title: Infections with the tick-borne bacterium "Candidatus Neoehrlichia mikurensis" mimic noninfectious conditions in patients with B cell malignancies or autoimmune diseases.
abstract: BACKGROUND
  Candidatus Neoehrlichia mikurensis is a newly discovered noncultivatable bacterium spread among ticks and rodents in Europe and Asia that can infect humans, particularly immunocompromised patients.
  
  
  METHODS
  We compiled clinical and laboratory data from 11 patients with hematological malignances or autoimmune diseases who were diagnosed with Candidatus N. mikurensis infection in Europe 2010-2013. Both published (6) and unpublished cases (5) were included.
  
  
  RESULTS
  The patients had a median age of 67, were mostly male (8/11), and resided in Sweden, Switzerland, Germany, and the Czech Republic. All but one had ongoing or recent immune suppressive treatment and a majority were splenectomized (8/11). Less than half of them recalled tick exposure. The most frequent symptoms were fever (11/11), localized pain afflicting muscles and/or joints (8/11), vascular and thromboembolic events (6/11), that is, deep vein thrombosis (4), transitory ischemic attacks (2), pulmonary embolism (1), and arterial aneurysm (1). Typical laboratory findings were elevated C-reactive protein, leukocytosis with neutrophilia, and anemia. Median time from onset of symptoms to correct diagnosis was 2 months. In at least 4 cases, the condition was interpreted to be due to the underlying disease, and immunosuppressive therapy was scheduled. All patients recovered completely when doxycycline was administered.
  
  
  CONCLUSIONS
  Candidatus N. mikurensis is an emerging tick-borne pathogen that may give rise to a systemic inflammatory syndrome in persons with hematologic or autoimmune diseases that could be mistaken for recurrence of the underlying disease and/or unrelated arteriosclerotic vascular events. Awareness of this new pathogen is warranted among rheumatologists, hematologists, oncologists, and infectious disease specialists.
authors.affiliation: Department of Clinical Microbiology/Infectious Diseases, Sahlgrenska Academy, Sahlgrenska University Hospital, Göteborg.
authors.forename: Anna
authors.initials: A
authors.lastname: Grankvist
authors.affiliation: Department of Hematology and Coagulation, Sahlgrenska University Hospital, Göteborg.
authors.forename: Per-Ola
authors.initials: PO
authors.lastname: Andersson
authors.affiliation: Department of Internal Medicine, Karlstad Hospital, Karlstad.
authors.forename: Mattias
authors.initials: M
authors.lastname: Mattsson
authors.affiliation: Department of Hematology and Coagulation, Sahlgrenska University Hospital, Göteborg.
authors.forename: Monica
authors.initials: M
authors.lastname: Sender
authors.affiliation: Department of Hematology and Coagulation, Sahlgrenska University Hospital, Göteborg.
authors.forename: Krista
authors.initials: K
authors.lastname: Vaht
authors.affiliation: Department of Rheumatology, Sahlgrenska University Hospital, Göteborg.
authors.forename: Linnea
authors.initials: L
authors.lastname: Höper
authors.affiliation: Department of Rheumatology, Sahlgrenska University Hospital, Göteborg.
authors.forename: Egidija
authors.initials: E
authors.lastname: Sakiniene
authors.affiliation: Department of Rheumatology, Sahlgrenska University Hospital, Göteborg.
authors.forename: Estelle
authors.initials: E
authors.lastname: Trysberg
authors.affiliation: Department of Medicine, Kungälv Hospital, Kungälv, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Stenson
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Jan
authors.initials: J
authors.lastname: Fehr
authors.affiliation: Laboratory for Molecular Diagnostics, CHAMBON Laboratories, Prague, Czech Republic.
authors.forename: Sona
authors.initials: S
authors.lastname: Pekova
authors.affiliation: Mikrobiologische Institut-Klinische Mikrobiologie, Immunologie und Hygiene, Friedrich Alexander Universität Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Bogdan
authors.affiliation: Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.
authors.forename: Guido
authors.initials: G
authors.lastname: Bloemberg
authors.affiliation: Department of Clinical Microbiology/Infectious Diseases, Sahlgrenska Academy, Sahlgrenska University Hospital, Göteborg Department of Hematology and Coagulation, Sahlgrenska University Hospital, Göteborg.
authors.forename: Christine
authors.initials: C
authors.lastname: Wennerås
mesh_terms: D000368:Aged; D000711:Anaplasmataceae Infections / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy; D000783:Aneurysm / Q000382:microbiology; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001327:Autoimmune Diseases / Q000382:microbiology*; D002097:C-Reactive Protein / Q000378:metabolism; D021821:Communicable Diseases, Emerging / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology; D004269:DNA, Bacterial / Q000097:blood; D057210:Delayed Diagnosis; D005260:Female; D005334:Fever / Q000382:microbiology; D019337:Hematologic Neoplasms / Q000382:microbiology*; D006801:Humans; D002546:Ischemic Attack, Transient / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D059352:Musculoskeletal Pain / Q000382:microbiology; D011655:Pulmonary Embolism / Q000382:microbiology; D013156:Splenectomy; D017282:Tick-Borne Diseases / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D020246:Venous Thrombosis / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D002097:C-Reactive Protein
keywords: B-cell malignancies; human; infection, Neoehrlichia; tick-borne