Tick-borne bacterial disease.
It was identified in 1975 and named for Old Lyme, Conn. It is caused by a spirochete , Borrelia burgdorferi , transmitted by tick s, which pick it up in the blood of infected animals, mostly deer. Humans can be bitten by ticks in tall grass or fallen leaves. Lyme disease has three stages: a target-shaped rash, often with flulike symptoms; migrating arthritic pain and neurological symptoms (disturbances to memory, vision, or locomotion); and crippling arthritis with symptoms like those of multiple sclerosis and sometimes with facial paralysis, meningitis, or memory loss. Most cases do not progress beyond the first stage, but those that do reach the third stage within two years. Prevention involves avoiding tick bites. Diagnosis can be difficult, especially if the initial rash is not noticed. Early antibiotic treatment can prevent progression. Advanced cases need more powerful antibiotics, and symptoms may recur.