[Lyme disease: biological diagnosis and treatment]

In daily practice the diagnosis of Lyme disease is confirmed in the laboratory by serological tests the specificity and sensitivity of which are not fully satisfactory. There are false-positive results due to antibodies directed against antigens others than Borrelia burgdorferi, but the main problem is that most people living in endemic areas have specific antibodies while being, and remaining, asymptomatic. In addition, the sensitivity of the current tests is mediocre at the onset of the disease. A negative serology therefore should not exclude definitively a diagnosis of Lyme disease, just as a positive serology should not compulsorily lead to this diagnosis in patients with atypical clinical signs. The treatment of Lyme disease aims at eradicating the organisms, including those wHich infest the central nervous system. Beta-lactam antibiotics seem to be particularly suitable for this purpose: amoxycillin is used in ambulatory patients, and ceftriaxone is probably the most effective treatment of severe neurological manifestations of the disease.