Lyme disease

Lyme disease.Erythema chronicum migrans. Expanding “bull’s eye” red rash.

Caused by Borrelia burgdorferi,which is transmitted by the tick Ixodes A (also vector for Babesia). Natural reservoir is the mouse.Mice are important to tick life cycle.

Common in northeastern United States.

Initial symptoms—erythema chronicum migrans, flu-like symptoms, +/- facial nerve palsy.
Later symptoms—monoarthritis (large joints) and migratory polyarthritis, cardiac (AV nodal block), neurologic (encephalopathy, facial nerve palsy, polyneuropathy).

Treatment: doxycycline, ceftriaxone.