title: Novel clade of Rickettsia spp. from leeches.
abstract: Intracellular rickettsia-like structures were found in the tissues of a glossiphoniid leech, Torix tagoi, by transmission electron microscopy. Diagnostic PCR analysis using specific primers suggested that of the nine glossiphoniid species examined, two species, T. tagoi and Hemicrepsis marginata, harbored bacteria of the genus Rickettsia. A 1.5-kb eubacterial 16S rRNA gene segment obtained from each of these species was amplified by PCR, cloned, and sequenced. Phylogenetic analysis of the 16S rRNA gene demonstrated that the Rickettsia species found in the leeches constituted a novel clade that is distinct from the clade of arthropod-associated Rickettsia species. In natural populations, 97.7% (43 of 44) of T. tagoi leeches and 100% (9 of 9) of H. marginata leeches carried Rickettsia, suggesting that infection with Rickettsia is prevalent in these leeches. This is the first report of Rickettsia found in annelids.
authors.affiliation: Natural History Laboratory, Faculty of Science, Ibaraki University, Mito 310-8512, Japan.
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: Shinya
authors.initials: S
authors.lastname: Sameshima
authors.forename: Osamu
authors.initials: O
authors.lastname: Kitade
authors.forename: Junichi
authors.initials: J
authors.lastname: Kojima
authors.forename: Takema
authors.initials: T
authors.lastname: Fukatsu
mesh_terms: D000818:Animals; D020459:Genes, rRNA; D007865:Leeches / Q000382:microbiology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012281:Rickettsia / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000648:ultrastructure; D017422:Sequence Analysis, DNA
chemical_list: D012336:RNA, Ribosomal, 16S