Lyme Disease - Emerging Infectious Disease

LYME DISEASE

Lyme disease, caused by the spirochete Borrelia burgdorferi, is transmitted to humans by ticks. It is more common in the North-east and Mid-Atlantic states, where the deer tick (Ixodes dammini) is prevalent. Ticks may feed on infected white-tailed deer or white-footed mice and then serve as a vector to transmit disease to humans. Lyme disease is less common in the western U.S. states, where the California black-legged tick (Ixodes pacificus), capable of transmitting Lyme disease, prefers to feed on reptiles, which do not carry B. burgdorferi.

Lyme disease can be manifested by a wide range of symptoms and severity. In its early form, a rash is often present and may be accompanied by regional lymphadenopathy. In later stages, neuro-logic manifestations ranging from Bell’s palsy to Guillain-Barré– like syndrome or dementia are possible. Other sites that may be affected include skin, joints, heart, and eyes.

Assessment and Diagnostic Findings

The rash frequently associated with Lyme disease, known as ery-thema migrans, is often described as having an expanding bull’s-eye appearance. It may be confused with a spider bite. The diagnosis may be made when a patient has this typical rash and at least one late manifestation (eg, arthritis, facial palsy, menin-gitis, carditis) along with laboratory confirmation of infection.

Medical Management

Doxycycline (Vibramycin), ceftriaxone (Rocephin), and azi-thromycin are among the commonly used antibiotics. Treatment regimens are usually for 3 to 4 weeks. Patients should be encour-aged to complete the full course of therapy and to report changes in symptoms during therapy, because the regimen may need to be altered if treatment appears to be failing.