[Relation of foci of tick-borne encephalitis to original plant associations in the Czech Republic].

Based on reports of the hygiene service on the morbidity from tick-borne encephalitis during the period of 1953-1987, data in the literature and results of the authors' field research on the incidence of ticks, the authors defined foci of the disease. In Bohemia there is an extensive important focus of tick-borne encephalitis in the Central Bohemian region in the Krivoklát area, along the Berounka river, along the mid Vltava river and lower Sázava river, in the area of the Brdy mountains and Czech Karst, linked in the South along the Vltava river to foci in the South Bohemian region in the districts of Písek and Ceské Budĕjovice and in the West linked along the Berounka river with the focus in the central part of the West Bohemian region. In the North Bohemian region and East Bohemian region, only minor separate relict foci of tick-borne encephalitis were found. In Moravia there are extensive foci of tick-borne encephalitis in the North Moravian region in the districts of Opava and Bruntál, in the South Moravian region in its central and southern parts. The foci in Bohemia are separated from foci in neighbouring countries, foci in Moravia are continuous with those in Poland and Austria. It was proved that ticks and the revealed foci of tick-borne encephalitis in the Czech Republic are in areas of original oak groves. Areas of beech woods, even those which are below areas where ticks are found, i.e. lower that 700 m above sea level, do not offer favourable conditions for ticks andare not foci of tick-borne encephalitis. Assessment of areas with regard to the prevailing flora and fauna proved a useful method of prediction of the occurrence of ticks and foci of disease they transmit.