[Occurrence of genomic species of Borrelia burgdorferi sensu lato in populations of Ixodes ricinus ticks from West Pomerania].

The aim of this study was to determine the incidence of Borrelia burgdorferi sensu lato infections in Ixodes ricinus ticks from recreational areas of the province of West Pomerania. Ticks (nymphs and adults) were collected between April and October 2000 and 2001 from 10 sampling sites. The presence of the spirochete, Borrelia burgdorferi sensu lato, was confirmed with an indirect fluorescence assay (IFA) and the polymerase chain reaction (PCR). In addition, a nested PCR technique was used to detect one of three genomic species of the bacteria (B. burgdorferi sensu stricto, B. garinii, B. afzelii). A total of 2380 ticks were studied, including 2195 nymphs, 89 females and 96 males. Peak collection was in June of 2000 (330 ticks) and in August of 2001 (156 ticks) (Table 4). Collection was lowest in October of 2000 (93 ticks) and 2001 (127 ticks) (Tables 2 and 4). The mean infection frequency of Ixodes ricinus as determined with PCR was 12.8% in 2000 and 10.9% in 2001. The frequency determined with IFA was 11.6% (2000) and 9.6% (2001) (Tables 1 and 3, Figs. 1 and 2). The nested PCR technique revealed that the dominant genospecies was B. burgdorferi sensu stricto (83.5% of ticks in 2000 and 87.7% in 2001), followed by B. garinii (12% and 10.2% in 2000 and 2001, respectively). B. afzelii was detected in 4.4% (2000) and 2% (2001) of ticks. Co-infection with B. burgdorferi sensu stricto and B. garinii occurred in 3.4% (2000) and 1.8% of ticks (2001). Determination of the genomic species was not possible in approximately 7% of ticks (Tables 5 and 6). The present results show that there is a substantial risk of contacting borreliosis in recreational areas in the vicinity of Szczecin.