Disclaimer: The foregoing information is for educational purposes only. It is not intended to replace or supersede patient care by a healthcare provider. If an individual suspects the presence of a tick-borne illness, that individual should consult a healthcare provider who is familiar with the diagnosis and treatment of tick-borne diseases.
Lyme disease was first recognized in the United States in 1975 by Dr. Allen Steere, following a mysterious outbreak of juvenile rheumatoid arthritis near the community of Lyme, Connecticut. The rural location of the Lyme outbreak and the onset of illness during summer and early fall suggested that the transmission of the disease was by an arthropod vector.
In 1982, the etiologic agent of Lyme disease was discovered by Willy Burgdorfer, who isolated spirochetes belonging to the genus Borrelia from the mid-guts of Ixodes ticks. He showed that these spirochetes reacted with immune serum from patients that had been diagnosed with Lyme disease. Subsequently, the etiologic agent was given the name Borrelia burgdorferi. Since then, reports of Lyme disease have increased dramatically to the point that the disease has become an important public health problem in some areas of the United States. Today, Lyme disease is the most prevalent tick-borne illness in the United States.
Borrelia burgdorferi, like the human pathogen Treponema pallidum, is a spirochete. Spirochetes are a group of phylogenetically-distinct bacteria that have a unique mode of motility by means of axial filaments (endoflagella). Spirochetes are widespread in viscous environments and they are found in the intestinal tracts of animals and the oral cavity of humans. The spirochetes have a unique cell surface which accompanies their unique type of motility. The endoflagella are contained within the periplasmic space between a semi rigid peptidoglycan helix and a multi-layer, flexible outer membrane sheath. When the filaments rotate within this space, the spirochetes move in cork-screw fashion. This type of movement is thought to be an adaptation to viscous environments, such as aquatic sediments, biofilms, mucosal tissues and the intestinal tracts of animals. For pathogens, this allows the spirochetes to hide their flagella, which are normally antigenic, from the host immune defenses.