In several European countries, tick-borne encephalitis (TBE) is one of the most important human infections of the central nervous system. The disease agent, i.e. the TBE virus (TBEV), is transmitted via tick bites. The virus persists in so-called natural foci, where it circulates among vertebrate hosts (mainly rodents) and the arthropod host (tick).The disease occurs in Western and Central Europe, Scandinavia, countries that made up the former Soviet Union, and Asia, corresponding to the distribution of the ixodid tick reservoir. Most natural foci are well described, but new TBE areas could emerge or re-emerge. At least 10,000 cases of TBE are referred to hospitals each year. TBE has also become an international public health problem because of the increasing mobility of people traveling to risk areas. Today the risk of infection is especially high for all people who pursue leisure activities in nature in endemic areas.
TBE virus is rarely found in Bulgaria, Greece, Italy, Norway, Romania and Japan. Only sporadic cases have been reported so far. In several European countries no TBE cases have been found as yet; among these are Great Britain, Ireland, Iceland, Belgium, the Netherlands, Luxemburg, Spain, and Portugal.
Lyme borreliosis is another tick-borne disease of similar epidemiological dimensions in Central Europe. It is caused by spirochetes and can be managed with administration of antibiotics, whereas no effective therapy exists against TBE.
The clinical picture of TBE was first described in Austria in 1931 by H. Schneider. Shortly afterwards, it was observed in the Far-East of the former USSR, and from 1939 onwards also in its European part. In 1948, the virus was isolated for the first time outside the former USSR. In subsequent years, TBE was identified in other European countries. Synonyms for TBE are spring-summer meningoencephalitis, Central European encephalitis, Far-East Russian encephalitis, Taiga encephalitis, or Russian spring-summer encephalitis, biundulating meningoencephalitis, diphasic milk fever, Kumlinge disease, Schneider’s disease. The name ”tick-borne encephalitis” refers to the tick, its main vector.