Lyme disease is the most prevalent vector-borne infection in the temperate climates of North America and Eurasia. As many as half a million new infections are thought to occur every year in the United States alone. Presentations range from skin rashes and flu-like symptoms to serious and sometimes debilitating neurological, cardiac, and articular manifestations.
Lyme disease is caused by a spirochete bacterium, Borrelia burgdorferi. It is a highly unusual and fascinating bacterium. While the spirochetes all possess unique internal organization, with a bundle of flagella trapped between an inner and outer membrane, B. burgdorferi displays numerous other functional and organizational peculiarities. Prominent among these oddities is B. burgdorferi’s highly segmented and mostly linear genome; both characteristics are uncommon among bacteria. Multiple copies of a linear chromosome and about 20 either linear or circular plasmids are packed inside each spirochete cell. We are investigating how this unusual genome directs the successful completion of the spirochete’s tick-vertebrate transmission cycle.
We are also investigating the Lyme disease vector, the deer tick, Ixodes scapularis. Unlike their better studied vector counterparts, the mosquitos, ticks are not insects. Rather, they are acarids and are more closely related to spiders than insects. Yet ticks are vectors of several pathogens, including bacterial, viral, and parasitic disease agents. We endeavor to advance the knowledge of tick biology and to understand the vector’s organization, function, and the processes that generate an environment that allows for the survival and successful transmission of B. burgdorferi to new vertebrate hosts.