title: Orientia tsutsugamushi, agent of scrub typhus, displays a single metapopulation with maintenance of ancestral haplotypes throughout continental South East Asia.
abstract: Orientia tsutsugamushi is the causative agent of scrub typhus, a major cause of febrile illness in rural area of Asia-Pacific region. A multi-locus sequence typing (MLST) analysis was performed on strains isolated from human patients from 3 countries in Southeast Asia: Cambodia, Vietnam and Thailand. The phylogeny of the 56-kDa protein encoding gene was analyzed on the same strains and showed a structured topology with genetically distinct clusters. MLST analysis did not lead to the same conclusion. DNA polymorphism and phylogeny of individual gene loci indicated a significant level of recombination and genetic diversity whereas the ST distribution indicated the presence of isolated patches. No correlation was found with the geographic origin. This work suggests that weak divergence in core genome and ancestral haplotypes are maintained by permanent recombination in mites while the 56-kDa protein gene is diverging in higher speed due to selection by the mammalian immune system.
authors.affiliation: Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; UM2, ISEM, UMR 5554, CNRS-UM2-IRD, Université Montpellier 2 CC065, Place E. Bataillon, 34095 Montpellier Cedex 5, France.
authors.forename: Patimaporn
authors.initials: P
authors.lastname: Wongprompitak
authors.affiliation: Virology Unit, Institut Pasteur in Cambodia, 5 Monivong blvd, PO Box 983, Phnom Penh, Cambodia.
authors.forename: Veasna
authors.initials: V
authors.lastname: Duong
authors.affiliation: Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; Graduate Program in Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
authors.forename: Wichittra
authors.initials: W
authors.lastname: Anukool
authors.affiliation: Virology Unit, Institut Pasteur in Cambodia, 5 Monivong blvd, PO Box 983, Phnom Penh, Cambodia.
authors.forename: Lay
authors.initials: L
authors.lastname: Sreyrath
authors.affiliation: Institut Pasteur of Nha Trang, 10 Tran Phu Street, Nha Trang, Viet Nam.
authors.forename: Trinh Thi Xuan
authors.initials: TT
authors.lastname: Mai
authors.affiliation: UM2, ISEM, UMR 5554, CNRS-UM2-IRD, Université Montpellier 2 CC065, Place E. Bataillon, 34095 Montpellier Cedex 5, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Gavotte
authors.affiliation: UM2, ISEM, UMR 5554, CNRS-UM2-IRD, Université Montpellier 2 CC065, Place E. Bataillon, 34095 Montpellier Cedex 5, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Moulia
authors.affiliation: UM1, CPBS, UMR 5236, CNRS-UM1-UM2, 1919 route de Mende, 34293 Montpellier Cedex 5, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Cornillot
authors.affiliation: Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
authors.forename: Pattama
authors.initials: P
authors.lastname: Ekpo
authors.affiliation: Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
authors.forename: Yupin
authors.initials: Y
authors.lastname: Suputtamongkol
authors.affiliation: Virology Unit, Institut Pasteur in Cambodia, 5 Monivong blvd, PO Box 983, Phnom Penh, Cambodia.
authors.forename: Philippe
authors.initials: P
authors.lastname: Buchy
authors.affiliation: UM2, CPBS, UMR 5236, CNRS-UM1-UM2, 1919 route de Mende, 34293 Montpellier Cedex 5, France; Cirad, UMR 17, Cirad-Ird, TA-A17/G, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France. Electronic address: roger.frutos@univ-montp2.fr.
authors.forename: Roger
authors.initials: R
authors.lastname: Frutos
mesh_terms: D001210:Asia, Southeastern / Q000453:epidemiology; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D006239:Haplotypes; D006801:Humans; D058885:Multilocus Sequence Typing; D012285:Orientia tsutsugamushi / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012612:Scrub Typhus / Q000453:epidemiology* / Q000382:microbiology*; D012641:Selection, Genetic
keywords: 56-kDa protein; Genetic diversity; MLST; Orientia tsutsugamushi; Polymorphism; Scrub typhus