Long-term population dynamics of ixodid ticks and development of tick-borne encephalitis foci under conditions of the middle taiga subzone

Long-term (1995-2003) population dynamics of ixodid ticks and their main hosts (small mammals) and conditions providing for the formation of tick-borne encephalitis (TBE) foci were studies in the middle taiga subzone (Karelia). The results show that the bank vole (Clethrionomys glareolus Sclir.) is the main host for the larvae and nymphs of Ixodes persulcatus Schulze, 1930 and for, the larvae, nymphs, and adult individuals of I. trianguliceps Birula, 1895. The proportion of ticks feeding on this species (relative to their total number) reaches 63.3% (64.0% of L persulcatus and 61.1 % of I. trianguliceps). Activity of a TBE focus is determined primarily by the abundance of bank voles of older age groups.