title: Estimation of acute and chronic Q fever incidence in children during a three-year outbreak in the Netherlands and a comparison with international literature.
abstract: BACKGROUND
  In the Dutch 2007-2009 Q fever outbreak Coxiella burnetii was transmitted aerogenically from dairy goat farms to those living in the surrounding areas. Relatively few children were reported. The true number of pediatric infections is unknown. In this study, we estimate the expected number of acute and chronic childhood infections.
  
  
  METHODS
  As Coxiella was transmitted aerogenic to those living near infected dairy goat farms, we could use adult seroprevalence data to estimate infection risk for inhabitants, children and adults alike. Using Statistics Netherlands data we estimated the number of children at (high) risk for developing chronic Q fever. Literature was reviewed for childhood (0-15 years) Q fever reports and disease rates. We compared this with Dutch reported and our estimated data for 2007-2009.
  
  
  RESULTS
  In The Netherlands epidemic, 44 children were reported (1.2 % of total notifications). The childhood incidence was 0.15 compared to 2.6 per 10,000 inhabitants for adults. No complications were reported. Based on the expected similarity in childhood and adult exposure we assume that 9.8 % of children in the high-risk area had Q fever infection, resulting in 1562 acute infections during the Q fever epidemic interval. Based on the prevalence of congenital heart disease, at least 13 children are at high risk for developing chronic Q fever. In medical literature, 42 case reports described 140 childhood Q fever cases with a serious outcome (four deaths). In chronic Q fever, cardiac infections were predominant. Four outbreaks were reported involving children, describing 11 childhood cases. 36 National and/or regional studies reported seroprevalences varying between 0 and 70 %.
  
  
  CONCLUSIONS
  In the 3-year Dutch epidemic, few childhood cases were reported, with pulmonary symptoms leading, and none with a serious presentation. With an estimated 13 high-risk children for chronic infection in the high exposure area, and probably forty in the whole country, we may expect several chronic Q fever complications in the coming years in paediatric practice.
authors.affiliation: National Institute for Public Health and the Environment, Centre for Infectious Disease Control, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands. edwin.slok@rivm.nl.
authors.forename: Edwin N E
authors.initials: EN
authors.lastname: Slok
authors.affiliation: National Institute for Public Health and the Environment, Centre for Infectious Disease Control, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands. Frederika.Dijkstra@rivm.nl.
authors.forename: Frederika
authors.initials: F
authors.lastname: Dijkstra
authors.affiliation: Department of Paediatrics, Jeroen Bosch Hospital, 's-Hertogenbosch, The Netherlands. e.d.vries@jbz.nl.
authors.forename: Esther
authors.initials: E
authors.lastname: de Vries
authors.affiliation: Department of Infectious Disease Control, Municipal Health Service 'Hart voor Brabant', 's-Hertogenbosch, The Netherlands. a.rietveld@ggdhvb.nl.
authors.forename: Ariene
authors.initials: A
authors.lastname: Rietveld
authors.affiliation: National Institute for Public Health and the Environment, Centre for Infectious Disease Control, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands. Albert.Wong@rivm.nl.|Department of Statistics, Mathematical Modelling and Data Logistics, National Institute for Public Health and the Environment, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands. Albert.Wong@rivm.nl.
authors.forename: Albert
authors.initials: A
authors.lastname: Wong
authors.affiliation: National Institute for Public Health and the Environment, Centre for Infectious Disease Control, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands. Daan.Notermans@rivm.nl.
authors.forename: Daan W
authors.initials: DW
authors.lastname: Notermans
authors.affiliation: National Institute for Public Health and the Environment, Centre for Infectious Disease Control, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands. J.E.van_Steenbergen@lumc.nl.|Centre for Infectious Diseases, Leiden University Medical Centre, P.O. Box 9600, 2300 RC, Leiden, The Netherlands. J.E.van_Steenbergen@lumc.nl.
authors.forename: Jim E
authors.initials: JE
authors.lastname: van Steenbergen
mesh_terms: D000208:Acute Disease; D002648:Child; D002908:Chronic Disease; D004196:Disease Outbreaks; D006801:Humans; D015994:Incidence; D009426:Netherlands / Q000453:epidemiology; D011778:Q Fever / Q000453:epidemiology*