title: Kinetics of antibody response to Coxiella burnetii infection (Q fever): Estimation of the seroresponse onset from antibody levels.
abstract: BACKGROUND
  From 2007 to 2009, the Netherlands experienced a major Q fever epidemic. Long-term serological follow-up of acute Q fever patients enabled the investigation of longitudinal antibody responses and estimating the onset of the seroresponse in individual patients.
  
  
  METHODS
  All available IgG and IgM phase I and II antibody measurements determined by immunofluorescence assay at month 3, 6, 12, and 48 from 2321 acute Q fever patients were retrospectively analyzed. Characteristic features of the antibody response were calculated. To model the seroresponse onset, serological data from patients diagnosed with a positive C. burnetii PCR test (n=364), and therefore with a known time of infection, were used as reference.
  
  
  RESULTS
  In 9083 IgG samples and 3260 IgM samples large heterogeneity in shape and magnitude of antibody responses was observed. Phase II reached higher levels than phase I, and IgG antibodies were more persistent than IgM. The estimated seroresponse latency allowed for determining the time since start of the seroresponse from the concentrations of the different antibodies against C. burnetii.
  
  
  CONCLUSIONS
  The extraordinary large serological dataset provides new insight into the kinetics of the immunoglobulins against C. burnetii antigens. This knowledge is useful for seroprevalence studies and helps to better understand infection dynamics.
authors.affiliation: Department of Medical Microbiology and Infection Control, Jeroen Bosch Hospital, P.O. Box 90153, 5200 ME 's-Hertogenbosch, The Netherlands; Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: C C H
authors.initials: CC
authors.lastname: Wielders
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands; Hubert Department of Global Health, Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, GA 30322, USA.
authors.forename: P F M
authors.initials: PF
authors.lastname: Teunis
authors.affiliation: Laboratory for Molecular Diagnostics, Jeroen Bosch Hospital, P.O. Box 90153, 5200 ME 's-Hertogenbosch, The Netherlands.
authors.forename: M H A
authors.initials: MH
authors.lastname: Hermans
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: W
authors.initials: W
authors.lastname: van der Hoek
authors.affiliation: Department of Medical Microbiology and Infection Control, Jeroen Bosch Hospital, P.O. Box 90153, 5200 ME 's-Hertogenbosch, The Netherlands; Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands. Electronic address: p.schneeberger@jbz.nl.
authors.forename: P M
authors.initials: PM
authors.lastname: Schneeberger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000917:Antibody Formation / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011778:Q Fever / Q000453:epidemiology* / Q000276:immunology*; D016036:Seroepidemiologic Studies; D055815:Young Adult
keywords: Coxiella burnetii; Kinetics; Mathematical model; Q fever; Serology