathogens becomes more difficult, if not impossible, with current medical capabilities. In this project, phenotypic and genotypic analyses were performed on Pasteurellaceae family isolates sourced from the Connecticut Veterinary Medical Diagnostic Laboratory. Phenotypic antibiotic sensitivity patterns of each isolate were assessed against a panel of antibiotics through a Kirby-Bauer disk diffusion test. Disk diffusion …

Intervention Measures Alleviating Bacterial Chondronecrosis With Osteomyelitis In Broilers: Experimental Lameness And Feed Additive Treatments, Andi Asnayanti

Graduate Theses and Dissertations

As the global population grows, the supply and demand for meat have dramatically increased. The poultry industry has managed to satisfy the high demand for chicken meat through fast-growing broilers. The poultry breeder industry has successfully provided modern broilers with high liveability, feed efficiency, and processing yields through genetic selection of the traits of interest such as growth rate, feed conversion rate, and breast quality. Nevertheless, the intensive selection of modern broiler chickens for fast growth and feed efficiency leads to unintended side effects, such as excessive fat, low reproductive performance, leg abnormalities, low immunity, cardiovascular diseases, and metabolic disorders. …

Close Contacts Of Xenograft Recipients: Ethical Considerations Due To Risk Of Xenozoonosis, Daniel J Hurst, Luz Padilla, Daniel Rodger, Tamar Schiff, David K C Cooper

Rowan-Virtua School of Osteopathic Medicine Departmental Research

With decades of pre-clinical studies culminating in the recent clinical application of xenotransplantation, it would appear timely to provide recommendations for operationalizing oversight of xenotransplantation clinical trials. Ethical issues with clinical xenotransplantation have been described for decades, largely centering on animal welfare, the risks posed to the recipient, and public health risks posed by potential spread of xenozoonosis. Much less attention has been given to considerations relating to potentially elevated risks faced by those who may care for or otherwise have close contact with xenograft recipients. This paper examines the ethical and logistical issues raised by the potential exposure to …

Streptococcus Canis Native Aortic Valve Endocarditis Linked To Cat Exposure: A Case Report And Review, Michael S. Wang, Maria Huaringa, Lauren Feld, Ken Ochiai, Tiffany Whelan, Nicholas M. Frazier

Journal of Community Hospital Internal Medicine Perspectives

Streptococcus canis is an uncommon human pathogen, but documented infections have been mostly associated with exposure to dogs. There are only five documented cases of endocarditis secondary to streptococcus canis, with all cases except one documenting exposure to a canine. We present a 74-year-old male with a history of Type 2 diabetes mellitus, CKD 3, moderate aortic stenosis and remote exposure to agent orange, who was found to have Streptococcus canis native valve endocarditis without exposure to a dog. To the best of our knowledge this case is the first case of endocarditis linked to feline exposure.

Distribution Of Tick Species On Free-Ranging Ungulates In Northern New England, Karisa Graham

Honors Theses and Capstones

In Northern New England, ungulates are often parasitized by ticks, which is one of the leading causes for the decline in population. Ungulates are a good host for ticks, specifically deer ticks and winter ticks, and these ticks cause many tick-borne diseases in humans as well. The purpose of this study was to assess passive sampling from harvested animals as a means of tick surveillance in Vermont and New Hampshire. Ticks were collected from deer and moose and mapped throughout the two states by ArcGIS to visualize the trends in distribution. Relative abundance was greater in southeastern Vermont, with no …

The Effect Of Mating Pheromone 2,6-Dichlorophenol On Gene Expression In Male Lone Star Ticks (Amblyomma Americanum), Mitchell E. Dyen

Honors Undergraduate Theses

Lone star ticks (Amblyomma americanum) are tick species known for their generalist feeding habits, pursuing blood meals with little preference for specific host species. They are found in the southern and midwestern United States but have been rapidly expanding northward due to climate change and white-tailed deer population expansion. Since they are a zoonotic disease vector, their increased abundance has caused the concurrent increased prevalence of a variety of tick-borne illnesses such as tularemia, heartland virus disease, alpha-gal syndrome, ehrlichiosis, and southern tick-associated rash illness (STARI), which effect both humans and animals alike. This increased prevalence of tick-borne …

Dual Suppression Of Glossina Pallidipes Using Entomopathogenic Fungal-Based Biopesticides And Sterile Insect Technique, Fidelis L.O. Ombura, Adly M.M. Abd-Alla, Komivi S. Akutse, Steven Runo, Paul O. Mireji, Rosemary Bateta, Joseck E. Otiwi, Inusa J. Ajene, Fathiya M. Khamis

All Peer-Reviewed Publications

Tsetse flies and trypanosomosis significantly impact bovine production and human health in sub-Saharan Africa, exacerbating underdevelopment, malnutrition, and poverty. Despite various control strategies, long-term success has been limited. This study evaluates the combined use of entomopathogenic fungi (EPF) and the sterile insect technique (SIT) to combat tsetse flies. Eleven EPF isolates were tested against teneral males of Glossina pallidipes, focusing on mortality rates, radial growth, and impacts on fly fitness. Temperature effects on conidial growth, sporulation, and spore yield of SIT-compatible/tolerant strains were also assessed. The fungal isolates significantly influenced mortality rates in both unirradiated and irradiated (SIT-treated) males (p <  0.0001). Metarhizium anisopliae strains ICIPE 20, ICIPE 32, ICIPE 41, ICIPE 62, ICIPE 78, and Beauveria bassiana ICIPE 603 showed higher SIT compatibility/tolerance with LT50 values of 11–30 days, compared to other more virulent isolates with LT50 values of 4–9 days. Temperature significantly affected the radial growth of SIT-compatible EPF strains (p <  0.0001), with M. anisopliae ICIPE 78 exhibiting the fastest conidia growth at 25°C. Spore yield varied significantly across temperatures (15–40°C), and the thermal range for conidia germination of SIT-compatible strains was 8.1–45.4°C, with an optimal range of 26.7–31.1°C. Moreover, infected unirradiated females and irradiated males (donors) successfully transmitted conidia to untreated flies (receivers) without significant differences in survival rates (p = 0.6438) and no observed sex dimorphism. Our findings highlight the potential of combining EPF and SIT as a novel dual approach that could effectively and synergistically suppress tsetse fly populations.

Tissue-Specific Localization Of Tick-Borne Pathogens In Ticks Collected From Camels In Kenya: Insights Into Vector Competence, Rua Khogali, Armanda Bastos, Joel L. Bargul, Dennis Getange, James Kabii, Daniel Masiga, Jandouwe Villinger

All Peer-Reviewed Publications

Background: Tick-borne pathogen (TBP) surveillance studies often use whole-tick homogenates when inferring tick-pathogen associations. However, localized TBP infections within tick tissues (saliva, hemolymph, salivary glands, and midgut) can inform pathogen transmission mechanisms and are key to disentangling pathogen detection from vector competence. Methods: We screened 278 camel blood samples and 504 tick tissue samples derived from 126 camel ticks sampled in two Kenyan counties (Laikipia and Marsabit) for Anaplasma, Ehrlichia, Coxiella, Rickettsia, Theileria, and Babesia by PCR-HRM analysis. Results: Candidatus Anaplasma camelii infections were common in camels (91%), but absent in all samples from Rhipicephalus pulchellus, Amblyomma gemma, Hyalomma dromedarii, …

Human-Bat Interactions In A Disease Emergence Hotspot: Implications For Human Health And Bat Conservation, Reilly Tempest Jackson

Graduate Theses and Dissertations

Bats are an ecologically important taxon that can host zoonotic pathogens. Globally, many bat species are synanthropic and live closely with humans, often roosting in man-made structures. The spatial overlap between humans and bats creates opportunities for human-bat contact, which can lead to human exposure to bat-borne pathogens and conflicts that cause bat mortality. Despite this risk, little is known about the drivers and characteristics of these human-bat interactions in buildings and work is needed to understand this aspect of the wildlife-urban interface. In Chapter I, I present a literature review that identifies the geographic and taxonomic trends in reported …

Impacts Of Environmental Stressors On Native South Dakota Amphibian Physiology And Survival, Danielle Jean Galvin

Dissertations and Theses

Amphibian populations around the world are declining, with some of the most likely drivers behind these declines including emerging infectious diseases and environmental contaminants. To address major gaps in the current literature, I sought to evaluate the effect of two major environmental stressors on various aspects of amphibian physiology: emerging infectious diseases and environmental contaminants. Emerging infectious diseases of amphibians include fungal, viral, and parasitic pathogens which have expanded in host range, either geographically or in competent host species. Environmental contaminants include chemicals which may be naturally occurring in the environment, or which may be introduced to the environment, often …

Relative Hepatotoxocity, Carcinogenicity, And Toxicogenomics Of Select Dehydropyrrolizidine Alkaloids In Mice, Michael J. Clayton

All Graduate Theses and Dissertations, Fall 2023 to Present

Dehydropyrrolizidine alkaloids are arguably the most important plant derived toxins in terms of impact on human and animal health. Dehydropyrrolizidine alkaloids are a large group of chemically related compounds found in 3% of flowering plants worldwide. Human exposure occurs from ingestion of herbal products including teas supplements or contaminated grain. Animals are exposed through contaminated feed or grazing. There are at least 350 identified toxic PAs, from more than 6,000 plants. The toxins primarily cause liver damage, but some are proven to cause cancer. Indidvidual dehydropyrrolizidine alkaloids vary in their toxic effects. Riddelliine is the only dehydropyrrolizidine alkaloid with extensive …

Transferability Of Tsetse Habitat Models Between Different Regions In Kenya And Rwanda, Stella Gachoki, Anton Vrieling, Thomas A. Groen, Andrew Skidmore, Daniel Masiga

All Peer-Reviewed Publications

Accurate and reliable information on the distribution of tsetse habitats is crucial for the effective management of African Trypanosomiasis in sub-Saharan Africa. However, conducting large-scale surveillance of tsetse flies to develop distribution maps is impractical due to vast areas infested and limited resources available. To address this challenge, we evaluated the applicability of tsetse habitat models developed in the intensively sampled Shimba Hills National Reserve in Kenya for both the wet and the dry season, to two other regions in Kenya (Ruma National Park and Nguruman Conservancy) and one region in Rwanda (Akagera National Park). The models utilized satellite-based estimates …

Evaluation Of The Virulence Potential Of Avian Pathogenic Escherichia Coli Isolated From Broiler Breeders With Colibacillosis In Mississippi, Jiddu Joseph

Theses and Dissertations

Avian pathogenic Escherichia coli (APEC) is a bacterium that is responsible for colibacillosis in birds. However, information about broiler breeder APEC isolates is limited, but the data is critical due to the transfer of this bacteria down the production pyramid to progenies resulting in high mortality. Therefore, we evaluated the phenotypic virulence characteristics of 28 isolates using embryo lethality and day-old chick challenge assays. Also, the in vitro adhesion and invasion potential of selected nine isolates were identified. Results showed more than 1/3^rd of the isolates were highly virulent and the virulence increased as the number of virulence-associated genes …

Investigation Of Orthohantavirus Genetics In Rodent Reservoirs And Clinical Samples, Samuel Melvin Goodfellow

Biomedical Sciences ETDs

Orthohantaviruses are negative-sense, single stranded RNA viruses with trisegmented genomes that can cause severe disease in humans and are carried by several host reservoirs throughout the world. In the United States, Sin Nombre orthohantavirus (SNV) is the primary cause of hantavirus cardiopulmonary syndrome (HCPS) with a fatality rate of ~36% and the highest cases occuring in the southwest region. The primary SNV host reservoir is thought to be the western deer mouse, Peromyscus maniculatus, however it has been shown that other rodents can carry different orthohantaviruses. We designed a pan-orthohantavirus detection tool to survey several small mammal populations throughout New …

Extrinsic Allergic Alveolitis: A Systematic Review Of Hla-Dr In Pigeon Breeder’S Disease, Dylan Thibaut, Ryan A. Witcher, Anitha Kunnath, James Toldi

Advances in Clinical Medical Research and Healthcare Delivery

Abstract

Introduction: Pigeon Breeder’s Pneumonitis (PBP) results due to a complex pathophysiology that includes exposure to avian antigens. Susceptibility has been linked to human leukocyte antigen (HLA) class II, though consensus has not been reached. The goal of this systematic review is to further elucidate the association between PBP and HLA-DR subtypes.

Methods: Databases utilized included PubMed, Google Scholar, ScienceDirect, and Cochrane Library. Inclusion required a minimum of three studies in English presenting HLA-DR alleles of PBP and control subgroups. Exclusion was due to insufficient data or non-feasible control groups. Forest plots were created for HLA-DR subtypes’ association …

Effect Of Use Of Tsetse Repellant Collar Technology On The Farm Performance And Household Welfare Of Small-Scale Livestock Farmers In Kenya, Beatrice W. Muriithi, Kassie Menale, Gracious M. Diiro, Michael N. Okal, Daniel K. Masiga

All Peer-Reviewed Publications

Tsetse-transmitted Animal African Trypanosomosis (AAT) is a disease of economic importance to livestock development in Sub-Saharan Africa. The disease is widely managed using trypanocides that are expensive for smallholders and associated with health risks due to drug residues in animal products and drug resistance. Developed recently by the International Centre of Insect Physiology and Ecology (icipe) and partners, the novel Tsetse repellent collar technology (TRCT) provides an effective alternative control measure that targets the tsetse fly vector of AAT. This study assessed the impact of TRCT on household welfare and food security by using ex-post non-experimental data obtained from 632 …

Whole Genome Sequencing Of West Nile Viruses From Animals Submitted To The Connecticut Veterinary Medical Diagnostic Laboratory (Cvmdl), Usa, 2021, Allison Appel

Honors Scholar Theses

West Nile Virus (WNV) causes a zoonotic disease. WNV was first isolated in Uganda in 1937 and has since become an endemic in countries such as North, South, and Central America [1]. According to the Connecticut Department of Public Health, an average of 8 cases of WNV in humans have been reported since the year 2000 [2]. In this study, we focused on the genetic characterization of the viral genomic RNA of WNVs circulating in birds and mammals in the New England region. Following that aim, the complete genome sequence of two WNVs was obtained via next-generation sequencing. One sample …

Evolution And Epidemiology Of Channel Catfish Virus (Ccv), Arun Venugopalan

Theses and Dissertations

Channel catfish virus disease (CCVD) is the principal viral disease in the United States catfish industry. The CCVD is caused by channel catfish virus (CCV), with mortality reaching up to 100% in fingerlings. CCV is assigned taxonomically to the family Alloherpesviridae, genus Ictalurivirus, species Ictalurid herpesvirus 1 (IcHV-1). To date, virulence, immunogenicity, and genome plasticity of the CCV field isolates have not been investigated. Three genotypes of CCV (IcHV-1A, IcHV-1B, and BCAHV) were identified using restriction fragment length polymorphism (RFLP) analysis. Virulence assessment of three representative isolates of RFLP groups suggests that IcHV-1B (pooled survival [mean ± SE]: 58.3% ± …

Effect Of Temperature On The Microbiome Of A Laboratory Reared Colony Of Haemaphysalis Longicornis Ticks, Brianna Mitchell

Poster Presentations

Honors research poster.

Haemaphysalis longicornis is a species of tick native to eastern Asia, including eastern China, Japan, eastern Russia, and Korea. To date, it has invaded and has now established its existence in Australia, New Zealand, and several of the Pacific Islands. This species of tick has recently been introduced to the United States, having a confirmed sighting in November 2017 on a sheep farm in New Jersey and since establishing populations in 18 states along the east coast and Appalachia. Based on the existing locations of H. longicornis in its native regions, as well as in the United …

An Ecological Perspective Of American Rodent-Borne Orthohantavirus Surveillance, Nathaniel Mull

Graduate Theses and Dissertations

Orthohantaviruses are a global group of viruses found primarily in rodents, though several viruses have also been found in shrews and moles. Many rodent-borne orthohantaviruses are capable of causing one of several diseases in humans, and the mortality associated with these diseases ranges from < 0.1% - 50% depending on the specific etiological virus. In North and South America, orthohantavirus research was ignited by an outbreak of severe disease in the Four Corners region of the United States in 1993. However, despite the discovery of over 20 orthohantaviruses in the Americas, our understanding of orthohantavirus ecology and virus-host dynamics in this region is still limited, and orthohantavirus surveillance is generally restricted in scope to select regions and small portions of host distributional ranges. In Chapter I, I present a literature review on the current understanding of American rodent-borne orthohantavirus ecology. This review focused on under-studied orthohantaviruses, addressing gaps in knowledge by extrapolating information from well-studied orthohantaviruses, general rodent ecology, and occassionally from Eurasian orthohantavirus-host ecology. There were several key conclusions generated from this review that warrant further research: 1) the large number of putative orthohantaviruses and gaps in orthohantavirus evolution necessitate further surveillance and characterization, 2) orthohantavirus traits differ and are more generalizable based on host taxonomy rather than geography, and 3) orthohantavirus host species are disproportionately found in grasslands and disturbed habitats. In Chapter II, I present a prioritized list of rodent species to target for orthohantavirus surveillance based on predictive modeling using machine learning. Probable orthohantavirus hosts were predicted based on traits of known orthohantavirus hosts using two different types of evidence: RT-PCR and virus isolation. Predicted host distributions were also mapped to identify geographic hotspots to spatially guide future surveillance efforts. In Chapter III, I present a framework for understanding and predicting orthohantavirus traits based on reservoir host phylogeny, as opposed to the traditional geographic dichotomy used to group orthohantaviruses. This framework establishes three distinct orthohantavirus groups: murid-borne orthohantaviruses, arvicoline-borne orthohantaviruses, and non-arvicoline cricetid-borne orthohantaviruses, which differ in several key traits, including the human disease they cause, transmission routes, and virus-host fidelity. In Chapter IV, I compare rodent communities and orthohantavirus prevalence among grassland management regimes. Sites that were periodically burned had high rodent diversity and a high proportion of grassland species. However, rodent seroprevalence for orthohantavirus was also highest in burned sites, representing a trade-off in habitat management outcomes. The high seroprevalence in burned sites is likely due to the robust populations supported by the high quality habitat resulting from prescribed burning. In Chapters V and VI, I describe Ozark virus and Sager Creek virus, two novel orthohantaviruses discovered from specimens collected during Chapter IV. Both chapters report full genome sequences of the respective viruses and compare both nucleotide and protein phylogenies with related orthohantaviruses. Additionally in Chapter VI, I support the genetic analyses with molecular and ecological characterizations, including seasonal fluctuations in host abundance, correlates of prevalence, evidence of virus shedding, and information on host cell susceptibility to Sager Creek virus.