Lyme disease is the most common vector-borne bacterial disease in the U.S., with 200,000 new cases each year. While incidence in Kentucky typically has been relatively low, the incidence of the tick vector, lxodes scapularis, has increased over the past five years, even spreading to areas it did not previously live.

Brian Stevenson, PhD, is a professor of microbiology, immunology, and molecular genetics at the University of Kentucky College of Medicine who has researched Lyme disease since 1992. He recently received two grants from the National Institutes of Health (NIH) to study potential treatments for Lyme disease as its vector spreads.

The grants, which began this spring, include a $3 million R01 grant over four years and a $400,000 R21 grant over two years. The funding will allow for the study of mechanisms by which the Lyme disease bacterium, Borrelia burgdorferi, senses when it is inside a human patient and undergoes adaptations to cause long-term infection.

“Our goal is to understand how Borrelia burgdorferi is able to persistently infect humans and other mammals and to cause Lyme disease,” Dr. Stevenson said. “Understanding the bacteria’s infectious mechanisms is revealing important points that can be targeted by new antibiotic therapies.”

Dr. Stevenson said Borrelia burgdorferi “knows” whether it’s inside a human or inside a tick. It responds to environmental cures by producing proteins and other factors that permit survival in that environment, while also suppressing production of inappropriate substances.

“If we can understand how the bacteria senses its environment and responds in a way that permits human infection, we can develop treatments that trick the bacteria into ‘thinking’ it is inside a tick instead of a human,” he said. “The bacteria would then stop doing what is needed to cause human infection, which will make it easier for the patient’s immune system to kill the bacteria.”

Dr. Stevenson’s latest research will center on three regulatory proteins – SpoVG, PlzA, and DnaA -- which are essential to the bacteria’s regulatory networks.

The work involves researchers across academic institutions. Dr. Stevenson is the principal investigator working with faculty from East Carolina University, the University of Kansas, the University of North Dakota, and Bates College. The colleagues speak monthly via Zoom to discuss updates.  

His lab also includes two PhD graduate students and one MS student and research analyst.

Dr. Stevenson’s recent grants build upon his two-plus decades of work to determine the regulatory pathways that control Borrelia burgdorferi gene expression. He has been at UK since 1998 and has published more than 90 peer-reviewed research papers, most of which are focused on Lyme disease and Borrelia burgdorferi.

His work studying Lyme disease and the tick vector extends across UK’s campus with an ongoing project involving the UK Department of Entomology to survey the state of Kentucky for tick species. He says the tick that vectors Borrelia burgdorferi is now being found in areas it was previously unseen.

In the future Dr. Stevenson plans to study infection levels throughout Kentucky and to culture the bacteria from Kentucky ticks to determine their potential for spreading infection.

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