[Tick-borne encephalitis].

Tick-borne encephalitis (TBE) is one of the most important viral infections of the human central nervous system. Approximately 10,000 cases of TBE are referred to hospitals in Europe and Asia each year. The TBE virus (TBEV) is mainly transmitted by tick bites but also occasionally by unpasteurized goat's milk. As in endemic areas on average only 1-3 % of ticks are infected with the TBEV and the clinical manifestation rate is approximately 33 %, only approximately 1 in every 100-300 tick bites leads to disease. The incubation period varies from 5-28 days and typically has a biphasic course of fever. The TBE manifests as meningitis in approximately 50 % of patients, as meningoencephalitis in 40 % and as encephalomyelitis in 10 %. The suspected diagnosis is confirmed by the demonstration of TBEV-specific IgM and IgG antibodies in serum and the presence of elevated cell counts in cerebrospinal fluid. No specific treatment for TBE is known but it can be successfully prevented by active immunization.