title: Novel spotted fever group rickettsiae in Haemaphysalis qinghaiensis ticks from Gansu, Northwest China.
abstract: BACKGROUND
  Rickettsia spp. are obligate intracellular bacteria and well known as transmitted by arthropods. These pathogens have a broad geographic distribution and a high degree of biological and clinical diversity. This study was conducted to determine the prevalence and molecular characterization of Rickettsia spp. in ticks collected from Gansu, where Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum were previously reported in ticks and ruminants.
  
  
  METHODS
  A total of 1,583 questing Haemaphysalis qinghaiensis ticks were collected and tested for the presence of Rickettsia spp. gltA gene by PCR. Samples positive for gltA were examined by specific primers targeted for the ompA gene of SFG rickettsiae. The infections were further validated by sequencing and positive samples were genetically characterized based on the gltA and ompA genes.
  
  
  RESULTS
  In total, Rickettsia spp. infection was found in 179 (18.5 %) H. qinghaiensis tick pools by using PCR and primers specific for the gltA gene. Of those, 157 (16.3 %) tick pools were positive for SFG rickettsiae by PCR based on ompA gene. Amplification and molecular analysis of the nucleotide sequences of gltA and ompA genes indicated three potential novel spotted fever group rickettsiae in H. qinghaiensis ticks. These three potential novel spotted fever group rickettsiae were clustered together in a subgroup, which represents a sister taxon to and separates from other known four SFG rickettsiae subgroups.
  
  
  CONCLUSIONS
  This study revealed a high infection rate of SFG rickettsiae in H. qinghaiensis ticks in northwest China. Three potential novel spotted fever group rickettsiae classified into a novel SFG rickettsiae subgroup were identified and named "Candidatus Rickettsia gannanii" related strains in recognition of the location where it was first detected.
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu, 730046, P. R. China.
authors.forename: Jifei
authors.initials: J
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu, 730046, P. R. China.
authors.forename: Zhancheng
authors.initials: Z
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu, 730046, P. R. China.
authors.forename: Zhijie
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu, 730046, P. R. China.
authors.forename: Qingli
authors.initials: Q
authors.lastname: Niu
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu, 730046, P. R. China.
authors.forename: Rong
authors.initials: R
authors.lastname: Han
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu, 730046, P. R. China.
authors.forename: Youquan
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu, 730046, P. R. China.
authors.forename: Guiquan
authors.initials: G
authors.lastname: Guan
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu, 730046, P. R. China.
authors.forename: Junlong
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu, 730046, P. R. China.
authors.forename: Guangyuan
authors.initials: G
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu, 730046, P. R. China. luojianxun@caas.cn.
authors.forename: Jianxun
authors.initials: J
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, Gansu, 730046, P. R. China. yinhong@caas.cn.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, P. R. China. yinhong@caas.cn.
authors.forename: Hong
authors.initials: H
authors.lastname: Yin
mesh_terms: D000818:Animals; D002681:China; D016000:Cluster Analysis; D004269:DNA, Bacterial; D005798:Genes, Bacterial; D026863:Ixodidae / Q000382:microbiology*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012281:Rickettsia / Q000145:classification* / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
chemical_list: D004269:DNA, Bacterial
keywords: Rickettsia sp; SFG rickettsia; Tick; gltA gene; ompA gene