LOCAL VARIATIONS IN THE DISTRIBUTION AND PREVALENCE OF BORRELIA-BURGDORFERI SENSU-LATO GENOMOSPECIES IN IXODES-RICINUS TICKS

Unfed nymphal and adult Ixodes ricinus ticks were collected from five locations within the 10,000-ha Killarney National Park, Ireland. The d istribution and prevalence of the genomospecies of Borrelia burgdorfer i sensu late in the ticks were investigated by PCR amplification of th e intergenic spacer region between the 5S and 23S rRNA genes and by re verse line blotting with genomospecies-specific oligonucleotide probes , The prevalence of ticks infected with B. burgdorferi sensu late was significantly variable between the five locations, ranging from 11.5 t o 28.9%. Four genomospecies were identified as B. burgdorferi sensu st ricto, Borrelia afzelii, Borrelia garinii, and VS116. Additionally, un typeable B. burgdoferi sensu lato genomospecies were identified in two nymphs, VS116 was the most prevalent of the genomospecies and was ide ntified in 50% of the infected ticks, Prevalences of B. garinii and B. burgdoferi sensu stricto were similar (17 and 18%, respectively); how ever, significant differences were observed in the prevalence of these genomospecies in mixed infections (58.8 and 23.5%, respectively). Not ably, the prevalence of B. afzelii was low, comprising 9.6 and 7.4%, r espectively, of single and mixed infections, Significant variability w as observed in the distribution and prevalence of B. burgdorferi sensu lato genomospecies between locations in the park, and the diversity a nd prevalence of B. burgdorferi sensu late genomospecies was typically associated with woodland. The distributions of B. burgdorferi sensu l ate genomospecies were similar in wooded areas and in areas bordering woodland, although the prevalence of B. burgdorferi sensu late infecti on was typically reduced. Spatial distributions vegetation composition , and host cenosis of the habitats were identified as factors which ma y affect the distribution and prevalence of B. burgdorferi sensu late genomospecies within the park.