About

Sarah Ozawa is a Clinical Assistant Professor at North Carolina State University in the College of Veterinary Medicine. She received her veterinary degree from the University of Wisconsin and completed a small animal rotating internship at the University of Tennessee. Following her internship, she completed an ACZM residency in zoological companion animal medicine at the University of California, Davis, and became board certified by the American College of Zoological Medicine in 2020. Her research interests include small mammal therapeutics and cardiovascular disease, contributing to the field through her clinical work and scholarly publications.

Research topics

• Medicine
• Internal medicine
• Surgery
• Cardiology
• Gastroenterology

Selected publications

• Rabbits with liver lobe torsion commonly exhibit gastric dilation, a rounded right hepatic silhouette, and peritoneal fluid on radiographs

  American Journal of Veterinary Research · 2026-01-26

  articleOpen accessSenior author

  Objective: To describe and quantify selected radiographic findings of rabbits diagnosed with liver lobe torsion (LLT). Methods: The study included 50 rabbits with an antemortem diagnosis of LLT with radiographs made within 72 hours of diagnosis via ultrasound. Medical records from 2010 to 2020 from 4 institutions were reviewed. A board-certified radiologist reviewed the radiographs. Radiographic evaluation of gastric size was assessed on the right lateral view (caudal extent of the stomach relative to the lumbar vertebral column, gastric height and width, and vertebral stomach score), as well as gastric content patterns and radiographic signs of intestinal dilation and content, hepatic rounding, and loss of serosal detail. Loss of abdominal serosal detail was compared to the presence of peritoneal fluid on ultrasound. Results: 35 of 50 rabbits (70%) had a gastric height and gastric width sum height greater than or equal to the length from the L1 cranial endplate to the coxofemoral joint. The median vertebral stomach score was 8.8. The gastric content was mostly ingesta. A rounded margin along the right hepatic silhouette in the ventrodorsal view was identified in 30 of 50 rabbits (60%). Peritoneal fluid was correctly identified radiographically in 37 studies (74%), not appreciated but present in 7 (14%), correctly identified as not present in 4 (8%), and incorrectly identified in 2 (4%). Conclusions: Radiographic findings suggested that gastric dilation with ingesta, a rounded right hepatic silhouette, and peritoneal fluid, although not always present, are common in rabbits with LLT. Clinical Relevance: Identification of these findings should prompt further diagnostic imaging.

  PublisherDOI

• Comparison of Intrarenal and Intravenous Injections of Sodium Pentobarbital for Euthanasia in New Zealand White Rabbits (Oryctolagus cuniculus)

  UNC Libraries · 2026-04-22

  articleOpen access

  Peripheral venous access in rabbits can be difficult to obtain. When failure occurs, there is a dire need for alternative vascular access routes to be available. The AVMA categorizes intrarenal injection of pentobarbital as acceptable with conditions for euthanasia. Animals must be in an unconscious state, and only minimal studies using intrarenal administration have been reported. A total of 53 rabbits were used to conduct 3 separate analyses to assess and measure the efficacy, efficiency, and validity of the intrarenal route for euthanasia in New Zealand White rabbits by assessing the time to cardiopulmonary arrest (TCPA). Animals were sedated with 40 mg/kg ketamine and 50 μg/kg dexmedetomidine intramuscularly into the lumbar muscles, and timing started at the beginning of the injection and ended when cardiac and respiratory arrest were observed. Cardiac and respiratory arrest following intravenous injection of pentobarbital was significantly quicker (cardiac, 6 to 24 s, median 9 s; respiratory, 6 to 19 s, median 9 s; P < 0.001) than for the intrarenal route (cardiac, 40 to 900 s, median 411 s; respiratory, 23 to 900 s, median 120 s; P < 0.001), with no negative animal reactions observed during euthanasia injection performance. Four animals did not achieve TCPA within 15 min after administration. Although TCPA was longer with intrarenal compared with intravenous euthanasia ( P < 0.001), this study demonstrates that the intrarenal approach under anesthesia is a feasible alternative to the intravenous approach, as it can be reliably performed without observed animal distress or alterations in organ pathology. The overall information from this study can help guide both laboratory and practicing clinicians considering this technique. Still, factors such as variable times to cardiopulmonary arrest and technical skill should be considered.

  PublisherDOI

• Determination of Cardiac Troponin I in Guinea Pigs (Cavia porcellus) under Different Restraint Methods and Using a Point-of-Care Assay or Laboratory Analyzer

  Journal of the American Association for Laboratory Animal Science · 2026-03-01

  article

  Guinea pigs are a commonly used model for laboratory research, as well as being housed in zoological institutions and kept as pets. These animals can develop cardiac disease, and additional diagnostic modalities are needed to help expediently and accurately diagnose it. Cardiac troponin I (cTnI) is a cardiac-specific biomarker associated with myocyte damage. The objectives of this study were to (1) determine the utility of a point-of-care (POC) cTnI assay in guinea pigs via cardiac and skeletal muscle tissue homogenates serially diluted in saline; (2) compare this POC assay to a high-sensitivity assay; and (3) determine the effect of restraint method (awake, isoflurane, and ketamine-xylazine) on cTnI measurements. A total of 45 guinea pigs were used in this study. Homogenates of cardiac muscle produced detectable concentrations of cTnI, while skeletal muscle homogenates did not. There was a significant difference between the POC (cTnI median 0.000 [range 0.000-0.0450] ng/mL) and the high-sensitivity (cTnI 0.025 [range 0.010-0.042] ng/mL) assays, suggesting that the former may require its own reference interval. There were no significant differences detected among the order of treatments (P = 0.66320), the method of restraint (P = 0.2315), or the interaction between the treatments (P = 0.9755); however, there were more nonzero values obtained for cTnI 7 days after anesthesia with ketamine-xylazine. These results suggest that this POC assay may be useful in the detection of cTnI in guinea pigs using a variety of restraint methods, although a high-sensitivity assay is recommended when low concentrations or small variations in concentration need to be detected.

  PublisherDOI

• Detecting cardiac troponin I (cTnI) in cardiac tissue of reptiles with two different immunoassays

  Journal of Exotic Pet Medicine · 2025-12-31

  articleOpen accessCorresponding

  Cardiac troponin I (cTnI), a cardiac-specific biomarker used to detect myocardial injury in mammals, has only undergone cursory investigation in reptiles. This study’s objectives were to determine feasibility of cTnI detection in reptilian cardiac tissue, skeletal muscle, and plasma utilizing two different immunoassays, and compare tissue concentrations between immunoassays and taxonomic groups (chelonians, lizards, snakes). Tissue homogenates were created and total protein concentrations determined from cardiac tissue and skeletal muscle collected from 30 individual reptiles representing 25 different species. Heparinized plasma was collected from seven reptiles. Samples were analyzed on both point-of-care (i-STAT) and high-sensitivity (ADVIA) immunoassays when feasible, and standardized concentrations compared between sample type, immunoassay, and taxonomic group. cTnI was detected above the lower limit of detection (LoD) in cardiac tissues from 24/25 species on the i-STAT and 22/22 species on the ADVIA. Only one sample produced analyzer error, occurring on the i-STAT. Cardiac tissue had significantly higher cTnI in chelonians ( p adj = 0.034) and lizards ( p adj = 0.049) than snakes on the i-STAT, and in chelonians than both lizards ( p adj = 0.015) and snakes ( p adj < 0.01) on the ADVIA. The i-STAT and ADVIA had poor agreement for cardiac tissue samples. Most skeletal muscle samples reported analyzer error (20/30) or concentrations below the LoD (9/30) on the i-STAT. On the ADVIA all skeletal muscle samples were above the LoD (25/25), and four snakes had higher cTnI concentrations in skeletal muscle than cardiac tissue. All plasma samples had detectable cTnI on both immunoassays, but most on the i-STAT were below the LoD. At least 22 reptile species have detectable cTnI in cardiac tissue on two different immunoassays. Due to variability between taxonomic groups and immunoassays, establishment of both species-specific and assay-specific reference intervals are warranted for clinical utility.

  PublisherDOI

• An Ocular Manifestation of a Systemic Disease With <i>Encephalitozoon Pogonae</i> in a Juvenile Central Bearded Dragon ( <scp> <i>Pogona vitticeps</i> </scp> )

  Veterinary Ophthalmology · 2025-09-16

  articleOpen access

  OBJECTIVE: Encephalitozoon pogonae, a recently identified microsporidian species, has been associated with systemic infections in Central bearded dragons (Pogona vitticeps) manifesting as granulomatous inflammation and vasculitis. Despite the species similarity to Encephalitozoon cuniculi, which causes ocular, neurologic, and renal pathology in rabbits, ocular manifestations of E. pogonae in bearded dragons are underreported. This case report aims to explore the ocular manifestations of E. pogonae in a clinical case and highlight the challenges in diagnosis and treatment of microsporidial infections in reptiles. ANIMAL STUDIED: A 6-month-old male central bearded dragon with initial presentation of unilateral blepharoconjunctivitis. PROCEDURES: The patient was treated with topical ofloxacin 0.3% ophthalmic solution, systemic nonsteroidal anti-inflammatories (meloxicam), and antimicrobials (ceftazidime). Diagnostic efforts included physical and ophthalmic examination, ocular high-frequency ultrasound (48 mHz transducer), cytological examination of conjunctiva, and histopathological examination with PCR analysis confirming E. pogonae in both liver and conjunctiva. RESULTS: Despite treatment, the patient died from hemopericardium. Necropsy demonstrated severe granulomatous inflammation in multiple organs, including the liver, intestines, and ocular structures (conjunctiva and uveal tissue), as well as hypermature cataracts and phacoclastic uveitis, consistent with systemic microsporidiosis. CONCLUSIONS: This case highlights the potential for an ocular manifestation of a systemic disease caused by E. pogonae, underscoring the importance of considering microsporidial infections in the differential diagnosis of refractory ocular disease in reptiles. The findings also emphasize the challenges in diagnosing and treating these infections.

  PublisherOA PDFDOI

• Clinical value of amylase and its prognostic accuracy in guinea pigs (<i>Cavia porcellus</i>)

  Journal of Small Animal Practice · 2025-02-25 · 1 citations

  articleOpen accessCorresponding

  OBJECTIVES: To retrospectively evaluate plasma amylase concentrations in client-owned guinea pigs (Cavia porcellus) and determine a possible association with mortality. MATERIALS AND METHODS: Medical records of guinea pigs that had a biochemistry panel from four institutions were retrospectively reviewed. Guinea pigs were excluded from the study if plasma amylase concentrations were not measured or there was no follow-up 30 days after the initial biochemistry panel. RESULTS: Two hundred seventy-eight guinea pigs were included. Odds of mortality were not linearly associated with increasing amylase concentrations, but higher mortality was seen with markedly elevated plasma amylase (1910 to 3985 U/L; 65.2% death). After multivariable adjustment, guinea pigs with markedly elevated plasma amylase concentrations were seven times more likely to die within 30 days compared to those with a concentration within the reference interval (1339 to 1573 U/L) (aOR: 7.98; adj. 95% CI: 3.29 to 19.35). In addition, BUN concentration higher than 62 mg/dL had a 29.97 times greater odds of 30-day mortality than those with a BUN concentration lower than 62 mg/dL (aOR: 29.97, adj. 95% CI: 3.78 to 237.65). The AUC of the ROC curve of amylase concentrations to predict 30-day mortality was 72.7% (95% CI: 65% to 79.9%). CLINICAL SIGNIFICANCE: While the exact pathophysiology of changes in plasma amylase concentrations in guinea pigs is unknown, this enzyme has clinical significance, considering that markedly elevated plasma amylase concentrations were associated with a higher risk of mortality. The actual prognostic capacity of the enzyme alone is limited and should be evaluated as part of a full clinical picture.

  PublisherOA PDFDOI

• Glossitis in four-toed hedgehogs (Atelerix albiventris): 7 cases (2003–2023)

  Journal of Exotic Pet Medicine · 2025-08-08

  article
  PublisherDOI

• Comparison of Intrarenal and Intravenous Injections of Sodium Pentobarbital for Euthanasia in New Zealand White Rabbits (Oryctolagus cuniculus)

  Journal of the American Association for Laboratory Animal Science · 2025-06-18

  article

  Peripheral venous access in rabbits can be difficult to obtain. When failure occurs, there is a dire need for alternative vascular access routes to be available. The AVMA categorizes intrarenal injection of pentobarbital as acceptable with conditions for euthanasia. Animals must be in an unconscious state, and only minimal studies using intrarenal administration have been reported. A total of 53 rabbits were used to conduct 3 separate analyses to assess and measure the efficacy, efficiency, and validity of the intrarenal route for euthanasia in New Zealand White rabbits by assessing the time to cardiopulmonary arrest (TCPA). Animals were sedated with 40 mg/kg ketamine and 50 μg/kg dexmedetomidine intramuscularly into the lumbar muscles, and timing started at the beginning of the injection and ended when cardiac and respiratory arrest were observed. Cardiac and respiratory arrest following intravenous injection of pentobarbital was significantly quicker (cardiac, 6 to 24 s, median 9 s; respiratory, 6 to 19 s, median 9 s; P < 0.001) than for the intrarenal route (cardiac, 40 to 900 s, median 411 s; respiratory, 23 to 900 s, median 120 s; P < 0.001), with no negative animal reactions observed during euthanasia injection performance. Four animals did not achieve TCPA within 15 min after administration. Although TCPA was longer with intrarenal compared with intravenous euthanasia (P < 0.001), this study demonstrates that the intrarenal approach under anesthesia is a feasible alternative to the intravenous approach, as it can be reliably performed without observed animal distress or alterations in organ pathology. The overall information from this study can help guide both laboratory and practicing clinicians considering this technique. Still, factors such as variable times to cardiopulmonary arrest and technical skill should be considered.

  PublisherDOI

• Colloidal-fibrillar composite gels demonstrate structural reinforcement, secondary fibrillar alignment, and improved vascular healing outcomes

  Communications Engineering · 2025-04-08 · 2 citations

  articleOpen access

  Many biological tissues contain colloids within a fibrillar structure. Here, we develop and characterize colloidal-fibrillar scaffolds through examination of the effects of relative colloid and fiber ratios within a fibrin-based model system composed of fibrin-based nanoparticles (FBNs) within a natural fibrin scaffold. At lower concentrations, FBNs primarily integrate into the fibrillar fibrin matrix, strengthening it. At high concentrations, colloid-colloid interactions dominate and FBNs primarily form a highly aligned secondary structure that does not strengthen the fibrillar matrix. At intermediate concentrations, both reinforcement of the fibrin matrix and colloid-colloid interactions are observed. Our characterization of this colloidal-fibrillar system provides insight into new avenues for wound healing biomaterial development. Using structural and mechanical results, we developed a biomimetic surgical sealant. When applied to a vascular healing model, FBN gel resulted in improved vessel healing. This colloidal-fibrillar composite can greatly improve healing outcomes and should be applied to other tissues. Nina A. Moiseiwitsch and colleagues develop and characterize a colloidal-fibrillar scaffold using fibrin-based nanoparticles to enhance matrix reinforcement and structural integrity. The findings offer new insights for biomaterial design, enabling a biomimetic surgical sealant that significantly improves vascular healing as well as other tissue repair applications.

  PublisherOA PDFDOI

• EVALUATION OF CARAPACIAL REPAIR TECHNIQUES FOR INJURED TURTLES PRESENTING TO A WILDLIFE CLINIC

  Journal of Zoo and Wildlife Medicine · 2025-06-05

  articleSenior authorCorresponding

  Chelonians commonly present to the North Carolina State University College of Veterinary Medicine's Turtle Rescue Team (TRT) for shell injuries. Several shell repair protocols are described in the literature, but many of these techniques are invasive, require a surgical plane of anesthesia, can result in infections or iatrogenic trauma, and are inaccessible in the wildlife rehabilitation setting. The objective of this study was to retrospectively evaluate three minimally invasive and inexpensive carapace fracture repair methods used at the TRT from 2012-2021. In total, 1,761 turtles presented with carapace fractures. Fracture repairs were performed in 428 turtles and were successful in 236 patients (55.1%). A successful outcome was defined as a fracture that was stable on manual palpation and the patient survived to release. The fracture did not stabilize but the subject survived to release in 13 cases (3.0%). Out of the repairs performed, there were 110 (25.7%) hook-and-wire procedures, 93 (21.7%) fragment removals, 94 (21.9%) marginal hole-and-wire repairs, and 131 (30.6%) repairs that included a combination of procedures. Success rates were highest for fragment removal (69.9%), followed by marginal hole- and-wire repairs (63.8%). The combined hook-and-wire procedures with fragment removal achieved a success rate of 57.9%, while hook-and-wire procedures alone saw a success rate of 47.3%. No complications arising from stabilization procedures were reported. The odds of success were significantly higher in adult males (OR = 3.904, 95% CI = 1.200, 12.705) and females (OR = 3.636, 95% CI = 1.087, 12.158) compared to juvenile turtles. A prognostic scoring system was developed based on published literature and clinical experience at TRT; the odds of success decreased as the prognosis moved from excellent to grave (OR = 0.330, 95% CI = 0.233, 0.458). These minimally invasive techniques should be considered in future chelonian fracture repairs.

  PublisherDOI

Frequent coauthors

• Molly Gleeson

  9 shared

• David Sánchez-Migallón Guzman

  University of California, Davis

  7 shared

• Michelle G. Hawkins

  4 shared

• Christian Munevar

  Eye Care Associates

  4 shared

• Gregory A. Lewbart

  North Central State College

  4 shared

• Olivia A. Petritz

  North Carolina State University

  4 shared

• Joanne Paul‐Murphy

  Zoological Society of San Diego

  4 shared

• Nicholas G. Dannemiller

  Sea Turtle Conservancy

  4 shared

Education

• Ph.D., Veterinary Science

  North Carolina State University

  2010

• M.S., Veterinary Science

  North Carolina State University

  2006

• Other, Veterinary Medicine

  University of California, Davis

  2004

• B.S., Animal Science

  University of California, Davis

  2000

Awards & honors

• Board Certified by the American College of Zoological Medici…