Veterinary Pathobiology

Kathryn Duncan, DVM, PhD, DACVM (Parasitology) is originally from Knoxville, Tennessee where she obtained her doctorate in veterinary medicine at The University of Tennessee. She completed her residency in veterinary parasitology through the National Center for Veterinary Parasitology and obtained a PhD in biomedical sciences at Oklahoma State University. In 2022, she became a diplomate of the American College of Veterinary Microbiologists, board-certified in Parasitology. Her research interests include emerging concerns in veterinary parasitology and vector-borne diseases of public health importance. 

Dr. Fouad S. Elmayet is currently a Research Assistant Professor in the Department of Veterinary Pathobiology at Oklahoma State University’s College of Veterinary Medicine. He holds a DVM and a master’s degree in Veterinary Virology. Dr. Elmayet completed his Ph.D. in Virology at Benha University, Egypt, in collaboration with Oklahoma State University, USA, in 2019. His doctoral research focused on herpesvirology. Following his Ph.D., Dr. Elmayet was appointed as a lecturer in the Department of Virology at Benha University’s College of Veterinary Medicine, where he taught virology to undergraduate and graduate students. During this time, he also conducted research on picornaviruses, including duck hepatitis A viruses and FMDV, as well as astroviruses. Dr. Elmayet later moved to the United States to pursue postdoctoral research with Dr. Clinton Jones at Oklahoma State University, concentrating on alpha-herpesvirus infections, particularly HSV-1 and BoHV-1. Dr. Elmayet’s current research focuses on elucidating the mechanisms by which alpha herpesviruses establish, maintain, and reactivate from latency in neurons, with the ultimate goal of developing a vaccine to prevent or eliminate herpesvirus latency. Dr. Elmayet is also a full member of the American Society for Virology and serves on the editorial boards of peer-reviewed journals, including Frontiers in Microbiology and BMC Veterinary Research.

Dr. Kelly S. Harrison is an Assistant Professor in the Department of Veterinary Pathobiology at Oklahoma State University’s College of Veterinary Medicine. She earned her MS at Oklahoma State University in Immunology in 2014 designing protein subunit vaccines against Gram-negative pathogens Shigella and Salmonella. Kelly completed her Ph.D. in Molecular Biosciences from the University of Kansas in 2017, where she studied the pathogenesis of Chlamydia species. Following her doctoral training, she pursued postdoctoral research with Dr. Richard Eberle and Dr. Clinton Jones at OSU, focusing on α-herpesvirus infections, including HSV-1, BoHV-1, and Monkey B virus.  

Dr. Harrison’s research explores sex-specific differences in STI pathogenesis, with a particular emphasis on the role hormones play during infectivity. Her work integrates multiple disciplines, investigating key cell signaling pathways in neurology, immunology, and cellular biology. With extensive expertise in microbiology, laboratory animal models, and drug/vaccine development, she is committed to advancing our understanding of host-pathogen interactions for development of innovative patient-centric therapeutic interventions.

Veterinary anatomic pathologist specializing in respiratory and zoonotic viral infections, host–pathogen interactions, and immunopathology. Experienced in diagnostic pathology, translational research, and contract pathology (CRO) support for preclinical safety and efficacy studies.

Theresa E Rizzi, DVM, Diplomate ACVP (Clinical Pathology), is a Clinical Professor and Department Head in the Department of Veterinary Pathobiology at Oklahoma State University, College of Veterinary Medicine. Originally from Brooklyn, New York, she obtained her undergraduate degree in biology from the State University of New York College at Old Westbury and her veterinary degree from Oklahoma State University in 1998. After several years in small animal private practice she accepted a position at OSU for a three year residency in Veterinary Clinical Pathology and achieved board certification in 2005. She became a faculty member in 2006.
She has co-authored two textbooks and numerous book chapters and journal articles.

Research Interests:

Her clinical interests include diagnostic cytology, hematology, and select infectious diseases.

Jennifer Rudd is a fully licensed veterinarian, educator and researcher with specialization in infectious diseases. After graduating with her doctorate in veterinary medicine from Oklahoma State in 2011, Dr. Rudd practiced small animal medicine and surgery (general practitioner) for several years before returning to her alma mater to pursue her doctorate in comparative biomedical sciences, with an emphasis on the innate immune response to pandemic influenzas and bacterial coinfections in people. Dr. Rudd is an assistant professor at OSU College of Veterinary Medicine and the interim Associate Dean for Academic and Student Affairs. She enjoys continuing to pursue her passions of teaching future veterinarians, researching infectious disease, and progressing innovative and effective education for future Oklahoma State veterinarians.

Research Interests:

* Translational animal models of acute SARS-CoV-2 infection
* The innate immune response and dysfunction after viral pneumonia
* Influenza pneumonias and bacterial coinfection
* Johne's Disease (Mycobacterium avium ssp paratuberculosis) in small ruminants
* Bovine respiratory disease complex
* Scholarship of teaching and learning
* Scholarship of scientific education

Dr. Joy Scaria is the Walter R. Sitlington Endowed Chair in Infectious Diseases and an Associate Professor in the Department of Veterinary Pathobiology at Oklahoma State University. He directs OSU’s Germ-Free and Gnotobiotic Core Facility, a university-level resource established to enable mechanistic microbiome research using gnotobiotic and humanized animal models. Prior to joining OSU, he served as a tenured faculty member at South Dakota State University, where he led major initiatives at the intersection of research, diagnostics, and workforce training.   His professional service includes elected leadership roles in the American Society for Microbiology, including service on the ASM Council of Microbial Sciences (COMS), which advises ASM’s Board on emerging scientific trends and growth opportunities across the microbial sciences. He is also an Honorary Diplomate of the American College of Veterinary Microbiology (ACVM), recognizing outstanding contributions to veterinary microbiology.

Research Focus

Research in the Scaria laboratory focuses on microbiome-guided strategies to improve human and animal health. The program emphasizes mechanistic studies and translation by integrating anaerobic culturomics, microbial genomics and metagenomics, defined microbial consortia, and gnotobiotic and humanized animal models with targeted metabolomics and immune phenotyping. These approaches enable identification of causal microbes, microbial pathways, and metabolites that shape host physiology and infection outcomes.

A major area of work is the development of defined bacterial consortia and engineered probiotics that enhance colonization resistance against enteric pathogens and support immune homeostasis. The laboratory designs and tests synthetic communities with controlled composition to dissect microbial interactions, resource competition, and metabolite cross-feeding that influence pathogen exclusion and community stability. In parallel, the group investigates microbiome-derived metabolites and microbial biotransformation products that modulate host defenses and antibiotic responses, with the goal of advancing deployable interventions for animal agriculture, including probiotic formulations, fermentation-derived bioactives, and microbiome-informed management strategies that reduce reliance on antibiotics.

A second area of focus treats antimicrobial resistance (AMR) as a systems problem in livestock-associated landscapes. This work connects host-associated microbiomes, waste streams, environmental dissemination, and downstream exposure pathways, leveraging interdisciplinary partnerships and data-driven modeling. The objective is to generate actionable evidence for AMR mitigation, from microbial targets and intervention points to decision tools that inform producer practices and public health strategies.