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Mary Anna   Thrall DVM, MS, DACVP

Professor of Clinical Pathology

Dr. Mary Anna Thrall was a small animal practitioner for four years after receiving her DVM degree. Following her residency in clinical pathology, she was a faculty member in the Department of Pathology at Colorado State University for 32 years, where she helped train 42 veterinary clinical pathologists. She joined RUSVM in 2010 as a full time Professor of Veterinary Clinical Pathology. She is active in continuing education to veterinarians and pathologists and has provided more than 300 scientific presentations and continuing education programs. She is author or co-author of numerous scientific publications, abstracts, proceedings, and book chapters, and is the primary author of a clinical pathology textbook, Veterinary Hematology and Clinical Chemistry.



BA University of Evansville

DVM Purdue University

MS Colorado State University Clinical

(Residency) Colorado State University



Dr. Thrall's research interests over the last 30 years have been in the areas of bone marrow transplantation as therapy for feline models of lysosomal storage disorders, characterization of feline models of lysosomal storage diseases, including the mucopolysaccharidoses and Niemann Pick C1 disease, and treatment of ethylene glycol toxicosis in dogs and cats. Her current area of research is the role of lymphocytes in canine monocytic ehrlichiosis.


She served as the president of the American College of Veterinary Pathologists (2006-2007) and The American Society for Veterinary Clinical Pathology (1984-1985). She also served as Head of the Department of Biomedical Sciences at RUSVM for three years.

Dr. Thrall’s awards include the Association for Women Veterinarians Distinguished Service Award (1987), a CSU Distinguished Faculty Award (1988), the Purdue University School of Veterinary Medicine Distinguished Alumna Award (2004) and the American Society for Veterinary Clinical Pathology Lifetime Achievement Award, 2008. She was named a “Pillar of Pathology” by the American College of Veterinary Pathologists in 2012, and was the recipient of the National Pfizer (Zoesis) AAVMC Distinguished Teaching Award, in 2013.

Publication Highlights

Keirstead ND, Brake JW, Griffin MJ, Halliday-Simmonds I, Thrall MA, Soto E: Fatal septicemia caused by the zoonotic bacterium Streptococcus iniae during an outbreak in Caribbean reef fish. Vet Path, June 2013

Stimmelmayer R, Stefani LM, Thrall MA, Lander K, Revan F, Miller A, Beckstead R, Gerhold R..Trichomonosis in free-ranging Eurasian collared doves (Streptopelia decaocto) and African collared dove hybrids (Streptopelia risoria) in the Caribbean and description of ITS-1 region genotypes. Avian Dis. 2012 Jun;56(2):441-5. PMID: 22856210

Thrall MA, Weiser MG, Allison R, Campbell T. Veterinary Hematology and Clinical Chemistry, 2nd edition. Wiley-Blackwell. 2012.

Connally HE, Thrall MA, Hamar DW. Safety and efficacy of high-dose fomepizole compared with ethanol as therapy for ethylene glycol intoxication in cats. J Vet Emerg Crit Care. Apr 2010;1:20(2):191-206.

Somers KL, Royals MA, Carstea ED, Rafi MA, Wenger DA, Thrall MA. Mutation analysis of feline Niemann-Pick C1 disease. Mol Genet Metab. 2003;79:99-103.

Somers KL, Brown DE, Allison RA, Fulton R, Just C, Connally HE, Mitchell TW, Schultheiss P, Hamar D, Wenger DA, Thrall MA. Effects of dietary cholesterol restriction in a feline model of Niemann-Pick type C disease. J Inherited Metabolic Disease. 2001;24:427-436.

Connally HE, Thrall MA, Forney SD, Grauer, GF, Hamar DW. Safety and Efficacy of 4-methylpyrazole as treatment for suspected or confirmed ethylene glycol intoxication in dogs: 107 cases. (1983-1995). J Am Vet Med Assoc. 1996;209:1880-1883.

Brown DE, Thrall MA, Walkley SU, Mitchell TW, Wenger DA, Smith MO, Royals KL, March P. Animal Model of Human Disease: Feline Niemann-Pick Type C. Am J Pathol. 1994;144:1412-1415.

Colgan SP, Thrall MA, Gasper PW, Gould DH, Rose BJ, Fulton R,Blanquaert AMB, Bruyninckx WJ. Reversal of Neutrophil Mobility Defect and Platelet Pool Deficiency in Feline Chediak-Higashi Syndrome with Bone Marrow Transplantation. Bone Marrow Transplantation. 1991;7:101-110.

Gasper PW, Thrall MA, Wenger DA, Macy DW, Ham L, Dornsife RE, Quackenbush SL, Kesel ML, Gillette EL, Hoover EA. Correction of Feline Arylsulfatase B Deficiency (Mucopolysaccharidosis VI) by Bone Marrow Transplantation. Nature. 1984;312:467-469.


Determining hematologic and biochemical reference intervals in the Indian Mongoose.
Characterizing lymphocyte responses in dogs with monocytic ehrlichiosis.



Diplomate, American College of Veterinary Pathology (Clinical Pathology)