[Lyme disease]

Lyme disease is an infectious disease due to Borrelia burgdorferi, which is transmitted by a tick bite. Bearing ticks belong to the "Ixodes" type. Germ reservoirs include rodents, birds, deers... The disease onset usually takes place in summer or in autumn. Its early stage is characterized by erythema chronicum migrans. The secondary stage, initiated by a virus-like syndrome indicating the hematogenous and lymphatic dissemination may include neurologic symptoms and signs--the most frequent ones in France and Europe (meningoradiculitis, meningitis, palsy of one or several cranial nerves), cardiac symptoms (conduction dysfunction), a relapsing oligoarthritis, and sometimes ocular signs. In some cases, joint and/or nervous system symptoms may become chronic: it's the tertiary (late) stage, which may include, too, acrodermatitis chronica atrophicans. Any of these symptoms may initiate the disease or be its only manifestation. When erythema chronicum migrans is missing, diagnosis lays upon serology which may turn positive only lately, or remain negative; the possibility of false positivity must also be noticed. Antibiotherapy must be initiated as soon as possible; even when started lately, it may prove beneficial. It consists essentially of beta lactamins or doxycyclin. Studies are progressing in view of the elaboration of a vaccine.