title: Human infection with a novel tick-borne Anaplasma species in China: a surveillance study.
abstract: BACKGROUND
  Anaplasma phagocytophilum and Anaplasma ovis cause human infections. We investigated the potential for human pathogenicity of a newly discovered Anaplasma species infecting goats in China.
  
  
  METHODS
  We collected blood samples from patients with a history of tick bite in the preceding 2 months at Mudanjiang Forestry Central Hospital of Heilongjiang Province from May 1, to June 10, 2014, to detect the novel Anaplasma species by PCR. We inoculated positive samples into cell cultures. We characterised the isolated pathogen by morphological and phylogenetic analyses. We tested serum antibodies by indirect immunofluorescence assay.
  
  
  RESULTS
  28 (6%) of 477 patients assessed were infected with the novel Anaplasma species according to PCR and sequencing. We isolated the pathogen in vitro from three patients. Phylogenetic analyses of rrs, gltA, groEL, msp2, and msp4 showed that the pathogen was distinct from all known Anaplasma species. We provisionally nominate it "Anaplasma capra". 22 (92%) of 24 patients with data available had seroconversion or a four-fold increase in antibody titres. All 28 patients developed non-specific febrile manifestations, including fever in 23 (82%), headache in 14 (50%), malaise in 13 (46%), dizziness in nine (32%), myalgia in four (14%), and chills in four (14%). Additionally, ten (36%) of 28 patients had rash or eschar, eight (29%) had lymphadenopathy, eight (29%) had gastrointestinal symptoms, and three (11%) had stiff neck. Five patients were admitted to hospital because of severe disease. Six (35%) of 17 patients with data available had high hepatic aminotransferase concentrations.
  
  
  CONCLUSIONS
  The emergence of "A capra" as a cause of human disease suggests that individuals living in or travelling to endemic regions in northern China should take precautions to reduce their risk of exposure to this novel tick-borne pathogen.
  
  
  BACKGROUND
  Natural Science Foundation of China and the US National Institutes of Health.
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.affiliation: Mudanjiang Forestry Central Hospital, Mudanjiang, Heilongjiang Province, China.
authors.forename: Yuan-Chun
authors.initials: YC
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Na
authors.initials: N
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Bao-Gui
authors.initials: BG
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Rui-Ruo
authors.initials: RR
authors.lastname: Jiang
authors.affiliation: Mudanjiang Forestry Central Hospital, Mudanjiang, Heilongjiang Province, China.
authors.forename: Qiu-Bo
authors.initials: QB
authors.lastname: Huo
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Ya-Wei
authors.initials: YW
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Hong-Bo
authors.initials: HB
authors.lastname: Liu
authors.affiliation: Mudanjiang Forestry Central Hospital, Mudanjiang, Heilongjiang Province, China.
authors.forename: Yan-Li
authors.initials: YL
authors.lastname: Chu
authors.affiliation: Mudanjiang Forestry Central Hospital, Mudanjiang, Heilongjiang Province, China.
authors.forename: Yu-Dong
authors.initials: YD
authors.lastname: Song
authors.affiliation: Mudanjiang Forestry Central Hospital, Mudanjiang, Heilongjiang Province, China.
authors.forename: Nan-Nan
authors.initials: NN
authors.lastname: Yao
authors.affiliation: Mudanjiang Forestry Central Hospital, Mudanjiang, Heilongjiang Province, China.
authors.forename: Tie
authors.initials: T
authors.lastname: Sun
authors.affiliation: Shanghai Institute of Medical Genetics, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Fan-Yi
authors.initials: FY
authors.lastname: Zeng
authors.affiliation: Departments of Pathology and Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: J Stephen
authors.initials: JS
authors.lastname: Dumler
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Jia-Fu
authors.initials: JF
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China. Electronic address: caowc@bmi.ac.cn.
authors.forename: Wu-Chun
authors.initials: WC
authors.lastname: Cao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000709:Anaplasma / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D000818:Animals; D018929:Cell Culture Techniques; D002648:Child; D002681:China / Q000453:epidemiology; D016873:Ehrlichiosis / Q000453:epidemiology*; D062665:Epidemiological Monitoring; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017282:Tick-Borne Diseases / Q000453:epidemiology*; D055815:Young Adult