Detection of three genospecies of Borrelia burgdorferi sensu lato in Ixodes ricinus ticks collected in different regions of Poland

Ixodes ricinus ticks, collected in 1996-1998 in different Polish woodlands, were examined to assess the frequency of the occurrence of Lyme borreliosi s-associated genospecies. A total of 568 samples of individual adults and 1 62 samples of individual in = 48) and pooled (of 2 to 7] samples of nymphs were analysed by the polymerase chain reaction (PCR) for Borrelia burgdorfe ri sensu late. Spirochetes were detected in 130 adult ticks (22.9 %) and in a minimum of 32 (5.3 %) nymphs. Further identification of 153 B. burgdorfe ri s, l.-positive samples by nested PCR using three species-specific primer s revealed the occurrence of B. afzelii, B. burgdorferi sensu stricto and B . garinii. Both single-species and mixed infections were noted. Single-spec ies infections were observed in the majority of samples (n = 83/153; 54.2 % ). Within this group B. afzelii was found in 38/153 samples (24.9 %), follo wed by B, burgdorferi sensu stricto in = 23/153; 15.0 %) and B. garinii (n = 22/153; 14.4 %). Dual infections with B. burgdorferi s. s. and B. afzelii were detected in 17/121 (14.0 %) adults, while both B. burgdorferi s. s. I B. garinii and B. afzelii/B. garinii coinfected 11/121 (9.1 %) adult ticks. Triple infection with B, burgdorferi s.s., B. afzelii and B. garinii was n oted twice (1.6 %). In general, B. afzelii was found in 72/153 (47.1 %) tic k samples and was the predominant species. B. burgdorferi s. s. and B. gari nii were detected in a total of 60/153 (39.2 %) and 51/153 (33.3 %) samples , respectively. Although, 21 (13.7 %) samples were infected by B. burgdorfe ri s.l. genospecies undetectable by the primers used, results of our study confirm that Lyme borreliosis pathogenic genospecies an well established in tick populations throughout Poland.