Faculty Profile

Thomas E. Besser

Thomas E. Besser

Professor and Rocky Crate-Wild Sheep Foundation Chair in Wild Sheep Disease Research

Epidemiology of zoonotic bacterial agents in their domestic animal reservoirs.
Office Phone: 509-335-6075 Lab Phone: 509-335-6086


My principal research focus is the epidemiology of zoonotic bacterial agents in their domestic animal reservoirs. In addition, I have recently been working on the etiology of bighorn sheep pneumonia.

I’m particularly interested in those agents that cause human food-borne diseases. The long-term goal of my research is the development of practical measures to reduce the prevalence of these agents in the animal reservoir as a means of reducing the risk of human disease.

While a great deal is known about how these agents act within the human host to cause disease, much less is known about their behavior in the animal reservoir(s) populations, which they typically colonize without evident signs of disease. If factors that influence the prevalence and dissemination of these agents can be identified, these factors might be manipulated to reduce human exposures to these dangerous agents.

I’m specifically interested in the role of clonal dissemination in the epidemiology of non-typhoid Salmonella and thermophilic Campylobacters, the interaction between the E. coli O157:H7 and their animal hosts and the environment and the relationship between antimicrobial resistance in Campylobacter and Salmonella bacteria and the use of antimicrobial drugs in animal husbandry.

Recently, I’ve begun working on a very different problem associated with cross-species transmission of pathogenic bacteria: epizootic pneumonia of bighorn sheep. This disease is strongly associated with Mycoplasma ovipneumoniae: North American wild sheep populations are normally free of this pathogen, but when infected are very susceptible to severe pneumonia that spreads through the population. For more information see: www.bighornhealth.org.