title: Persistent high IgG phase I antibody levels against Coxiella burnetii among veterinarians compared to patients previously diagnosed with acute Q fever after three years of follow-up.
abstract: BACKGROUND
  Little is known about the development of chronic Q fever in occupational risk groups. The aim of this study was to perform long-term follow-up of Coxiella burnetii seropositive veterinarians and investigate the course of IgG phase I and phase II antibodies against C. burnetii antigens and to compare this course with that in patients previously diagnosed with acute Q fever.
  
  
  METHODS
  Veterinarians with IgG phase I ≥ 1:256 (immunofluorescence assay) that participated in a previous seroprevalence study were asked to provide a second blood sample three years later. IgG antibody profiles were compared to a group of acute Q fever patients who had IgG phase I ≥ 1:256 twelve months after diagnosis.
  
  
  RESULTS
  IgG phase I was detected in all veterinarians (n = 76) and in 85% of Q fever patients (n = 98) after three years (p<0.001). IgG phase I ≥ 1:1,024, indicating possible chronic Q fever, was found in 36% of veterinarians and 12% of patients (OR 3.95, 95% CI: 1.84-8.49).
  
  
  CONCLUSIONS
  IgG phase I persists among veterinarians presumably because of continuous exposure to C. burnetii during their work. Serological and clinical follow-up of occupationally exposed risk groups should be considered.
authors.affiliation: Department of Medical Microbiology and Infection Control, Jeroen Bosch Hospital, 's-Hertogenbosch, The Netherlands; Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Cornelia C H
authors.initials: CC
authors.lastname: Wielders
authors.affiliation: Department of Medical Microbiology and Infection Control, Jeroen Bosch Hospital, 's-Hertogenbosch, The Netherlands; Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Anneroos W
authors.initials: AW
authors.lastname: Boerman
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Barbara
authors.initials: B
authors.lastname: Schimmer
authors.affiliation: Department of Small Ruminant Health, GD Animal Health, Deventer, The Netherlands.
authors.forename: René
authors.initials: R
authors.lastname: van den Brom
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Daan W
authors.initials: DW
authors.lastname: Notermans
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Wim
authors.initials: W
authors.lastname: van der Hoek
authors.affiliation: Department of Medical Microbiology and Infection Control, Jeroen Bosch Hospital, 's-Hertogenbosch, The Netherlands; Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Schneeberger
mesh_terms: D001323:Autoantibodies / Q000276:immunology*; D016997:Coxiella burnetii / Q000276:immunology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D008297:Male; D011778:Q Fever / Q000276:immunology*; D018634:Veterinarians
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G