Borrelia burgdorferi is an aetiological factor of borreliosis (
Lyme disease). The main vectors of Borrelia burgdorferi are larvae, nymphs, and females of Ixodes ricinus. The aim of this paper was to analyse infection parameters of Borrelia burgdorferi in a selected populations of Ixodes ricinus. The study was conducted in Tarnowskie Góry administrative district (Krupski M?yn, Zielona, Lubliniec, Tarnowskie Góry, Swierklaniec, Tworóg, and Zbros?awice). A total of 85 ticks were collected with a piece of cloth dragged over the vegetation. The Borrelia burgdorferi infection was confirmed with a PCR method, using flagellin protein gene DNA amplification. DNA of Borrelia burgderferi sensu lato was present in 14 ticks, which constituted 16.5% of the population studied. The percentage of infected females and nymphs was 26.8%, 22.2%, and 5.6%, respectively. A high prevalence of the pathogen (50%) was in ticks revealed in the recreation areas and the community forest in Swierklaniec.