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On a warm, summer afternoon an 11-year-old girl presents having had low-grade fevers for 4 days and a rash. On physical examination, the pediatrician notes annular eruptions with erythema on her shoulder and legs (Figure 183-1). The mother states that the rash has gotten progressively larger during the last 3 days and her daughter complains of intermittent joint pain. She does not recall being bitten by an insect. She denies taking medications within the last month and has no known allergies. When asked about recent travel, the mother admits to taking the family on a camping trip in eastern Massachusetts with a return of 5 days ago. The patient was diagnosed with Lyme borreliosis (acute Lyme disease) and started on doxycycline 100 mg twice daily for 14 days. She responded quickly to the antibiotics and never developed the late stage of Lyme disease.
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Lyme disease is an infection caused by the spirochete Borrelia burgdorferi, transmitted via tick bite. Most cases of Lyme disease occur in the northeast between April and November. Patients experience flu-like symptoms and may develop the pathognomonic rash, erythema migrans. Lyme disease is prevented by avoiding exposure to the tick vector using insect repellent and protective clothing.
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In 1977, clusters of patients in Old Lyme, Connecticut, began reporting symptoms originally thought to be juvenile rheumatoid arthritis.1
In 1981, American entomologist, Dr. Willy Burgdorfer, isolated the infectious pathogen responsible for Lyme disease from the midgut of Ixodes scapularis (a.k.a., black-legged deer ticks; Figure 183-2), which serve as the primary transmission vector in the US.1
It was identified as a bacterial spirochete and named B. burgdorferi in honor of its founder.
Based on Centers for Disease Control and Prevention (CDC) data reported in 2007, Lyme disease (or Lyme borreliosis) is the most common tickborne illness in the US, with an overall incidence of 7.9 per 100,000 persons.2
In 2010, 94 percent of Lyme disease cases were reported from 12 states: Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, New Jersey, New Hampshire, New York, Pennsylvania, Virginia, and Wisconsin.3
Patients living between Maryland and Maine accounted for 93 percent of all reported cases in the US in 2005, with an overall incidence of 31.6 cases for every 100,000 persons.2
The incidence is highest among children 5 to 14 years of age, and more than 90 percent of cases report onset between April and November.2
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