Influence of climatic factors on dynamics of questing Ixodes ricinus ticks in Slovenia.

Ixodes ricinus is a vector of pathogens that cause many diseases in Europe and Slovenia: tick-borne encephalitis (TBE), anaplasmosis, borreliosis, babesiosis and others. The risk for contracting these diseases depends strongly on the density of the infected questing ticks and many studies have investigated tick population dynamics and the parameters affecting them. They have shown a clear influence of climatic and landscape arrangements in the microhabitat on tick abundance and dynamics and therefore on transmission of pathogens important in human and veterinary medicine. In our study we assessed the influence of climatic factors on questing activity of ticks over a three-year period at 7 locations in Slovenia. Locations were selected in endemic foci of TBE with different intensity, which were identified according to the presence of human disease. Sites differ according to various abiotic and biotic factors, such as climate, amount of rain, height above sea level, vegetation and wildlife. All three stages of ticks were collected monthly over a three-year period (2005-2007). Temperature, humidity and precipitation data were collected for these years. The purpose of our study was to relate observed differences in I. ricinus ticks questing activity to local climate. We found a correlation between the decrease of questing ticks in the summer and the combination of air temperatures and humidity in the form of saturation deficit.