title: Typing African relapsing fever spirochetes.
abstract: Relapsing fever Borrelia spp. challenge microbiologic typing because they possess segmented genomes that maintain essential genes on large linear plasmids. Antigenic variation further complicates typing. Intergenic spacer (IGS, between 16S-23S genes) heterogeneity provides resolution among Lyme disease-associated and some relapsing fever spirochetes. We used an IGS fragment for typing East African relapsing fever Borrelia spp. Borrelia recurrentis and their louse vectors showed 2 sequence types, while 4 B. duttonii and their tick vectors had 4 types. IGS typing was unable to discriminate between the tick- and louseborne forms of disease. B. crocidurae, also present in Africa, was clearly resolved from the B. recurrentis/B. duttonii complex. IGS analysis of ticks showed relapsing fever Borrelia spp. and a unique clade, distant from those associated with relapsing fever, possibly equivalent to a novel species in ticks from this region. Clinical significance of this spirochete is undetermined.
authors.affiliation: Department of Cellular and Molecular Biology, Imperial College of Science, Technology and Medicine, South Kensington, London, United Kingdom.
authors.forename: Julie Christine
authors.initials: JC
authors.lastname: Scott
mesh_terms: D000818:Animals; D001179:Arthropod Vectors / Q000382:microbiology*; D015373:Bacterial Typing Techniques; D001769:Blood / Q000382:microbiology; D001898:Borrelia / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000032:analysis; D021903:DNA, Ribosomal Spacer / Q000032:analysis; D005002:Ethiopia; D006801:Humans; D007303:Insect Vectors / Q000382:microbiology*; D008969:Molecular Sequence Data; D008003:Phthiraptera / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D012061:Relapsing Fever / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D013636:Tanzania; D017282:Tick-Borne Diseases / Q000382:microbiology; D013987:Ticks / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S