Lyme Disease: A Comprehensive Overview

Introduction
Lyme disease is a multisystem infectious disease caused primarily by the bacterium Borrelia burgdorferi, transmitted to humans through the bite of infected black-legged ticks (commonly known as deer ticks). First recognized in Lyme, Connecticut, in the 1970s, it is now the most common vector-borne illness in North America and parts of Europe.

Etiology and Transmission

The causative agents are spirochete bacteria, primarily Borrelia burgdorferi in the United States and Borrelia afzelii or Borrelia garinii in Europe and Asia. Transmission occurs through the bite of Ixodes species ticks, which acquire the bacteria by feeding on infected animals such as rodents or deer.

Ticks must typically be attached for 36 to 48 hours to transmit the bacteria.

Epidemiology

Lyme disease is endemic in:

  • Northeastern and upper Midwestern United States
  • Central Europe
  • Some parts of Asia

It is more common in spring and summer months when ticks are most active.

Clinical Manifestations

Lyme disease progresses through three stages:

1. Early Localized Stage (Days to Weeks After Bite)

  • Erythema migrans (EM): A hallmark bull’s-eye rash at the bite site, appearing in ~70–80% of cases
  • Fever, fatigue, headache, muscle aches
  • Local lymphadenopathy

2. Early Disseminated Stage (Weeks to Months)

  • Multiple EM lesions
  • Migratory joint pain (especially knees)
  • Neurologic symptoms:
    • Facial nerve palsy (Bell’s palsy)
    • Meningitis
    • Radiculoneuritis
  • Cardiac involvement:
    • Lyme carditis with atrioventricular block

3. Late Disseminated Stage (Months to Years)

  • Lyme arthritis, especially affecting large joints
  • Chronic neurologic complications:
    • Encephalopathy
    • Cognitive disturbances
    • Peripheral neuropathy

Diagnosis

Diagnosis is clinical, supported by laboratory testing when appropriate.

Laboratory Tests:

  • Two-tiered serologic testing:
    1. Enzyme-linked immunosorbent assay (ELISA)
    2. Confirmatory Western blot
  • PCR testing for Borrelia DNA in synovial fluid or cerebrospinal fluid (less common)
  • ECG and lumbar puncture in selected cases (cardiac or neurologic involvement)

Treatment

Early Lyme Disease:

  • Doxycycline 100 mg twice daily for 10–21 days
    • Alternative: Amoxicillin or cefuroxime for children or pregnant women

Neurologic or Cardiac Involvement:

  • IV ceftriaxone or penicillin G for 14–28 days

Late Lyme Arthritis:

  • Oral doxycycline or amoxicillin for 28 days
  • Persistent cases may need IV antibiotics

Complications

  • Chronic joint inflammation
  • Persistent neurologic symptoms
  • Post-treatment Lyme disease syndrome (PTLDS): fatigue, pain, and cognitive symptoms lasting months despite appropriate antibiotic therapy

Prevention

  • Avoid tick-infested areas, especially during peak seasons
  • Use insect repellents (e.g., DEET or permethrin)
  • Wear long sleeves and pants
  • Perform tick checks after outdoor activities
  • Prompt removal of attached ticks (with tweezers, gripping close to the skin)

Vaccine Status

Currently, there is no approved human vaccine in the U.S., but candidates are under development.

Conclusion

Lyme disease is a significant public health concern in endemic areas, but it is preventable and treatable when diagnosed early. Awareness of symptoms, early medical consultation, and preventive measures are essential to minimize complications and chronic illness.

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