Feline Upper Respiratory Disease (FURD) is a complex disease characterized by, but not limited to, conjunctivitis, rhinitis, and tracheitis. Several pathogens encompass this disease including Feline Rhinotracheitis Virus (FHV), Feline Calicivirus (FCV), Chlamydophila felis (C. felis) , Bordatella bronchiseptica (B. bronchiseptica) , and Mycoplasma felis (M. felis) . This disease process significantly effects cats in group housing situations such as animal shelters and is a leading cause of morbidity and mortality in these cats. Previous research has investigated the epidemiology of pathogens and risk factors in several geographical areas, the development of molecular diagnostic tools for the detection of pathogens, and the detection of previously unreported pathogens in this complex. This thesis encompasses three papers meant to address the objectives of atypical Mycoplasma detection in cats with and without FURD, validation of a field deployable molecular device for pathogen detection, and an overall epidemiologic evaluation of the unique Midwestern geographical area. The first paper investigated the hypothesis that Mycoplasma species occur in the cat at higher levels of diversity than previously appreciated utilizing the unique molecular based Pan –Myco SYBR qPCR assay for the detection of the Mycoplasma genus and may be contributing to FURD. Overall, 15 Mycoplasma species were detected including: M. gateae/canadense/arginini cluster, M. canis, M. hyorhinis, M. alkalescens, M. cynos, M. faucium, M. dispar, M. buccale, M. spumans, M. hominis, M. bovis, M. bovoculi, M. maculosum/leopharyngis cluster, 2 new unknown species, and Acholeplasma laidlawii. Twelve of these Mycoplasma species were previously unreported in cats and several of these species are potential zoonotic pathogens. The second paper implemented a 5 stage pipeline for development and validation of field deployable assays utilizing the Insulated Isothermal Polymerase Chain Reaction (iiPCR) on the candidate field deployable device, POCKITTM for the detection of FURD including FHV, FCV, C. felis, M. felis, and B. bronchiseptica. Thirty of both positive and negative clinical samples and surrogate samples were randomized, blinded, and tested side-by-side on both platforms for each pathogen. Limits of detection were biologically relevant, were equal to or less than 10 infectious units, and demonstrated near equivalency with clinical samples for all pathogen targets. Exclusivity testing demonstrated the iiPCR to be pathogen and target specific. Sensitivity and specificity for clinical samples ranged from 80%–97% and 93–100% respectively. Kappa values ranging from 0.80–0.93 demonstrated strong agreement. Results demonstrate exceptional performance of the iiPCR reagents for detection of feline respiratory pathogens in clinical samples. This

Background: The 2024 Shelter Heartworm Management Practices Survey was performed to update current knowledge on heartworm management practices in animal shelters, including prevention, diagnosis, and treatment. Methods: The survey mirrored the 2019 survey with updates to questions based on new products and practices. The electronic survey was then distributed to veterinarians working with animal shelters in North America. Results: A total of 135 responses were received and distributed across private humane societies, municipal shelters, traditional shelters, breed/species-specific rescues, and foster-based organizations. Most organizations (77%) provided monthly heartworm preventives for dogs, using oral ivermectin products per label (50%), followed by oral milbemycin (33%). Shelters in the Midwest provided the highest percentage of heartworm preventives to both dogs and cats (37% and 40%), followed by the Southeast (31% and 34%). Heartworm testing was conducted in 76.2% of shelters for all dogs > 6 months of age, primarily using antigen testing (96.4%). Heartworm treatment was provided to all infected dogs in 66.1% of shelters. Those that only treated some dogs (22.9%) made treatment decisions based on adoptability (48.1%) and resources (25.9%). Primary adulticidal treatment was a three-dose melarsomine protocol (70.5%), followed by a two-dose melarsomine protocol (22.9%). A majority included doxycycline or minocycline and other common adjunctive treatments included steroids (75.3%) and macrocyclic lactones (60.2%). Heartworm-positive dogs were typically housed in the shelter (67%) or foster homes (49.5%) and made available for adoption. Exercise restrictions were applied in 80.6% of shelters, starting at diagnosis (55.8%) and continuing for several weeks after the last melarsomine injection (89.6%). During the restriction period, 58.2% of the shelters used psychopharmaceutical medications. Heartworm prevention was provided by 49.1% of shelters who admitted cats and 25.9% of those who admitted ferrets. Compared to 2019, shelter respondents reported increased use of preventives, microfilaria testing, doxycycline and three-dose melarsomine treatment for dogs, and a decrease in use of protocols for prevention of feline heartworm disease. Conclusions: Survey results highlight the challenges shelters have faced and the improvements made over the past 5 years, offering insights for targeted operational and educational improvements.