Lyme Disease
Introduction.
Lyme disease is a relatively recently identified infection caused by
spirochaetes of the genus Borrelia. At least 3 species can cause Lyme disease in
humans. Transmission is by a tick bite. The natural reservoir for Lyme disease
includes rodents, deer, pets, and ticks.
Summary
- Cause: Borrelia burgdorferi & others
- Microscopy: Gram-negative spirals 3 - 30 um long
- Culture & Identification: Hard to culture; ELISA or
immunofluorescence
- Transmission: Ticks (zoonotic)
- Symptoms: Circular 'Bull's eye rash' may develop at site of tick
bite; malaise, fatigue, headache, fever, chills, myalgia (for ~ 4
weeks);
- Complications: If untreated, late stages may include encephalitis,
meningitis, cardiac dysfunction, arthritis starting 1 week - 2 years after
infection
- Pathogenesis: Thought to be immune system cross-reactivity to
Borrelia
- Treatment: Doxycycline or amoxicillin; vaccine available