[Ticks Ixodes ricinus (Linnaeus, 1758) from selected municipal forests of the city Poznań and their infection with the spirochetes Borrelia burgdorferi senso lato].
The results of research (1997-1998) on the occurrence of the spirochetes Borrelia burgdorferi s.l. in ticks Ixodes ricinus (L.) in selected municipal forests of the city of Poznań (localities--districts of Poznań: 1 Debiec, 2 Marcelin, 3 Golecin and Wola, 4 Krzyzowniki and Smochowice, 5 Kiekrz and Strzeszynek, 6 Morasko, 7 Piatkowo, 8 Umultowo, 9 Naramowice and Rózany Młyn, 10 Malta and Antoninek) are presented. A total of 1432 ticks were collected from 10 localities (748 larvae, 590 nymphs, 47 males, and 47 females). Out of this number, 266 specimens were selected at random for further analysis (20 larvae, 160 nymphs, 44 males, and 42 females) which were then tested for the presence of the spirochetes using the PCR technique (tab. I-III, fig. 1). Spirochetes were found in 60 specimens (22.6%). Percentages of infected nymphs and males were similar: 25.6% and 27.3%, respectively. The level of infection of females was lower (14.3%) and of larvae lowest (5.0%). Infected ticks were found in all ten localities, but their proportions differed from site to site and varied from 9.5% (Piatkowo) to 34.6% (Krzyzowniki and Smochowice). Special attention was devoted to those municipal woods where ticks were abundant (Kiekrz and Strzeszynek, as well as Malta and Antoninek, and relatively numerous Debiec) and where their extensiveness of infestation was high (Krzyzowniki and Smochowice: 34.6%; Debiec: 29.6%; Naramowice and Rózany Młyn: 28.6%; Malta and Antoninek: 28.1%; and Golecin and Wola: 26.9%). After summing up all the data from the literature on Wielkopolska and the city of Poznań, the mean extensiveness of infestation in Wielkopolska turns out to be 21.8% and in Poznań slightly higher, 22.2% (tab. IV). The infection levels of the particular developmental stages are different, though: highly variable in nymphs (8.3-25.6%), and more stable in males (22.0-27.3%) and females (22.0-24.5%).