Sixty Years of Research of Tick-borne Encephalitis - a Basis of the Current Knowledge of the Epidemiological Situation in Central Europe
Abstract
Tick-borne encephalitis (TBE) virus was isolated for the first time in Central Europe in 1948 from both a patient and Ixodes ricinus ticks collected in the area where the patient had been tick bitten (the Beroun area - Central Bohemia) and concomitantly from a TBE patient in Moravia (the Vyškov area). Another priority discovery was alimentary transmission of TBE virus via the milk from tick infected grazing goats that was made during a TBE outbreak in Rožňava (SE Slovakia).
This outbreak of 660 cases has been the largest of its kind. Both of these discoveries were a challenge to multidisciplinary research into the natural focality of TBE.
The results obtained were published by Czech and Slovak authors in the first European TBE monograph (1954) and were the stimulus for further research in this area. From the epidemiological point of view, among others, the impact of meteorological factors (on TBE incidence associated with I. ricinus host-seeking activity) and recreational nature of TBE were clearly defined then.
At the same time, TBE became a notifiable disease (since 1971 laboratory confirmed TBE cases only). In the following decades, the phenomenon of natural focality of TBE (including anthropic impacts) was extensively studied and the determinants of high-risk areas in the field were analyzed.
The results were used in the creation of I. ricinus and TBE risk prediction maps for the Czech Republic generated for the first time in Europe using LANDSAT 5 satellite data and GIS technology (1990). In the early 1990s (in particular since 1993), similarly to other countries, the Czech Republic reported a sharp rise in TBE cases that continues, with some fluctuations, until now.
The cooperation with climatologists in the analysis of historical data, current epidemiological observations, and study of I. ricinus in the field have shown a decisive impact of the ongoing climate change.