Incidence of spirochetes (Borrelia sp.) in the tick Ixodes ricinus in the urban environment (capital of Prague) between 1994-1997.

A total of 12287 ticks were collected from 10 localities of the capital of Prague between 1994 and 1997 (2978 ticks in 1994, 5612 ticks in 1995-1996, 3686 ticks in 1997). The presence of Borrelia was investigated by the indirect immunofluorescence assay using hyperimmune rabbit sera. The tick infestation ranged between 3.8% and 9.7% (1994), 7.9% and 11.3% (1995), 3.6% and 6.2% (1996) and 4.8% and 9.2% (1997). The results obtained are indicative of a relatively high opportunity for exposure to the causative agent in Prague--the dynamics of the spirochete positivity rates in ticks in different years corresponds with the dynamics recorded in the incidence of Lyme borreliosis in the same region.