Lyme disease
Lyme diseaseIn the early 1970s, a mysterious clustering of arthritis occurred among children in Lyme, Connecticut, and surrounding towns. Medical researchers soon recognized the illness as a distinct disease, which they called Lyme disease. They subsequently described the clinical features of Lyme disease, established the usefulness of antibiotic therapy in its treatment, identified the deer tick as the key to its spread, and isolated the bacterium that caused it.
Lyme disease is still mistaken for other diseases, and it continues to pose many other challenges: it can be difficult to diagnose because of the inadequacies of today's laboratory tests; it can be troublesome to treat in its later phases; and its prevention through the development of an effective vaccine is hampered by the elusive nature of the bacterium.
Lyme disease was first recognized in 1975 after researchers investigated why unusually large numbers of children were being diagnosed with juvenile rheumatoid arthritis in Lyme and two neighboring towns. The investigators discovered that most of the affected children lived near wooded areas likely to harbor ticks. They also found that the children's first symptoms typically started in the summer months coinciding with the height of the tick season. Several of the patients interviewed reported having a skin rash just before developing their arthritis, and many also recalled being bitten by a tick at the rash site.
Further investigations resulted in the discovery that tiny deer ticks infected with a spiral-shaped bacterium or spirochete (which was later named Borrelia burgdorferi) were responsible for the outbreak of arthritis in Lyme.
In Europe, a skin rash similar to that of Lyme disease had been described in medical literature dating back to the turn of the century. Lyme disease may have spread from Europe to the United States in the early 1900s but only recently became common enough to be detected.
The ticks most commonly infected with B. burgdorferi usually feed and mate on deer during part of their life cycle. The recent resurgence of the deer population in the northeast and the influx of suburban developments into rural areas where deer ticks are commonly found have probably contributed to the disease's rising commonness.
The number of reported cases of Lyme disease, as well as the number of geographic areas, in which it is found, has been increasing. Lyme disease has been reported in nearly all states in this country, although most cases are concentrated in the coastal northeast, Mid-Atlantic States, Wisconsin and Minnesota, and northern California. Lyme disease is endemic in large areas of Asia and Europe. Recent reports suggest that it is present in South America, too.
Ticks that Most Commonly Transmit B. burgdorferi in the U.S.
(These ticks are all quite similar in appearance.)
� Ixodes dammini
-most common in the northeast and midwest
� Ixodes scapularis
-found in south and southeast
� Ixodes pacificus
-found on west coast
Erythema Migrans. In most people, the first symptom of Lyme...
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