Section 2: Background in Borrelia burgdorferi and Lyme Disease

   Lyme disease (LD) is a complex and potentially persistent or chronic condition that may affect the human host in many ways. LD is classically described as involving musculoskeletal, neurological (both brain and peripheral nervous system), and cardiac systems, and, while this is largely true, it only begins to tell the story. LD is caused through infection by a bacterium, Borrelia burgdorferi (Bb), which is a mobile, spiral-shaped bacterial organism (see photo below) called a spirochete. Bb consists of a cluster of genotypically and phenotypically divergent isolates collectively referred to as Borrelia burgdorferi sensu lato. In this cluster, three species, B. burgdorferi sensu stricto, B.afzelii, and B.garinii., have been identified as vectors for human illness. Bb sensu stricto is the only species known to exist in North America and hundreds of strains have been isolated.
   Lyme disease was recognized in 1975 and the name derived from Lyme, Connecticut, the site of an epidemiological investigation of an outbreak of arthritis in adolescents at that time. The researchers included Dr. Allen Steere, a former CDC officer, who was working at Yale University in the Rheumatology section during that period. As cases accumulated and time passed, several parents, dissatisfied and alarmed with the diagnoses and treatments provided by their children's physicians, began to clamor for more definitive action. In large part due to their efforts, Steere and others were dispatched to Connecticut by the CDC to evaluate this outbreak of disabling arthritis. In time, the researchers suspected that an unidentified infectious agent was the culprit and reasoned that it may be tick-borne due to a recurring theme of patient reports of tick bites. In 1977, Dr. Steere and colleagues at Yale University published their work, describing children of that area who had recurrent joint swelling in this epidemic, and so termed this "new" clinical entity as "Lyme Arthritis"(8). By 1979, after further study, these researchers realized that there was a great deal more to this illness than just inflammatory arthritis. Specifically, they began to record the incidence of a characteristic expanding rash termed erythema migrans (EM), which occurred in most of their cases. Other symptoms, primarily neurological and cardiac, also became better recognized. On the basis of this information, Steere and colleagues decided to rename the clinical entity "Lyme Disease", and continued to claim it as a new clinical entity. Later, many European academicians would object to Steere's claim for primary discovery by stating that the clinical picture of "Lyme Disease" had been recognized on their continent for decades, perhaps centuries.

   In 1981, Dr. "Willie" Burgdorfer at the National Institute of Allergy and Infectious Disease (NIAID) discovered the microbial spirochete which proved to belong to the genus Borrelia (hence the name Borrelia burgdorferi) and the family Spirochaetaceae (which also includes the agents for syphilis, leptospirosis, and relapsing fever, among others). A year later Bb was isolated from the deer tick at the Rocky Mountain laboratory of the NIAID. Subsequently, the genomic characteristics of Bb have been elucidated and revealed as a single chromosome and several plasmids, both linear and coiled variety. Important and highly immunogenic surface proteins termed OspA and OspC have been identified and these proteins are recognized to be highly variable and capable of changing or mutating under different conditions. OspA is a critical factor in survival in the tick gut, whereas OspC becomes the dominant antigen in the human.

   The origin of Bb is unknown, although it is pertinent to note that Lyme-like dermatological lesions have been described for centuries in Europe. Some then speculate that Bb migrated to America from Europe on a stowaway rodent. Others doubt that Bb could have been here with the pilgrims because there is no record of erythema migrans, etc. In response, we suspect that colonial America was more concerned with the British and dysentery, not necessarily in that order. Undoubtedly, Bb has been around in various forms for centuries, although there may never be factual evidence to support this notion. As is the case with other zoonoses, the human is an accidental host, and is the worse for it.

   Over 100,000 cases of LD have been reported to the CDC. It is understood de facto that reports of various diseases to the CDC are underreported, but LD may be the all time winner for underreporting, so far as we are concerned. We believe that up to 90% of cases are unrecognized and/or unapparent to the host. By this, we do not mean to imply that these infections are insignificant, because chronic forms of Bb infection may follow and cause significant morbidity. When, in fact, Bb becomes chronic, or persistent, many authorities refer to the illness as neuroborreliosis, due to the acknowledged tropism of Bb for nervous tissue, whether it is glial cells or neurons. One impressive report stated that Bb presence in the cerebrospinal fluid after EM occurred in 67% of their cases. Not surprisingly, the eventual clinical presentation in persistent LD often portrays a major neurological disorder, undoubtedly the most severe manifestation of this illness. Some of these neurological syndromes mimic the pattern of findings one would expect to find in patients with multiple sclerosis (MS) or amyotrophic lateral sclerosis (ALS). In fact, it is well known that many neuroborreliosis victims have been mistaken for MS or, less commonly ALS, before the correct diagnosis was rendered.

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