Activity of the tick Ixodes ricinus monitored in a suburban park in Brno, Czech Republic, in association with the evaluation of selected repellents.

The ever-increasing number of Lyme borreliosis patients led us to consider more effective procedures for disease prevention. The aim of our study was to monitor the annual activity and infectivity of Ixodes ricinus ticks in the Pisárky region, City of Brno, CR, and to test the responses of the locally-captured ticks to selected repellents. The result of regular one-hour-per-week monitoring in 2011 was the collection of ticks that directly reflected the highest number of Lyme disease patients (4,835) detected throughout the period of recording in the Czech Republic. The ticks were examined for spirochaetes by dark field microscopy. The positive samples were identified by PCR analysis, confirming that 76% of these were infected with Borrelia burgdorferi sensu lato. Ticks were most abundant in May and June, with August having the highest risk for spirochaetal infection. Tick activity was statistically correlated with temperature. The moving-object-bioassay was used to study repellent efficiency on the Ixodes ricinus nymphs captured in the above-mentioned suburban park. Five selected commercial repellents based on DEET (N, N-diethyl-3-thylbenzamide) showed statistically different effects on the non-repellent control group.