Environmental conditioning of incidence of tick-borne encephalitis in the south-eastern Poland in 1996-2006.

Epidemiological studies of tick-borne encephalitis (TBE) conducted in the Swietokrzyskie province (south- eastern Poland) in 1996-2006 demonstrated an increase in the number of registered TBE cases in the last 6 years of the study. The highest risk of TBE virus infections occurs in the summer-autumn period (seasonality factors 96.55% and 248.28%), i.e. in periods of the highest Ixodes ricinus activity in this region. An increased number of registered TBE cases were noted in the regions which provide ticks with favourable habitats and, simultaneously, where the TBE diagnosis and treatment for the inhabitants are more efficient. The increasing tendency in TBE incidence observed even in the non-endemic regions of the Swietokrzyskie province indicates the necessity of education in tick-borne disease prophylaxis and the need to elevate the level of public health care. Differences in the density and activity of various developmental Ixodes ricinus stages were observed in 4 localities in diverse biotopes located at different altitudes a.s.l. This justifies the necessity of environmental monitoring of the threats posed by ticks in various habitats, especially in those frequently visited by humans.