title: Geodemographic analysis of Borrelia burgdorferi sensu lato using the 5S-23S rDNA spacer region.
abstract: BACKGROUND
  Lyme borreliosis is the predominant tick-borne disease in the Northern hemisphere, with considerable heterogeneity in clinical manifestations. Here, we evaluated one genetic marker for its use in population genetic based analysis. For that we collected molecular and epidemiological records of Borrelia burgdorferi sensu lato isolates from ticks, animals and humans at various sites in The Netherlands and worldwide.
  
  
  METHODS
  The 5S-23S rDNA (rrfA-rrlB) intergenic spacer region (IGS) from 291 Dutch Borrelia positive ticks was sequenced and compared to Borrelia sequences from GenBank. We estimated several population genetic measures to test the neutrality of the marker. We also assessed the ability of this marker to discriminate between Eurasian Borrelieae at a finer geographical resolution, and to detect population expansion per genospecies.
  
  
  RESULTS
  The most prevalent genospecies in The Netherlands was Borrelia afzelii, whereas Borrelia garinii, B. burgdorferi sensu stricto, Borrelia spielmanii and Borrelia valaisiana were found less frequently. The result of the Ewens-Watterson-Slatkin test was consistent with neutral selection of IGS region. Estimated pairwise fixation indices (Fst) were significantly different from zero between The Netherlands, the rest of Europe, Russia and Asia for B. afzelii and Borrelia garinii. Estimated Fu's Fs were significantly negative for B. afzelii and B. garinii.
  
  
  CONCLUSIONS
  At least seven B. burgdorferi s.l. genospecies circulate in Ixodes ricinus population in The Netherlands. The population genetic analyses of IGS region can resolve subpopulations within a genospecies and detect a large excess of rare genetic variants at the genospecies level. A genetic trace of population expansion for B. afzelii and B. garinii is consistent with the reported increase in Lyme borreliosis incidence in European countries.
authors.affiliation: Centre for Infectious Disease Control Netherlands, National Institute for Public Health and Environment, RIVM, PO Box 1, 3720 BA Bilthoven, The Netherlands. Claudia.Coipan@rivm.nl
authors.forename: Elena Claudia
authors.initials: EC
authors.lastname: Coipan
authors.forename: Manoj
authors.initials: M
authors.lastname: Fonville
authors.forename: Ellen
authors.initials: E
authors.lastname: Tijsse-Klasen
authors.forename: Joke W B
authors.initials: JW
authors.lastname: van der Giessen
authors.forename: Willem
authors.initials: W
authors.lastname: Takken
authors.forename: Hein
authors.initials: H
authors.lastname: Sprong
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Takumi
mesh_terms: D001208:Asia; D025065:Borrelia burgdorferi / Q000145:classification* / Q000235:genetics*; D016000:Cluster Analysis; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D005060:Europe; D019143:Evolution, Molecular; D014644:Genetic Variation; D006239:Haplotypes; D058885:Multilocus Sequence Typing; D009426:Netherlands; D010802:Phylogeny; D012338:RNA, Ribosomal, 23S / Q000235:genetics*; D012341:RNA, Ribosomal, 5S / Q000235:genetics*
chemical_list: D021903:DNA, Ribosomal Spacer; D012338:RNA, Ribosomal, 23S; D012341:RNA, Ribosomal, 5S