In 1996-1998, a total of 2285 Ixodes ricinus ticks (1063 nymphs, 637 males,
585 females) were collected from vegetation from 25 different localities in the 8 Polish
provinces throughout the country. Ticks inhabited all 25 collection sites. The average
number of ticks per collection site was 91.4 ± 13.7. All 2285 ticks were examined for
Borrelia burgdorferi sensu lato (s.l.) presence, of which 1333 specimens from 3
provinces were tested by routine indirect immunofluorescence assay (IFA) using
polyclonal antibody PAB 1B29. The remaining 952 specimens from 5 provinces were
examined by polymerase chain reaction (PCR), using FL6 and FL7 primers. The overall
infection rate in ticks estimated by these 2 methods was 10.2%. Nymphs showed lower
positivity rate (6.2%) as compared to adult ticks (14.9% in females and 12.4% in
males). The highest percentage of infected I. ricinus ticks (37.5%) was noted in the
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collection sites, infection rates varied from 0–37.5%. The obtained results confirmed
that B. burgdorferi s.l. is present throughout the distributional areas of I. ricinus in
Poland and that a prevalence of spirochete-infected ticks may be high in some locations